NIST Special Publication 800-30
Revision 1

Guide for Conducting
Risk Assessments

JOINT TASK FORCE
TRANSFORMATION INITIATIVEINFORMATIONSECURITY

Computer Security Division
Information Technology Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899-8930

September 2012

U.S. Department of Commerce
Rebecca M. Blank, Acting Secretary

National Institute of Standards and Technology
Patrick D. Gallagher, Under Secretary for Standards and Technology
and Director

Special Publication 800-30

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Reports on Computer Systems Technology
The Information Technology Laboratory (ITL) at the National Institute of Standards andTechnology (NIST) promotes the U.S. economy and public welfare by providing technicalleadership for the nation’s measurement and standards infrastructure. ITL develops tests, test
methods, reference data, proof of concept implementations, and technical analyses to advance thedevelopment and productive use of information technology. ITL’s responsibilities include thedevelopment of management, administrative, technical, and physical standards and guidelines forthe cost-effective security and privacy of other than national security-related information infederal information systems. The Special Publication 800-series reports on ITL’s research,guidelines, and outreach efforts in information system security, and its collaborative activities
with industry, government, and academic organizations.

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Authority
This publication has been developed by NIST to further its statutory responsibilities under theFederal Information Security Management Act (FISMA), Public Law (P.L.) 107-347. NIST is
responsible for developing information security standards and guidelines, including minimum
requirements for federal information systems, but such standards and guidelines shall not apply tonational security systems without the express approval of appropriate federal officials exercising
policy authority over such systems. This guideline is consistent with the requirements of the
Office of Management and Budget (OMB) Circular A-130, Section 8b(3), Securing Agency
Information Systems, as analyzed in Circular A-130, Appendix IV: Analysis of Key Sections.
Supplemental information is provided in Circular A-130, Appendix III, Security of Federal
Automated Information Resources.
Nothing in this publication should be taken to contradict the standards and guidelines mademandatory and binding on federal agencies by the Secretary of Commerce under statutory
authority. Nor should these guidelines be interpreted as altering or superseding the existing
authorities of the Secretary of Commerce, Director of the OMB, or any other federal official.
This publication may be used by nongovernmental organizations on a voluntary basis and is not
subject to copyright in the United States. Attribution would, however, be appreciated by NIST.
NIST Special Publication 800-30, 95 pages(September 2012)
CODEN: NSPUE2

Certain commercial entities, equipment, or materials may be identified in this document in order todescribe an experimental procedure or concept adequately. Such identification is not intended to imply
recommendation or endorsement by NIST, nor is it intended to imply that the entities, materials, or
equipment are necessarily the best available for the purpose.
There may be references in this publication to other publications currently under development by NIST
in accordance with its assigned statutory responsibilities. The information in this publication, including
concepts and methodologies, may be used by federal agencies even before the completion of suchcompanion publications. Thus, until each publication is completed, current requirements, guidelines,
and procedures, where they exist, remain operative. For planning and transition purposes, federal
agencies may wish to closely follow the development of these new publications by NIST.
Organizations are encouraged to review all draft publications during public comment periods andprovide feedback to NIST. All NIST publications are available at http://csrc.nist.gov/publications.

Comments on this publication may be submitted to:
National Institute of Standards and Technology
Attn: Computer Security Division, Information Technology Laboratory
100 Bureau Drive (Mail Stop 8930) Gaithersburg, MD 20899-8930
Electronic mail: sec-cert@nist.gov

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Compliance with NIST Standards and Guidelines
In accordance with the provisions of FISMA, 1 the Secretary of Commerce shall, on the basis ofstandards and guidelines developed by NIST, prescribe standards and guidelines pertaining tofederal information systems. The Secretary shall make standards compulsory and binding to theextent determined necessary by the Secretary to improve the efficiency of operation or security offederal information systems. Standards prescribed shall include information security standards
that provide minimum information security requirements and are otherwise necessary to improve
the security of federal information and information systems.
•

Federal Information Processing Standards (FIPS) are approved by the Secretary ofCommerce and issued by NIST in accordance with FISMA. FIPS are compulsory andbinding for federal agencies. 2 FISMA requires that federal agencies comply with thesestandards, and therefore, agencies may not waive their use.

•

Special Publications (SPs) are developed and issued by NIST as recommendations andguidance documents. For other than national security programs and systems, federal
agencies must follow those NIST Special Publications mandated in a Federal Information
Processing Standard. FIPS 200 mandates the use of Special Publication 800-53, as
amended. In addition, OMB policies (including OMB Reporting Instructions for FISMA
and Agency Privacy Management) state that for other than national security programs
and systems, federal agencies must follow certain specific NIST Special Publications. 3•

Other security-related publications, including interagency reports (NISTIRs) and ITL
Bulletins, provide technical and other information about NIST's activities. Thesepublications are mandatory only when specified by OMB.

•

Compliance schedules for NIST security standards and guidelines are established by
OMB in policies, directives, or memoranda (e.g., annual FISMA Reporting Guidance).4

1

The E-Government Act (P.L. 107-347) recognizes the importance of information security to the economic andnational security interests of the United States. Title III of the E-Government Act, entitled the Federal Information
Security Management Act (FISMA), emphasizes the need for organizations to develop, document, and implement anorganization-wide program to provide security for the information systems that support its operations and assets.
2

The term agency is used in this publication in lieu of the more general term organization only in those circumstanceswhere its usage is directly related to other source documents such as federal legislation or policy.
3
While federal agencies are required to follow certain specific NIST Special Publications in accordance with OMB
policy, there is flexibility in how agencies apply the guidance. Federal agencies apply the security concepts andprinciples articulated in the NIST Special Publications in accordance with and in the context of the agency’s missions,business functions, and environment of operation. Consequently, the application of NIST guidance by federal agencies
can result in different security solutions that are equally acceptable, compliant with the guidance, and meet the OMB
definition of adequate security for federal information systems. Given the high priority of information sharing andtransparency within the federal government, agencies also consider reciprocity in developing their information security
solutions. When assessing federal agency compliance with NIST Special Publications, Inspectors General, evaluators,
auditors, and assessors consider the intent of the security concepts and principles articulated within the specificguidance document and how the agency applied the guidance in the context of its mission/business responsibilities,
operational environment, and unique organizational conditions.
4
Unless otherwise stated, all references to NIST publications in this document (i.e., Federal Information Processing
Standards and Special Publications) are to the most recent version of the publication.

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Acknowledgements
This publication was developed by the Joint Task Force Transformation Initiative Interagency
Working Group with representatives from the Civil, Defense, and Intelligence Communities in an
ongoing effort to produce a unified information security framework for the federal government.
The National Institute of Standards and Technology wishes to acknowledge and thank the seniorleaders from the Departments of Commerce and Defense, the Office of the Director of National
Intelligence, the Committee on National Security Systems, and the members of the interagency
technical working group whose dedicated efforts contributed significantly to the publication. The
senior leaders, interagency working group members, and their organizational affiliations include:
Department of Defense

Office of the Director of National Intelligence

Teresa M. Takai
DoD Chief Information Officer

Adolpho Tarasiuk Jr.
Assistant DNI and Intelligence Community
Chief Information Officer

Richard Hale
Deputy Chief Information Officer for Cybersecurity

Charlene Leubecker
Deputy Intelligence Community Chief
Information Officer

Paul Grant
Director, Cybersecurity Policy

Catherine A. Henson
Director, Data Management

Dominic Cussatt
Deputy Director, Cybersecurity Policy

Greg Hall
Chief, Risk Management and Information
Security Programs Division

Kurt Eleam
Policy Advisor

National Institute of Standards and Technology

Committee on National Security Systems

Charles H. Romine
Director, Information Technology Laboratory

Teresa M. Takai
Chair, CNSS

Donna Dodson
Cybersecurity Advisor, Information Technology Laboratory

Richard Spires
Co-Chair, CNSS

Donna Dodson
Chief, Computer Security Division

Dominic Cussatt
CNSS Subcommittee Co-Chair

Ron Ross
FISMA Implementation Project Leader

Jeffrey Wilk
CNSS Subcommittee Co-Chair

Joint Task Force Transformation Initiative Interagency Working Group
Ron Ross
NIST, JTF Leader

Gary StoneburnerJohns Hopkins APL

Jennifer Fabius
The MITRE Corporation

Kelley Dempsey
NIST

Deborah Bodeau
The MITRE Corporation

Steve Rodrigo
Tenacity Solutions, Inc.

Peter Gouldmann
Department of State

Arnold Johnson
NIST

Peter Williams
Booz Allen Hamilton

Karen Quigg
The MITRE Corporation

Christina Sames
TASC

Christian Enloe
NIST

In addition to the above acknowledgments, a special note of thanks goes to Peggy Himes andElizabeth Lennon of NIST for their superb technical editing and administrative support. The
authors also gratefully acknowledge and appreciate the significant contributions from individuals
and organizations in the public and private sectors, both nationally and internationally, whosethoughtful and constructive comments improved the overall quality, thoroughness, and usefulnessof this publication.

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Special Publication 800-30

Guide for Conducting Risk Assessments________________________________________________________________________________________________DEVELOPING COMMON INFORMATION SECURITY FOUNDATIONSCOLLABORATION AMONG PUBLIC AND PRIVATE SECTOR ENTITIESIn developing standards and guidelines required by FISMA, NIST consults with other federal agencies
and offices as well as the private sector to improve information security, avoid unnecessary and costly
duplication of effort, and ensure that NIST publications are complementary with the standards andguidelines employed for the protection of national security systems. In addition to its comprehensive
public review and vetting process, NIST is collaborating with the Office of the Director of National
Intelligence (ODNI), the Department of Defense (DoD), and the Committee on National Security
Systems (CNSS) to establish a common foundation for information security across the federal
government. A common foundation for information security will provide the Intelligence, Defense, andCivil sectors of the federal government and their contractors, more uniform and consistent ways tomanage the risk to organizational operations and assets, individuals, other organizations, and the
Nation that results from the operation and use of information systems. A common foundation for
information security will also provide a strong basis for reciprocal acceptance of security authorization
decisions and facilitate information sharing. NIST is also working with public and private sector
entities to establish specific mappings and relationships between the security standards and guidelines
developed by NIST and the International Organization for Standardization and International
Electrotechnical Commission (ISO/IEC).

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Table of Contents
CHAPTER ONE INTRODUCTION .......................................................................................... 1

1.1 PURPOSE AND APPLICABILITY .................................................................................................. 2
1.2 TARGET AUDIENCE.................................................................................................................. 2
1.3 RELATED PUBLICATIONS .......................................................................................................... 3
1.4 ORGANIZATION OF THIS SPECIAL PUBLICATION.......................................................................... 3
CHAPTER TWO THE FUNDAMENTALS .................................................................................. 4

2.1 RISK MANAGEMENT PROCESS .................................................................................................. 4
2.2 RISK ASSESSMENT .................................................................................................................. 5
2.3 KEY RISK CONCEPTS ............................................................................................................... 6
2.4 APPLICATION OF RISK ASSESSMENTS ..................................................................................... 17
CHAPTER THREE THE PROCESS ...................................................................................... 23

3.1 PREPARING FOR THE RISK ASSESSMENT ................................................................................ 24
3.2 CONDUCTING THE RISK ASSESSMENT ..................................................................................... 29
3.3 COMMUNICATING AND SHARING RISK ASSESSMENT INFORMATION ............................................ 37
3.4 MAINTAINING THE RISK ASSESSMENT ..................................................................................... 38
APPENDIX A REFERENCES ............................................................................................ A-1
APPENDIX B GLOSSARY ................................................................................................ B-1
APPENDIX C ACRONYMS ............................................................................................... C-1
APPENDIX D THREAT SOURCES ..................................................................................... D-1
APPENDIX E THREAT EVENTS ........................................................................................ E-1
APPENDIX F VULNERABILITIES AND PREDISPOSING CONDITIONS ...................................... F-1
APPENDIX G LIKELIHOOD OF OCCURRENCE .................................................................... G-1
APPENDIX H IMPACT ..................................................................................................... H-1
APPENDIX IRISK DETERMINATION...................................................................................I-1

APPENDIX J INFORMING RISK RESPONSE ........................................................................ J-1
APPENDIX K RISK ASSESSMENT REPORTS ...................................................................... K-1
APPENDIX L SUMMARY OF TASKS ...................................................................................L-1

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Prologue“... Through the process of risk management, leaders must consider risk to U.S. interests fromadversaries using cyberspace to their advantage and from our own efforts to employ the global
nature of cyberspace to achieve objectives in military, intelligence, and business operations...”“... For operational plans development, the combination of threats, vulnerabilities, and impacts
must be evaluated in order to identify important trends and decide where effort should be applied
to eliminate or reduce threat capabilities; eliminate or reduce vulnerabilities; and assess,coordinate, and deconflict all cyberspace operations...”“... Leaders at all levels are accountable for ensuring readiness and security to the same degree
as in any other domain...”-- THE NATIONAL STRATEGY FOR CYBERSPACE OPERATIONSOFFICE OF THE CHAIRMAN, JOINT CHIEFS OF STAFF, U.S. DEPARTMENT OF DEFENSE

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Special Publication 800-30

Guide for Conducting Risk Assessments________________________________________________________________________________________________CAUTIONARY NOTESSCOPE AND APPLICABILITY OF RISK ASSESSMENTS•

Risk assessments are a key part of effective risk management and facilitate decision making at all
three tiers in the risk management hierarchy including the organization level, mission/businessprocess level, and information system level.

•

Because risk management is ongoing, risk assessments are conducted throughout the systemdevelopment life cycle, from pre-system acquisition (i.e., material solution analysis and technology
development), through system acquisition (i.e., engineering/manufacturing development andproduction/deployment), and on into sustainment (i.e., operations/support).

•

There are no specific requirements with regard to: (i) the formality, rigor, or level of detail thatcharacterizes any particular risk assessment; (ii) the methodologies, tools, and techniques used to
conduct such risk assessments; or (iii) the format and content of assessment results and any
associated reporting mechanisms. Organizations have maximum flexibility on how risk assessments
are conducted and are encouraged to apply the guidance in this document so that the various needsof organizations can be addressed and the risk assessment activities can be integrated into broader
organizational risk management processes.

•

Organizations are also cautioned that risk assessments are often not precise instruments ofmeasurement and reflect: (i) the limitations of the specific assessment methodologies, tools, andtechniques employed; (ii) the subjectivity, quality, and trustworthiness of the data used; (iii) theinterpretation of assessment results; and (iv) the skills and expertise of those individuals or groups
conducting the assessments.

•

Since cost, timeliness, and ease of use are a few of the many important factors in the application ofrisk assessments, organizations should attempt to reduce the level of effort for risk assessments by
sharing risk-related information, whenever possible.

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CHAPTER ONE

INTRODUCTION
THE NEED FOR RISK ASSESSMENTS TO SUPPORT ENTERPRISE-WIDE RISK MANAGEMENT

O

rganizations 5 in the public and private sectors depend on information technology 6 andinformation systems 7 to successfully carry out their missions and business functions.
Information systems can include very diverse entities ranging from office networks,
financial and personnel systems to very specialized systems (e.g., industrial/process control
systems, weapons systems, telecommunications systems, and environmental control systems).
Information systems are subject to serious threats that can have adverse effects on organizational
operations and assets, individuals, other organizations, and the Nation by exploiting both known
and unknown vulnerabilities to compromise the confidentiality, integrity, or availability of theinformation being processed, stored, or transmitted by those systems. Threats to information
systems can include purposeful attacks, environmental disruptions, human/machine errors, andstructural failures, and can result in harm to the national and economic security interests of theUnited States. Therefore, it is imperative that leaders and managers at all levels understand their
responsibilities and are held accountable for managing information security risk—that is, the risk
associated with the operation and use of information systems that support the missions andbusiness functions of their organizations.

Risk assessment is one of the fundamental components of an organizational risk management
process as described in NIST Special Publication 800-39. Risk assessments are used to identify,
estimate, and prioritize risk to organizational operations (i.e., mission, functions, image, andreputation), organizational assets, individuals, other organizations, and the Nation, resulting fromthe operation and use of information systems. The purpose of risk assessments is to inform
decision makers and support risk responses by identifying: (i) relevant threats to organizations or
threats directed through organizations against other organizations; (ii) vulnerabilities both internaland external to organizations; (iii) impact (i.e., harm) to organizations that may occur given thepotential for threats exploiting vulnerabilities; and (iv) likelihood that harm will occur. The end
result is a determination of risk (i.e., typically a function of the degree of harm and likelihood ofharm occurring). Risk assessments can be conducted at all three tiers in the risk management
hierarchy—including Tier 1 (organization level), Tier 2 (mission/business process level), and Tier
3 (information system level). At Tiers 1 and 2, organizations use risk assessments to evaluate, forexample, systemic information security-related risks associated with organizational governanceand management activities, mission/business processes, enterprise architecture, or the funding of
information security programs. At Tier 3, organizations use risk assessments to more effectively
support the implementation of the Risk Management Framework (i.e., security categorization;
security control selection, implementation, and assessment; information system and common
control authorization; and security control monitoring). 8
5
The term organization describes an entity of any size, complexity, or positioning within an organizational structure(e.g., a federal agency or, as appropriate, any of its operational elements) that is charged with carrying out assigned
mission/business processes and that uses information systems in support of those processes.
6

Organizations also manage information technology in the form of common infrastructures, sets of shared services, andsets of common controls.
7
An information system is a discrete set of information resources organized for the collection, processing, maintenance,
use, sharing, dissemination, or disposition of information.
8

The Risk Management Framework is described in NIST Special Publication 800-37.

CHAPTER 1

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1.1 PURPOSE AND APPLICABILITY
The purpose of Special Publication 800-30 is to provide guidance for conducting risk assessmentsof federal information systems and organizations, amplifying the guidance in Special Publication
800-39. Risk assessments, carried out at all three tiers in the risk management hierarchy, are partof an overall risk management process—providing senior leaders/executives with the informationneeded to determine appropriate courses of action in response to identified risks. In particular,
this document provides guidance for carrying out each of the steps in the risk assessment process(i.e., preparing for the assessment, conducting the assessment, communicating the results of theassessment, and maintaining the assessment) and how risk assessments and other organizationalrisk management processes complement and inform each other. Special Publication 800-30 also
provides guidance to organizations on identifying specific risk factors to monitor on an ongoingbasis, so that organizations can determine whether risks have increased to unacceptable levels(i.e., exceeding organizational risk tolerance) and different courses of action should be taken.
This publication satisfies the requirements of FISMA and meets or exceeds the information
security requirements established for executive agencies 9 by the Office of Management andBudget (OMB) in Circular A-130, Appendix III, Security of Federal Automated Information
Resources. The guidelines in this publication are applicable to all federal information systems
other than those systems designated as national security systems as defined in 44 U.S.C., Section
3542. The guidelines have been broadly developed from a technical perspective to complement
similar guidelines for national security systems and may be used for such systems with theapproval of appropriate federal officials exercising policy authority over such systems. State,
local, and tribal governments, as well as private sector organizations are encouraged to consider
using these guidelines, as appropriate.

1.2 TARGET AUDIENCEThis publication is intended to serve a diverse group of risk management professionals including:•Individuals with oversight responsibilities for risk management (e.g., heads of agencies, chief
executive officers, chief operating officers, risk executive [function]);•Individuals with responsibilities for conducting organizational missions/business functions(e.g., mission/business owners, information owners/stewards, authorizing officials);•

Individuals with responsibilities for acquiring information technology products, services, orinformation systems (e.g., acquisition officials, procurement officers, contracting officers);•

Individuals with information system/security design, development, and implementation
responsibilities (e.g., program managers, enterprise architects, information security architects,
information system/security engineers, information systems integrators);•

Individuals with information security oversight, management, and operational responsibilities(e.g., chief information officers, senior information security officers,10 information security
managers, information system owners, common control providers); and9An executive agency is: (i) an executive department specified in 5 U.S.C., Section 101; (ii) a military department
specified in 5 U.S.C., Section 102; (iii) an independent establishment as defined in 5 U.S.C., Section 104(1); and (iv) awholly owned government corporation fully subject to the provisions of 31 U.S.C., Chapter 91. In this publication, theterm executive agency is synonymous with the term federal agency.

10

At the agency level, this position is known as the Senior Agency Information Security Officer. Organizations may
also refer to this position as the Chief Information Security Officer.

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Individuals with information security/risk assessment and monitoring responsibilities (e.g.,system evaluators, penetration testers, security control assessors, risk assessors, independent
verifiers/validators, inspectors general, auditors).

1.3 RELATED PUBLICATIONS
The risk assessment approach described in this publication is supported by a series of security
standards and guidelines necessary for managing information security risk. In addition to thispublication, the Special Publications developed by the Joint Task Force Transformation Initiative
supporting the unified information security framework for the federal government include:•

Special Publication 800-39, Managing Information Security Risk: Organization, Mission, andInformation System View; 11•

Special Publication 800-37, Guide for Applying the Risk Management Framework to Federal
Information Systems: A Security Life Cycle Approach;•Special Publication 800-53, Recommended Security Controls for Federal Information
Systems and Organizations; and•Special Publication 800-53A, Guide for Assessing the Security Controls in Federal
Information Systems and Organizations: Building Effective Security Assessment Plans.

The concepts and principles associated with the risk assessment processes and approaches
contained in this publication are intended to be similar to and consistent with the processes andapproaches described in International Organization for Standardization (ISO) and International
Electrotechnical Commission (IEC) standards. Extending the concepts and principles of theseinternational standards for the federal government and its contractors and promoting the reuse ofrisk assessment results, reduces the burden on organizations that must conform to ISO/IEC andNIST standards.

1.4 ORGANIZATION OF THIS SPECIAL PUBLICATIONThe remainder of this special publication is organized as follows:•

Chapter Two describes: (i) the risk management process and how risk assessments are an
integral part of that process; (ii) the basic terminology used in conducting risk assessments;and (iii) how risk assessments can be applied across the organization’s risk management tiers(i.e., organization level, mission/business process level, and information system level).

•

Chapter Three describes the process of assessing information security risk including: (i) ahigh-level overview of the risk assessment process; (ii) the activities necessary to prepare fora risk assessment; (iii) the activities necessary to conduct a risk assessment; (iv) the activities
necessary to communicate risk assessment results and share risk-related information acrossthe organization; and (v) the activities necessary to maintain the results of a risk assessment.

•

Supporting appendices provide additional risk assessment information including: (i) generalreferences; (ii) a glossary of terms; (iii) acronyms; (iv) threat sources; (v) threat events; (vi)vulnerabilities and predisposing conditions; (vii) likelihood of threat event occurrence; (viii)
organizational impact; (ix) risk determination; (x) informing risk response; (xi) essential
information for risk assessment reports; and (xii) a summary of risk assessment tasks.

11

Special Publication 800-39 supersedes Special Publication 800-30 as the primary source for guidance on information
security risk management.

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CHAPTER TWO

THE FUNDAMENTALSBASIC CONCEPTS ASSOCIATED WITH RISK ASSESSMENTS

T

his chapter describes the fundamental concepts associated with assessing information
security risk within an organization including: (i) a high-level overview of the risk
management process and the role risk assessments play in that process; (ii) the basic
concepts used in conducting risk assessments; and (iii) how risk assessments can be applied
across the organization’s risk management tiers. 12

2.1 RISK MANAGEMENT PROCESS
Risk assessment is a key component of a holistic, organization-wide risk management process as
defined in NIST Special Publication 800-39, Managing Information Security Risk: Organization,
Mission, and Information System View. Risk management processes include: (i) framing risk; (ii)assessing risk; (iii) responding to risk; and (iv) monitoring risk. Figure 1 illustrates the four steps
in the risk management process—including the risk assessment step and the information andcommunications flows necessary to make the process work effectively. 13

ASSESS

Information andCommunications Flows

Information andCommunications FlowsFRAME

MONITORRESPOND

FIGURE 1: RISK ASSESSMENT WITHIN THE RISK MANAGEMENT PROCESSThe first component of risk management addresses how organizations frame risk or establish arisk context—that is, describing the environment in which risk-based decisions are made. The
purpose of the risk framing component is to produce a risk management strategy that addresses
how organizations intend to assess risk, respond to risk, and monitor risk—making explicit and
12
NIST Special Publication 800-39 provides guidance on the three tiers in the risk management hierarchy including
Tier 1 (organization), Tier 2 (mission/business process), and Tier 3 (information system).
13

Many of the outputs from the risk framing step provide essential inputs to the risk assessment step and the associatedrisk assessment process. These include, for example, the risk management strategy, organizational risk tolerance, risk
assessment methodology, assumptions, constraints, and mission/business priorities.

CHAPTER 2

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transparent the risk perceptions that organizations routinely use in making both investment andoperational decisions. The risk management strategy establishes a foundation for managing risk
and delineates the boundaries for risk-based decisions within organizations. 14
The second component of risk management addresses how organizations assess risk within thecontext of the organizational risk frame. The purpose of the risk assessment component is to
identify: (i) threats to organizations (i.e., operations, assets, or individuals) or threats directed
through organizations against other organizations or the Nation; (ii) vulnerabilities internal andexternal to organizations; 15 (iii) the harm (i.e., adverse impact) that may occur given the potential
for threats exploiting vulnerabilities; and (iv) the likelihood that harm will occur. The end result isa determination of risk (i.e., typically a function of the degree of harm and likelihood of harm
occurring).
The third component of risk management addresses how organizations respond to risk once thatrisk is determined based on the results of a risk assessment. The purpose of the risk responsecomponent is to provide a consistent, organization-wide response to risk in accordance with theorganizational risk frame by: (i) developing alternative courses of action for responding to risk;(ii) evaluating the alternative courses of action; (iii) determining appropriate courses of action
consistent with organizational risk tolerance; and (iv) implementing risk responses based on
selected courses of action.
The fourth component of risk management addresses how organizations monitor risk over time.
The purpose of the risk monitoring component is to: (i) determine the ongoing effectiveness ofrisk responses (consistent with the organizational risk frame); (ii) identify risk-impacting changes
to organizational information systems and the environments in which the systems operate; 16 and(iii) verify that planned risk responses are implemented and information security requirements
derived from and traceable to organizational missions/business functions, federal legislation,
directives, regulations, policies, standards, and guidelines are satisfied.

2.2 RISK ASSESSMENT
This publication focuses on the risk assessment component of risk management—providing a
step-by-step process for organizations on: (i) how to prepare for risk assessments; (ii) how to
conduct risk assessments; (iii) how to communicate risk assessment results to key organizational
personnel; and (iv) how to maintain the risk assessments over time. Risk assessments are notsimply one-time activities that provide permanent and definitive information for decision makers
to guide and inform responses to information security risks. Rather, organizations employ risk
assessments on an ongoing basis throughout the system development life cycle and across all of
the tiers in the risk management hierarchy—with the frequency of the risk assessments and theresources applied during the assessments, commensurate with the expressly defined purpose andscope of the assessments.
14

In the absence of an explicit or formal organizational risk management strategy, organizational resources (e.g., tools,
data repositories) and references (e.g., exemplary risk assessment reports) can be used to discern those aspects of theorganization’s approach to risk management that affect risk assessment.

15

Organizational vulnerabilities are not confined to information systems but can include, for example, vulnerabilities ingovernance structures, mission/business processes, enterprise architecture, information security architecture, facilities,
equipment, system development life cycle processes, supply chain activities, and external service providers.
16

Environments of operation include, but are not limited to: the threat space; vulnerabilities; missions/business
functions; mission/business processes; enterprise and information security architectures; information technologies;
personnel; facilities; supply chain relationships; organizational governance/culture; procurement/acquisition processes;organizational policies/procedures; organizational assumptions, constraints, risk tolerance, and priorities/trade-offs).

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Risk assessments address the potential adverse impacts to organizational operations and assets,
individuals, other organizations, and the economic and national security interests of the UnitedStates, arising from the operation and use of information systems and the information processed,
stored, and transmitted by those systems. Organizations conduct risk assessments to determine
risks that are common to the organization’s core missions/business functions, mission/businessprocesses, mission/business segments, common infrastructure/support services, or information
systems. Risk assessments can support a wide variety of risk-based decisions and activities byorganizational officials across all three tiers in the risk management hierarchy including, but notlimited to, the following:• Development of an information security architecture;• Definition of interconnection requirements for information systems (including systems
supporting mission/business processes and common infrastructure/support services);• Design of security solutions for information systems and environments of operation including
selection of security controls, information technology products, suppliers/supply chain, andcontractors;• Authorization (or denial of authorization) to operate information systems or to use security
controls inherited by those systems (i.e., common controls);• Modification of missions/business functions and/or mission/business processes permanently,
or for a specific time frame (e.g., until a newly discovered threat or vulnerability is addressed,
until a compensating control is replaced);• Implementation of security solutions (e.g., whether specific information technology products
or configurations for those products meet established requirements); and• Operation and maintenance of security solutions (e.g., continuous monitoring strategies andprograms, ongoing authorizations).
Because organizational missions and business functions, supporting mission/business processes,
information systems, threats, and environments of operation tend to change over time, the validity
and usefulness of any risk assessment is bounded in time.

2.3 KEY RISK CONCEPTS
Risk is a measure of the extent to which an entity is threatened by a potential circumstance or
event, and is typically a function of: (i) the adverse impacts that would arise if the circumstanceor event occurs; and (ii) the likelihood of occurrence. Information security risks are those risks
that arise from the loss of confidentiality, integrity, or availability of information or information
systems and reflect the potential adverse impacts to organizational operations (i.e., mission,functions, image, or reputation), organizational assets, individuals, other organizations, and the
Nation. Risk assessment is the process of identifying, estimating, and prioritizing information
security risks. Assessing risk requires the careful analysis of threat and vulnerability information
to determine the extent to which circumstances or events could adversely impact an organizationand the likelihood that such circumstances or events will occur.
A risk assessment methodology typically includes: (i) a risk assessment process (as described in
Chapter Three); (ii) an explicit risk model, defining key terms and assessable risk factors and therelationships among the factors; (iii) an assessment approach (e.g., quantitative, qualitative, orsemi-qualitative), specifying the range of values those risk factors can assume during the risk
assessment and how combinations of risk factors are identified/analyzed so that values of those

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factors can be functionally combined to evaluate risk; and (iv) an analysis approach (e.g., threatoriented, asset/impact-oriented, or vulnerability-oriented), describing how combinations of risk
factors are identified/analyzed to ensure adequate coverage of the problem space at a consistentlevel of detail. Risk assessment methodologies are defined by organizations and are a componentof the risk management strategy developed during the risk framing step of the risk management
process.17 Figure 2 illustrates the fundamental components in organizational risk frames and therelationships among those components.

- Risk Assumptions- Risk Constraints- Priorities and Tradeoffs- Risk Tolerance- Uncertainty

ORGANIZATIONAL RISK FRAME
RISK MANAGEMENT STRATEGY OR APPROACH- Establishes Foundation
for Risk Management- Delineates Boundaries
for Risk-Based Decisions
DETERMINESDETERMINES

Risk Assessment Methodology

Risk Assessment
Process

Risk
Model

Assessment
Approach

Analysis
Approach

FIGURE 2: RELATIONSHIP AMONG RISK FRAMING COMPONENTS

Organizations can use a single risk assessment methodology or can employ multiple assessment
methodologies, with the selection of a specific methodology depending on, for example: (i) thetime frame for investment planning or for planning policy changes; (ii) the complexity/maturityof organizational mission/business processes (by enterprise architecture segments); (iii) the phaseof the information systems in the system development life cycle; or (iv) the criticality/sensitivity 18of the information and information systems supporting the core organizational missions/business
functions. By making explicit the risk model, the assessment approach, and the analysis approach
employed, and requiring as part of the assessment process, a rationale for the assessed values ofrisk factors, organizations can increase the reproducibility and repeatability of risk assessments. 19

17

Risk assessment methodologies are influenced in large measure by the organizational risk management strategy.
However, risk assessment methodologies can be customized for each risk assessment based on the purpose and scopeof the assessment and the specific inputs organizations choose to make regarding the risk assessment process, risk
model, assessment approach, and analysis approach.
18

NIST Special Publication 800-60 discusses the concepts of criticality and sensitivity of information with respect tosecurity categorization.
19
Reproducibility refers to the ability of different experts to produce the same results from the same data. Repeatability
refers to the ability to repeat the assessment in the future, in a manner that is consistent with and hence comparable toprior assessments—enabling the organization to identify trends.

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2.3.1 Risk Models
Risk models define the risk factors to be assessed and the relationships among those factors.20
Risk factors are characteristics used in risk models as inputs to determining levels of risk in risk
assessments. Risk factors are also used extensively in risk communications to highlight whatstrongly affects the levels of risk in particular situations, circumstances, or contexts. Typical risk
factors include threat, vulnerability, impact, likelihood, and predisposing condition. Risk factors
can be decomposed into more detailed characteristics (e.g., threats decomposed into threatsources and threat events). 21 These definitions are important for organizations to document prior
to conducting risk assessments because the assessments rely upon well-defined attributes of
threats, vulnerabilities, impact, and other risk factors to effectively determine risk.
Threats
A threat is any circumstance or event with the potential to adversely impact organizational
operations and assets, individuals, other organizations, or the Nation through an information
system via unauthorized access, destruction, disclosure, or modification of information, and/or
denial of service. 22 Threat events are caused by threat sources. A threat source is characterized as:(i) the intent and method targeted at the exploitation of a vulnerability; or (ii) a situation andmethod that may accidentally exploit a vulnerability. In general, types of threat sources include:(i) hostile cyber or physical attacks; (ii) human errors of omission or commission; (iii) structural
failures of organization-controlled resources (e.g., hardware, software, environmental controls);and (iv) natural and man-made disasters, accidents, and failures beyond the control of theorganization. Various taxonomies of threat sources have been developed. 23 Some taxonomies of
threat sources use the type of adverse impacts as an organizing principle. Multiple threat sources
can initiate or cause the same threat event—for example, a provisioning server can be taken offline by a denial-of-service attack, a deliberate act by a malicious system administrator, anadministrative error, a hardware fault, or a power failure.
Risk models differ in the degree of detail and complexity with which threat events are identified.
When threat events are identified with great specificity, threat scenarios can be modeled,developed, and analyzed. 24 Threat events for cyber or physical attacks are characterized by thetactics, techniques, and procedures (TTPs) employed by adversaries. Understanding adversarybased threat events gives organizations insights into the capabilities associated with certain threatsources. In addition, having greater knowledge about who is carrying out the attacks gives
organizations a better understanding of what adversaries desire to gain by the attacks. Knowing
20

Documentation of a risk model includes: (i) identification of risk factors (definitions, descriptions, value scales); and(ii) identification of the relationships among those risk factors (both conceptual relationships, presented descriptively,
and algorithms for combining values). The risk model presented in this section (and described in Appendices D-I) does
not specify algorithms for combining values.
21

A risk factor can have a single assessable characteristic (e.g., impact severity) or multiple characteristics, some ofwhich may be assessable and some of which may not be assessable. Characteristics which are not assessable typically
help determine what lower-level characteristics are relevant. For example, a threat source has a (characteristic) threat
type (using a taxonomy of threat types, which are nominal rather than assessable). The threat type determines which of
the more detailed characteristics are relevant (e.g., a threat source of type adversary has associated characteristics ofcapabilities, intent, and targeting, which are directly assessable characteristics).
22

Organizations can choose to specify threat events as: (i) single events, actions, or circumstances; or (ii) sets and/or
sequences of related actions, activities, and/or circumstances.
23

Appendix D provides an exemplary taxonomy of threat sources and associated threat characteristics.

24

A threat scenario is a set of discrete threat events, attributed to a specific threat source or multiple threat sources,
ordered in time, that result in adverse effects.

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the intent and targeting aspects of a potential attack helps organizations narrow the set of threat
events that are most relevant to consider.
Threat shifting is the response of adversaries to perceived safeguards and/or countermeasures(i.e., security controls), in which adversaries change some characteristic of their intent/targetingin order to avoid and/or overcome those safeguards/countermeasures. Threat shifting can occur in
one or more domains including: (i) the time domain (e.g., a delay in an attack or illegal entry to
conduct additional surveillance); (ii) the target domain (e.g., selecting a different target that is not
as well protected); (iii) the resource domain (e.g., adding resources to the attack in order to reduce
uncertainty or overcome safeguards and/or countermeasures); or (iv) the attack planning/attack
method domain (e.g., changing the attack weapon or attack path). Threat shifting is a naturalconsequence of a dynamic set of interactions between threat sources and types of organizational
assets targeted. With more sophisticated threat sources, it also tends to default to the path of least
resistance to exploit particular vulnerabilities, and the responses are not always predictable. In
addition to the safeguards and/or countermeasures implemented and the impact of a successful
exploit of an organizational vulnerability, another influence on threat shifting is the benefit to theattacker. That perceived benefit on the attacker side can also influence how much and when threat
shifting occurs.
Vulnerabilities and Predisposing Conditions
A vulnerability is a weakness in an information system, system security procedures, internal
controls, or implementation that could be exploited by a threat source. 25 Most information systemvulnerabilities can be associated with security controls that either have not been applied (either
intentionally or unintentionally), or have been applied, but retain some weakness. However, it isalso important to allow for the possibility of emergent vulnerabilities that can arise naturally overtime as organizational missions/business functions evolve, environments of operation change,
new technologies proliferate, and new threats emerge. In the context of such change, existing
security controls may become inadequate and may need to be reassessed for effectiveness. The
tendency for security controls to potentially degrade in effectiveness over time reinforces theneed to maintain risk assessments during the entire system development life cycle and also theimportance of continuous monitoring programs to obtain ongoing situational awareness of theorganizational security posture.
Vulnerabilities are not identified only within information systems. Viewing information systems
in a broader context, vulnerabilities can be found in organizational governance structures (e.g.,
the lack of effective risk management strategies and adequate risk framing, poor intra-agency
communications, inconsistent decisions about relative priorities of missions/business functions, ormisalignment of enterprise architecture to support mission/business activities). Vulnerabilities canalso be found in external relationships (e.g., dependencies on particular energy sources, supply
chains, information technologies, and telecommunications providers), mission/business processes(e.g., poorly defined processes or processes that are not risk-aware), and enterprise/information
security architectures (e.g., poor architectural decisions resulting in lack of diversity or resiliency
in organizational information systems). 26

25
The severity of a vulnerability is an assessment of the relative importance of mitigating/remediating the vulnerability.
The severity can be determined by the extent of the potential adverse impact if such a vulnerability is exploited by athreat source. Thus, the severity of vulnerabilities, in general, is context-dependent.
26
NIST Special Publication 800-39 provides guidance on vulnerabilities at all three tiers in the risk management
hierarchy and the potential adverse impact that can occur if threats exploit such vulnerabilities.

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In general, risks materialize as a result of a series of threat events, each of which takes advantage
of one or more vulnerabilities. Organizations define threat scenarios to describe how the events
caused by a threat source can contribute to or cause harm. Development of threat scenarios isanalytically useful, since some vulnerabilities may not be exposed to exploitation unless and until
other vulnerabilities have been exploited. Analysis that illuminates how a set of vulnerabilities,
taken together, could be exploited by one or more threat events is therefore more useful than theanalysis of individual vulnerabilities. In addition, a threat scenario tells a story, and hence isuseful for risk communication as well as for analysis.
In addition to vulnerabilities as described above, organizations also consider predisposing
conditions. A predisposing condition is a condition that exists within an organization, a mission
or business process, enterprise architecture, information system, or environment of operation,
which affects (i.e., increases or decreases) the likelihood that threat events, once initiated, resultin adverse impacts to organizational operations and assets, individuals, other organizations, or the
Nation. 27 Predisposing conditions include, for example, the location of a facility in a hurricane- or
flood-prone region (increasing the likelihood of exposure to hurricanes or floods) or a stand-alone
information system with no external network connectivity (decreasing the likelihood of exposure
to a network-based cyber attack). Vulnerabilities resulting from predisposing conditions thatcannot be easily corrected could include, for example, gaps in contingency plans, use of outdated
technologies, or weaknesses/deficiencies in information system backup and failover mechanisms.
In all cases, these types of vulnerabilities create a predisposition toward threat events having
adverse impacts on organizations. Vulnerabilities (including those attributed to predisposing
conditions) are part of the overall security posture of organizational information systems andenvironments of operation that can affect the likelihood of occurrence of a threat event.
Likelihood
The likelihood of occurrence is a weighted risk factor based on an analysis of the probability thata given threat is capable of exploiting a given vulnerability (or set of vulnerabilities). The
likelihood risk factor combines an estimate of the likelihood that the threat event will be initiatedwith an estimate of the likelihood of impact (i.e., the likelihood that the threat event results inadverse impacts). For adversarial threats, an assessment of likelihood of occurrence is typically
based on: (i) adversary intent; (ii) adversary capability; and (iii) adversary targeting. For otherthan adversarial threat events, the likelihood of occurrence is estimated using historical evidence,empirical data, or other factors. Note that the likelihood that a threat event will be initiated or will
occur is assessed with respect to a specific time frame (e.g., the next six months, the next year, or
the period until a specified milestone is reached). If a threat event is almost certain to be initiatedor occur in the (specified or implicit) time frame, the risk assessment may take into consideration
the estimated frequency of the event. The likelihood of threat occurrence can also be based on thestate of the organization (including for example, its core mission/business processes, enterprisearchitecture, information security architecture, information systems, and environments in whichthose systems operate)—taking into consideration predisposing conditions and the presence andeffectiveness of deployed security controls to protect against unauthorized/undesirable behavior,detect and limit damage, and/or maintain or restore mission/business capabilities. The likelihoodof impact addresses the probability (or possibility) that the threat event will result in an adverse
impact, regardless of the magnitude of harm that can be expected.

27

The concept of predisposing condition is also related to the term susceptibility or exposure. Organizations are notsusceptible to risk (or exposed to risk) if a threat cannot exploit a vulnerability to cause adverse impact. For example,
organizations that do not employ database management systems are not vulnerable to the threat of SQL injections andtherefore, are not susceptible to such risk.

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Organizations typically employ a three-step process to determine the overall likelihood of threat
events. First, organizations assess the likelihood that threat events will be initiated (for adversarial
threat events) or will occur (for non-adversarial threat events). Second, organizations assess thelikelihood that the threat events once initiated or occurring, will result in adverse impacts or harm
to organizational operations and assets, individuals, other organizations, or the Nation. Finally,organizations assess the overall likelihood as a combination of likelihood of initiation/occurrence
and likelihood of resulting in adverse impact.
Threat-vulnerability pairing (i.e., establishing a one-to-one relationship between threats andvulnerabilities) may be undesirable when assessing likelihood at the mission/business functionlevel, and in many cases, can be problematic even at the information system level due to thepotentially large number of threats and vulnerabilities. This approach typically drives the level ofdetail in identifying threat events and vulnerabilities, rather than allowing organizations to makeeffective use of threat information and/or to identify threats at a level of detail that is meaningful.
Depending on the level of detail in threat specification, a given threat event could exploit multiple
vulnerabilities. In assessing likelihoods, organizations examine vulnerabilities that threat events
could exploit and also the mission/business function susceptibility to events for which no security
controls or viable implementations of security controls exist (e.g., due to functional dependencies,
particularly external dependencies). In certain situations, the most effective way to reduce
mission/business risk attributable to information security risk is to redesign the mission/businessprocesses so there are viable work-arounds when information systems are compromised. Using
the concept of threat scenarios described above, may help organizations overcome some of thelimitations of threat-vulnerability pairing.
Impact
The level of impact from a threat event is the magnitude of harm that can be expected to result
from the consequences of unauthorized disclosure of information, unauthorized modification of
information, unauthorized destruction of information, or loss of information or information
system availability. Such harm can be experienced by a variety of organizational and nonorganizational stakeholders including, for example, heads of agencies, mission and businessowners, information owners/stewards, mission/business process owners, information systemowners, or individuals/groups in the public or private sectors relying on the organization—in
essence, anyone with a vested interest in the organization’s operations, assets, or individuals,
including other organizations in partnership with the organization, or the Nation. 28 Organizations
make explicit: (i) the process used to conduct impact determinations; (ii) assumptions related to
impact determinations; (iii) sources and methods for obtaining impact information; and (iv) the
rationale for conclusions reached with regard to impact determinations.
Organizations may explicitly define how established priorities and values guide the identificationof high-value assets and the potential adverse impacts to organizational stakeholders. If suchinformation is not defined, priorities and values related to identifying targets of threat sources andassociated organizational impacts can typically be derived from strategic planning and policies.
For example, security categorization levels indicate the organizational impacts of compromisingdifferent types of information. Privacy Impact Assessments and criticality levels (when defined aspart of contingency planning or Mission/Business Impact Analysis) indicate the adverse impactsof destruction, corruption, or loss of accountability for information resources to organizations.
28

The term organizational assets can have a very wide scope of applicability to include, for example, high-impact
programs, physical plant, mission-critical information systems, personnel, equipment, or a logically related group of
systems. More broadly, organizational assets represent any resource or set of resources which the organization values,
including intangible assets such as image or reputation.

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Strategic plans and policies also assert or imply the relative priorities of immediate or near-term
mission/business function accomplishment and long-term organizational viability (which can beundermined by the loss of reputation or by sanctions resulting from the compromise of sensitive
information). Organizations can also consider the range of effects of threat events including therelative size of the set of resources affected, when making final impact determinations. Risk
tolerance assumptions may state that threat events with an impact below a specific value do not
warrant further analysis.
Risk
Figure 3 illustrates an example of a risk model including the key risk factors discussed above andthe relationship among the factors. Each of the risk factors is used in the risk assessment process
in Chapter Three.

ThreatSourceinitiates

with
with
Likelihood of
Characteristics
Initiation(e.g., Capability, Intent, andTargeting for Adversarial
Threats)

ThreatEvent

exploitswithwith
Likelihood ofSequence of
Success
actions, activities,
or scenarios

Inputs from Risk Framing Step

Vulnerability

causingwith Severity

withDegreeIn the context of

Predisposing
Conditions
with
Pervasiveness(Risk Management Strategy or Approach)
Influencing and Potentially Modifying Key
Risk Factors

Security Controls
Planned / Implemented

withEffectiveness

Adverse
Impactwith Risk
as a combination of
Impact and Likelihood
producing

ORGANIZATIONAL RISKTo organizational operations (mission,functions, image, reputation), organizational
assets, individuals, other organizations, andthe Nation.

Risk Framing

FIGURE 3: GENERIC RISK MODEL WITH KEY RISK FACTORS

As noted above, risk is a function of the likelihood of a threat event’s occurrence and potential
adverse impact should the event occur. This definition accommodates many types of adverse
impacts at all tiers in the risk management hierarchy described in Special Publication 800-39(e.g., damage to image or reputation of the organization or financial loss at Tier 1; inability tosuccessfully execute a specific mission/business process at Tier 2; or the resources expended in
responding to an information system incident at Tier 3). It also accommodates relationships
among impacts (e.g., loss of current or future mission/business effectiveness due to the loss ofdata confidentiality; loss of confidence in critical information due to loss of data or system
integrity; or unavailability or degradation of information or information systems). This broad
definition also allows risk to be represented as a single value or as a vector (i.e., multiple values),
in which different types of impacts are assessed separately. For purposes of risk communication,risk is generally grouped according to the types of adverse impacts (and possibly the time frames
in which those impacts are likely to be experienced).

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Aggregation
Organizations may use risk aggregation to roll up several discrete or lower-level risks into a moregeneral or higher-level risk. Organizations may also use risk aggregation to efficiently manage
the scope and scale of risk assessments involving multiple information systems and multiple
mission/business processes with specified relationships and dependencies among those systems
and processes. Risk aggregation, conducted primarily at Tiers 1 and 2 and occasionally at Tier 3,
assesses the overall risk to organizational operations, assets, and individuals given the set of
discrete risks. In general, for discrete risks (e.g., the risk associated with a single information
system supporting a well-defined mission/business process), the worst-case impact establishes anupper bound for the overall risk to organizational operations, assets, and individuals. 29 One issue
for risk aggregation is that this upper bound for risk may fail to apply. For example, it may be
advantageous for organizations to assess risk at the organization level when multiple risksmaterialize concurrently or when the same risk materializes repeatedly over a period of time. In
such situations, there is the possibility that the amount of overall risk incurred is beyond the risk
capacity of the organization, and therefore the overall impact to organizational operations andassets (i.e., mission/business impact) goes beyond that which was originally assessed for eachspecific risk.
When aggregating risk, organizations consider the relationship among various discrete risks. For
example, there may be a cause and effect relationship in that if one risk materializes, another risk
is more or less likely to materialize. If there is a direct or inverse relationship among discreterisks, then the risks can be coupled (in a qualitative sense) or correlated (in a quantitative sense)
either in a positive or negative manner. Risk coupling or correlation (i.e., finding relationships
among risks that increase or decrease the likelihood of any specific risk materializing) can bedone at Tiers 1, 2, or 3.
Uncertainty
Uncertainty is inherent in the evaluation of risk, due to such considerations as: (i) limitations on
the extent to which the future will resemble the past; (ii) imperfect or incomplete knowledge ofthe threat (e.g., characteristics of adversaries including tactics, techniques, and procedures); (iii)
undiscovered vulnerabilities in technologies or products; and (iv) unrecognized dependencies,
which can lead to unforeseen impacts. Uncertainty about the value of specific risk factors can also
be due to the step in the RMF or phase in the system development life cycle at which a risk
assessment is performed. For example, at early phases in the system development life cycle, thepresence and effectiveness of security controls may be unknown, while at later phases in the life
cycle, the cost of evaluating control effectiveness may outweigh the benefits in terms of more
fully informed decision making. Finally, uncertainty can be due to incomplete knowledge of therisks associated with other information systems, mission/ business processes, services, common
infrastructures, and/or organizations. The degree of uncertainty in risk assessment results, due tothese different reasons, can be communicated in the form of the results (e.g., by expressing results
qualitatively, by providing ranges of values rather than single values for identified risks, or byusing a visual representations of fuzzy regions rather than points).

29

Security categorizations conducted in accordance with FIPS Publication 199 provide examples of worst-case impact
analyses (using the high water mark concept). This type of impact analysis provides an upper bound for risk whenapplied to discrete situations within organizations.

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2.3.2 Assessment Approaches
Risk, and its contributing factors, can be assessed in a variety of ways, including quantitatively,
qualitatively, or semi-quantitatively. Each risk assessment approach considered by organizations
has advantages and disadvantages. A preferred approach (or situation-specific set of approaches)
can be selected based on organizational culture and, in particular, attitudes toward the concepts ofuncertainty and risk communication. Quantitative assessments typically employ a set of methods,
principles, or rules for assessing risk based on the use of numbers—where the meanings andproportionality of values are maintained inside and outside the context of the assessment. This
type of assessment most effectively supports cost-benefit analyses of alternative risk responses orcourses of action. However, the meaning of the quantitative results may not always be clear andmay require interpretation and explanation—particularly to explain the assumptions andconstraints on using the results. For example, organizations may typically ask if the numbers or
results obtained in the risk assessments are reliable or if the differences in the obtained values aremeaningful or insignificant. Additionally, the rigor of quantification is significantly lessened
when subjective determinations are buried within the quantitative assessments, or whensignificant uncertainty surrounds the determination of values. The benefits of quantitative
assessments (in terms of the rigor, repeatability, and reproducibility of assessment results) can, insome cases, be outweighed by the costs (in terms of the expert time and effort and the possible
deployment and use of tools required to make such assessments).
In contrast to quantitative assessments, qualitative assessments typically employ a set of methods,
principles, or rules for assessing risk based on nonnumerical categories or levels (e.g., very low,
low, moderate, high, very high). This type of assessment supports communicating risk results todecision makers. However, the range of values in qualitative assessments is comparatively small
in most cases, making the relative prioritization or comparison within the set of reported risks
difficult. Additionally, unless each value is very clearly defined or is characterized by meaningful
examples, different experts relying on their individual experiences could produce significantly
different assessment results. The repeatability and reproducibility of qualitative assessments are
increased by the annotation of assessed values (e.g., this value is high because of the following
reasons) and by the use of tables or other well-defined functions to combine qualitative values.
Finally, semi-quantitative assessments typically employ a set of methods, principles, or rules forassessing risk that uses bins, scales, or representative numbers whose values and meanings are notmaintained in other contexts. This type of assessment can provide the benefits of quantitative andqualitative assessments. The bins (e.g., 0-15, 16-35, 36-70, 71-85, 86-100) or scales (e.g., 1-10)translate easily into qualitative terms that support risk communications for decision makers (e.g.,a score of 95 can be interpreted as very high), while also allowing relative comparisons between
values in different bins or even within the same bin (e.g., the difference between risks scored 70
and 71 respectively is relatively insignificant, while the difference between risks scored 36 and 70
is relatively significant). The role of expert judgment in assigning values is more evident than in apurely quantitative approach. Moreover, if the scales or sets of bins provide sufficient granularity,
relative prioritization among results is better supported than in a purely qualitative approach. As
in a quantitative approach, rigor is significantly lessened when subjective determinations areburied within assessments, or when significant uncertainty surrounds a determination of value. As
with the nonnumeric categories or levels used in a well-founded qualitative approach, each bin or
range of values needs to be clearly defined and/or characterized by meaningful examples.
Independent of the type of value scale selected, assessments make explicit the temporal elementof risk factors. For example, organizations can associate a specific time period with assessmentsof likelihood of occurrence and assessments of impact severity.

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2.3.3 Analysis Approaches
Analysis approaches differ with respect to the orientation or starting point of the risk assessment,
level of detail in the assessment, and how risks due to similar threat scenarios are treated. An
analysis approach can be: (i) threat-oriented; (ii) asset/impact-oriented; or (iii) vulnerabilityoriented. 30 A threat-oriented approach starts with the identification of threat sources and threat
events, and focuses on the development of threat scenarios; vulnerabilities are identified in thecontext of threats, and for adversarial threats, impacts are identified based on adversary intent. An
asset/impact-oriented approach starts with the identification of impacts or consequences ofconcern and critical assets, possibly using the results of a mission or business impact analyses 31
and identifying threat events that could lead to and/or threat sources that could seek those impacts
or consequences. A vulnerability-oriented approach starts with a set of predisposing conditions or
exploitable weaknesses/deficiencies in organizational information systems or the environments inwhich the systems operate, and identifies threat events that could exercise those vulnerabilities
together with possible consequences of vulnerabilities being exercised. Each analysis approachtakes into consideration the same risk factors, and thus entails the same set of risk assessment
activities, albeit in different order. Differences in the starting point of the risk assessment canpotentially bias the results, causing some risks not to be identified. Therefore, identification ofrisks from a second orientation (e.g., complementing a threat-oriented analysis approach with anasset/impact-oriented analysis approach) can improve the rigor and effectiveness of the analysis.
In addition to the orientation of the analysis approach, organizations can apply more rigorous
analysis techniques (e.g., graph-based analyses) to provide an effective way to account for the
many-to-many relationships between: (i) threat sources and threat events (i.e., a single threat
event can be caused by multiple threat sources and a single threat source can cause multiple threat
events); (ii) threat events and vulnerabilities (i.e., a single threat event can exploit multiple
vulnerabilities and a single vulnerability can be exploited by multiple threat events); and (iii)threat events and impacts/assets (i.e., a single threat event can affect multiple assets or havemultiple impacts, and a single asset can be affected by multiple threat events). 32 Rigorous analysis
approaches also provide a way to account for whether, in the time frame for which risks areassessed, a specific adverse impact could occur (or a specific asset could be harmed) at mostonce, or perhaps repeatedly, depending on the nature of the impacts and on how organizations(including mission/business processes or information systems) recover from such adverse
impacts.

30
Organizations have great flexibility in choosing a particular analysis approach. The specific approach taken is driven
by different organizational considerations (e.g., the quality and quantity of information available with respect to threats,vulnerabilities, and impacts/assets; the specific orientation carrying the highest priority for organizations; availability ofanalysis tools emphasizing certain orientations; or a combination of the above).
31
A Business Impact Analysis (BIA) identifies high-value assets and adverse impacts with respect to the loss of
integrity or availability. DHS Federal Continuity Directive 2 provides guidance on BIAs at the organization andmission/business process levels of the risk management hierarchy, respectively. NIST Special Publication 800-34
provides guidance on BIAs at the information system level of the risk management hierarchy.
32

For example, graph-based analysis techniques (e.g., functional dependency network analysis, attack tree analysis foradversarial threats, fault tree analysis for other types of threats) provide ways to use specific threat events to generatethreat scenarios. Graph-based analysis techniques can also provide ways to account for situations in which one event
can change the likelihood of occurrence for another event. Attack and fault tree analyses, in particular, can generate
multiple threat scenarios that are nearly alike, for purposes of determining the levels of risk. With automated modelingand simulation, large numbers of threat scenarios (e.g., attack/fault trees, traversals of functional dependency networks)
can be generated. Thus, graph-based analysis techniques include ways to restrict the analysis to define a reasonable
subset of all possible threat scenarios.

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2.3.4 Effects of Organizational Culture on Risk Assessments
Organizations can differ in the risk models, assessment approaches, and analysis approaches thatthey prefer for a variety of reasons. For example, cultural issues 33 can predispose organizations toemploy risk models that assume a constant value for one or more possible risk factors, so thatsome factors that are present in other organizations’ models are not represented. Culture can also
predispose organizations to employ risk models that require detailed analyses using quantitative
assessments (e.g., nuclear safety). Alternately, organizations may prefer qualitative or semiquantitative assessment approaches. In addition to differences among organizations, differences
can also exist within organizations. For example, organizations can use coarse or high-level risk
models early in the system development life cycle to select security controls, and subsequently,
more detailed models to assess risk to given missions or business functions. Organizational risk
frames 34 determine which risk models, assessment approaches, and analysis approaches to use
under varying circumstances.

THE USE OF RISK MODELS
A single risk model (consisting of a fixed set of factors, a fixed assessment scale for each factor, and afixed algorithm for combining factors) cannot meet the diverse needs of the organizations in the public
and private sectors that rely on Special Publication 800-30. For example, while some organizations mayemphasize adversarial threats and provide detailed information about such threats, other organizations
may choose instead to focus on non-adversarial threats, providing greater detail for those types of
threats and lesser detail for adversarial threats. Therefore, the risk models developed by organizations
with different assumptions regarding threats will involve different factors as well as different levels ofdetail.
Similarly, within a single organization or community of interest, different assessment scales may beappropriate for different missions/business functions, different categories of information systems, and/or
for systems at different stages in the system development life cycle. For example, during an initial risk
assessment performed when an information system is first being considered, the information available
about threats and vulnerabilities may be nonspecific and highly uncertain. For such risk assessments, aqualitative assessment, using only a few factors, may be appropriate. By contrast, a risk assessment
informed by a security controls assessment can be far more specific, and estimates can be made withgreater fidelity. For such assessments, a semi-quantitative assessment using the 0-100 value scales
may be more appropriate.
The expectation set forth in Special Publications 800-39 and 800-30 is that each organization orcommunity will define a risk model appropriate to its view of risk (i.e., formulas that reflect organizationalor community views of which risk factors must be considered, which factors can be combined, which
factors must be further decomposed, and how assessed values should be combined algorithmically).
Special Publication 800-30 does identify risk factors that are common across a wide spectrum of risk
models. In addition, by defining multiple aligned value scales, this publication provides a foundation for aconsistent approach to estimating information security risk across the system development life cycle,
without forcing assessments early in the life cycle to be more detailed than can be justified by available
information.

33

NIST Special Publication 800-39 describes how organizational culture affects risk management.

34

NIST Special Publication 800-39 defines an organization’s risk frame as the set of assumptions, constraints, risk
tolerances, priorities, and trade-offs that underpin the organization’s risk management strategy—establishing a solid
foundation for managing risk and bounding its risk-based decisions.

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2.4 APPLICATION OF RISK ASSESSMENTS
As stated previously, risk assessments can be conducted at all three tiers in the risk management
hierarchy—organization level, mission/business process level, and information system level.
Figure 4 illustrates the risk management hierarchy defined in NIST Special Publication 800-39,
which provides multiple risk perspectives from the strategic level to the tactical level. Traditionalrisk assessments generally focus at the Tier 3 level (i.e., information system level) and as a result,tend to overlook other significant risk factors that may be more appropriately assessed at the Tier
1 or Tier 2 levels (e.g., exposure of a core mission/business function to an adversarial threat basedon information system interconnections).
STRATEGIC RISK
- Traceability and Transparency of
Risk-Based Decisions- Organization-Wide
Risk Awareness

TIER 1ORGANIZATION- Inter-Tier and Intra-Tier
Communications- Feedback Loop forContinuous Improvement

TIER 2MISSION / BUSINESS PROCESSESTIER 3

INFORMATION SYSTEMSTACTICAL RISKFIGURE 4: RISK MANAGEMENT HIERARCHY

Risk assessments support risk response decisions at the different tiers of the risk management
hierarchy. At Tier 1, risk assessments can affect, for example: (i) organization-wide information
security programs, policies, procedures, and guidance; (ii) the types of appropriate risk responses(i.e., risk acceptance, avoidance, mitigation, sharing, or transfer); (iii) investment decisions for
information technologies/systems; (iv) procurements; (v) minimum organization-wide security
controls; (vi) conformance to enterprise/security architectures; and (vii) monitoring strategies andongoing authorizations of information systems and common controls. At Tier 2, risk assessments
can affect, for example: (i) enterprise architecture/security architecture design decisions; (ii) the
selection of common controls; (iii) the selection of suppliers, services, and contractors to support
organizational missions/business functions; (iv) the development of risk-aware mission/businessprocesses; and (v) the interpretation of information security policies with respect to organizational
information systems and environments in which those systems operate. Finally, at Tier 3, risk
assessments can affect, for example: (i) design decisions (including the selection, tailoring, andsupplementation of security controls and the selection of information technology products fororganizational information systems); (ii) implementation decisions (including whether specificinformation technology products or product configurations meet security control requirements);
and (iii) operational decisions (including the requisite level of monitoring activity, the frequency
of ongoing information system authorizations, and system maintenance decisions).

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Risk assessments can also inform other risk management activities across the three tiers that are
not security-related. For example, at Tier 1, risk assessments can provide useful inputs to: (i)operational risk determinations (including business continuity for organizational missions andbusiness functions); (ii) organizational risk determinations (including financial risk, compliancerisk, regulatory risk, reputation risk, and cumulative acquisition risk across large-scale projects);and (iii) multiple-impact risk (including supply chain risk and risk involving partnerships). At
Tier 2, risk assessments can provide the same useful inputs to operational, organizational, andmultiple-impact risks, specific to mission/business processes. At Tier 3, risk assessments caninform assessments of cost, schedule, and performance risks associated with information systems,with information security experts coordinating with program managers, information systemowners, and authorizing officials. This type of coordination is essential within organizations inorder to eliminate silos and/or stove-piped activities that produce less than optimal or inefficient
information technology and security solutions—thus affecting the ability of organizations to carryout assigned missions/business functions with maximum efficiency and cost-effectiveness.
It is important to note that information security risk contributes to non-security risks at each tier.
Thus, the results of a risk assessment at a given tier serve as inputs to, and are aligned with, nonsecurity risk management activities at that tier. 35 In addition, the results of risk assessments atlower tiers serve as inputs to risk assessments at higher tiers. Risks can arise on different timescales (e.g., the disclosure of information about current organizational operations can compromise
the effectiveness of those operations immediately, while the disclosure of strategic planning
information can compromise future operational capabilities). Risk response decisions can also
take effect in different time frames (e.g., changes in organizational policies or investment
strategies can sometimes require years to take effect, while configuration changes in an individual
system can often be implemented immediately). In general, the risk management process tends tomove more slowly at Tiers 1 and 2 than at Tier 3. This is due to how organizations typically
respond to risks that potentially affect widespread organizational operations and assets—wheresuch risk responses may need to address systemic or institutional issues. However, some Tier 1
decisions (e.g., newly discovered threats or vulnerabilities requiring the implementation of anorganization-wide mandate for mitigation) can involve immediate action.
2.4.1

Risk Assessments at the Organizational Tier

At Tier 1, risk assessments support organizational strategies, policies, guidance, and processes for
managing risk. Risk assessments conducted at Tier 1 focus on organizational operations, assets,
and individuals—comprehensive assessments across mission/business lines. For example, Tier 1
risk assessments may address: (i) the specific types of threats directed at organizations that may
be different from other organizations and how those threats affect policy decisions; (ii) systemic
weaknesses or deficiencies discovered in multiple organizational information systems capable ofbeing exploited by adversaries; (iii) the potential adverse impact on organizations from the loss orcompromise of organizational information (either intentionally or unintentionally); and (iv) theuse of new information and computing technologies such as mobile and cloud and the potential
effect on the ability of organizations to successfully carry out their missions/business operations
while using those technologies. Organization-wide assessments of risk can be based solely on theassumptions, constraints, risk tolerances, priorities, and trade-offs established in the risk framing
step (i.e., derived primarily from Tier 1 activities). However, more realistic and meaningful risk
assessments are based on assessments conducted across multiple mission/business lines (i.e.,
derived primarily from Tier 2 activities). The ability of organizations to effectively use Tier 2 risk
35
In particular, risk assessment results support investment risk management. NIST Special Publication 800-65 provides
guidance on integrating information security into the Capital Planning and Investment Control (CPIC) process.

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assessments as inputs to Tier 1 risk assessments is shaped by such considerations as: (i) thesimilarity of organizational missions/business functions and mission/business processes; and (ii)the degree of autonomy that organizational entities or subcomponents have with respect to parent
organizations. In decentralized organizations or organizations with varied missions/business
functions and/or environments of operation, expert analysis may be needed to normalize theresults from Tier 2 risk assessments. Finally, risk assessments at Tier 1 take into consideration theidentification of mission-essential functions from Continuity of Operations Plans (COOP) 36
prepared by organizations when determining the contribution of Tier 2 risks. Risk assessment
results at Tier 1 are communicated to organizational entities at Tier 2 and Tier 3.
2.4.2

Risk Assessments at the Mission/Business Process Tier

At Tier 2, risk assessments support the determination of mission/business process protection andresiliency requirements, and the allocation of those requirements to the enterprise architecture aspart of mission/business segments (that support mission/business processes). This allocation isaccomplished through an information security architecture embedded within the enterprisearchitecture. Tier 2 risk assessments also inform and guide decisions on whether, how, and when
to use information systems for specific mission/business processes, in particular for alternative
mission/business processing in the face of compromised information systems. Risk management
and associated risk assessment activities at Tier 2 are closely aligned with the development of
Business Continuity Plans (BCPs). Tier 2 risk assessments focus on mission/business segments,
which typically include multiple information systems, with varying degrees of criticality and/or
sensitivity with regard to core organizational missions/business functions. 37 Risk assessments at
Tier 2 can also focus on information security architecture as a critical component of enterprisearchitecture to help organizations select common controls inherited by organizational information
systems at Tier 3. Risk assessment results produced at Tier 2 are communicated to and sharedwith organizational entities at Tier 3 to help inform and guide the allocation of security controls
to information systems and environments in which those systems operate. Tier 2 risk assessments
also provide assessments of the security and risk posture of organizational mission/businessprocesses, which inform assessments of organizational risks at Tier 1. Thus, risk assessment
results at Tier 2 are routinely communicated to organizational entities at Tier 1 and Tier 3.
2.4.3

Risk Assessments at the Information System Tier

The Tier 2 context and the system development life cycle determine the purpose and define thescope of risk assessment activities at Tier 3. While initial risk assessments (i.e., risk assessments
performed for the first time, rather than updating prior risk assessments) can be performed at any
phase in the system development life cycle, ideally these assessments should be performed in theInitiation phase.38 In the Initiation phase, risk assessments evaluate the anticipated vulnerabilities
and predisposing conditions affecting the confidentiality, integrity, and availability of information
systems in the context of the planned environments of operation. Such assessments inform risk
response, enabling information system owners/program managers, together with mission/businessowners to make the final decisions about the security controls necessary based on the security
categorization and the environment of operation. Risk assessments are also conducted at later
phases in the system development life cycle, updating risk assessment results from earlier phases.
These risk assessment results for as-built or as-deployed information systems typically include
36

NIST Special Publication 800-34 provides guidance on Information System Contingency Planning (ISCP).

37

The criticality of information systems to organizational missions/business functions may be identified in Business
Impact Analyses.
38

NIST Special Publication 800-64 provides guidance for security considerations in the system development life cycle.

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descriptions of vulnerabilities in the systems, an assessment of the risks associated with eachvulnerability (thereby updating the assessment of vulnerability severity), and corrective actions
that can be taken to mitigate the risks. The risk assessment results also include an assessment of
the overall risk to the organization and the information contained in the information systems by
operating the systems as evaluated. Risk assessment results at Tier 3 are communicated toorganizational entities at Tier 1 and Tier 2.
Risk assessment activities can be integrated with the steps in the Risk Management Framework(RMF), as defined in NIST Special Publication 800-37. The RMF, in its system development life
cycle approach, operates primarily at Tier 3 with some application at Tiers 1 and 2, for example,
in the selection of common controls. Risk assessments can be tailored to each step in the RMF asreflected in the purpose and scope of the assessments described in Section 3.1. Risk assessments
can also help determine the type of security assessments conducted during various phases of thesystem development life cycle, the frequency of such assessments, the level of rigor applied
during the assessments, the assessment methods used, and the types/number of objects assessed.
The benefit of risk assessments conducted as part of the RMF can be realized from both initialassessments and from updated assessments, as described below.
RMF Step 1 – Categorize
Organizations can use initial risk assessments to make security categorization decisions consistent
with the risk management strategy provided by the risk executive (function) and as a preparatory
step to security control selection. Conducting initial risk assessments brings together the available
information on threat sources, threat events, vulnerabilities, and predisposing conditions—thus
enabling organizations to use such information to categorize information and information systems
based on known and potential threats to and vulnerabilities in organizational information systems
and environments in which those systems operate. 39 Security categorization decisions inform theselection of initial baseline security controls. Baseline security controls serve as the starting point
for organizational tailoring and supplementation activities described in the RMF Select step.
RMF Step 2 – SelectOrganizations can use risk assessments to inform and guide the selection of security controls fororganizational information systems and environments of operation. After the initial security
control baseline is selected based on the security categorization process, the risk assessment
results help organizations: (i) apply appropriate tailoring guidance to adjust the controls based on
specific mission/business requirements, assumptions, constraints, priorities, trade-offs, or otherorganization-defined conditions; and (ii) supplement the controls based on specific and credible
threat information. 40 Threat data from risk assessments provide critical information on adversarycapabilities, intent, and targeting that may affect the decisions by organizations regarding theselection of additional security controls including the associated costs and benefits. Organizations
also consider risk assessment results when selecting common controls (typically a Tier 1 and Tier
2 activity). Risk is introduced if the implementation of a common control results in a single pointof failure because the control provides a security capability potentially inherited by multiple
information systems. As risk assessments are updated and refined, organizations use the results tomodify current security control selections based on the most recent threat and vulnerability
information available.
39
Even when an initial risk assessment is performed prior to the existence of an information system, vulnerabilities
may be present in certain technologies that will be used in the system, in common controls that will be inherited by thesystem, or in the environment in which the system will operate.
40

Supplementation will be incorporated into the tailoring process in NIST Special Publication 800-53, Revision 4.

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Organizations can use risk assessment results to identify alternative implementations of selected
security controls (e.g., considering vulnerabilities inherent in one security control implementation
versus another). Some information technology products, system components, or architecturalconfigurations may be more susceptible to certain types of threat sources; these susceptibilities
are subsequently addressed during security control development and implementation. In addition,
the strength of security mechanisms selected for implementation can take into consideration thethreat data from risk assessments. Individual configuration settings for information technology
products and system components can eliminate vulnerabilities identified during the analysis ofthreat events. Risk assessment results also help inform decisions regarding the cost, benefit, andrisk trade-offs in using one type of technology versus another or how security controls are
effectively implemented in particular operational environments (e.g., when compensating controls
must be used due to the unavailability of certain technologies). As risk assessments are updated
and refined, organizations use the results to help determine if current security control
implementations remain effective given changes to the threat space.
RMF Step 4 – Assess
Organizations can use the results from security control assessments to inform risk assessments.
Security control assessments (documented in security assessment reports) identify vulnerabilities
in organizational information systems and the environments in which those systems operate.
Partial or complete failure of deployed security controls or the absence of planned controls
represents potential vulnerabilities that can be exploited by threat sources. Organizations use theresults from risk assessments to help determine the severity of such vulnerabilities which in turn,can guide and inform organizational risk responses (e.g., prioritizing risk response activities,
establishing milestones for corrective actions).
RMF Step 5 – Authorize
Organizations can use risk assessment results to provide risk-related information to authorizing
officials. The risk responses carried out by organizations based on the risk assessments result in a
known security posture of organizational information systems and environments of operation.
Risk assessment results provide essential information to enable authorizing officials to make riskbased decisions on whether to operate those systems in the current security posture or take actions
to provide additional security controls, thereby further reducing risk to organizational operations
and assets, individuals, other organizations, or the Nation.
RMF Step 6 – Monitor
Organizations can update risk assessments on an ongoing basis using security-related informationfrom organizational continuous monitoring processes. 41 Continuous monitoring processes
evaluate: (i) the effectiveness of security controls; (ii) changes to information systems andenvironments of operation; and (iii) compliance to federal legislation, regulations, directives,
policies, standards, and guidance. As risk assessments are updated and refined, organizations use
the results to update the risk management strategy, thereby incorporating lessons learned into risk
management processes, improving responses to risk, and building a solid foundation of threat andvulnerability information tailored to organizational missions/business functions.

41

NIST Special Publication 800-137 provides guidance on information security continuous monitoring for information
systems and organizations.

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2.4.4

Risk Communications and Information Sharing

The risk assessment process entails ongoing communications and information sharing among
stakeholders to ensure that: (i) the inputs to such assessments are as accurate as possible; (ii)intermediate assessment results can be used, for example, to support risk assessments at othertiers; and (iii) the results are meaningful and useful inputs to the risk response step in the risk
management process. The manner and form in which risks are communicated are an expressionof organizational culture as well as legal, regulatory, and contractual constraints. To be effective,
communication of information security risks and other risk-related information produced during
the risk assessment is consistent with other forms of risk communication within organizations. To
maximize the benefit of risk assessments, organizations should establish policies, procedures, andimplementing mechanisms to ensure that the information produced during such assessments is
effectively communicated and shared across all three risk management tiers. 42 To reinforce theimportance of risk communication and information sharing within organizations, the input tables
in Appendices D, E, F, G, H, and I (i.e., threat sources, threat events, vulnerabilities, predisposing
conditions, likelihood, impact, and risk) and the recommended elements of a risk assessment
report (Appendix K) provide recommendations for risk communication/sharing among the tiers.

TARGETED RISK ASSESSMENTS
Organizations can use targeted risk assessments, in which the scope is narrowly defined, to produce
answers to specific questions (e.g., what is the risk associated with relying on a given technology, howshould prior assessments of risk be revised based on incidents that have occurred, what new risks canbe identified based on knowledge about a newly discovered threat or vulnerability) or to inform specificdecisions (e.g., which risks should be managed at Tier 1 rather than Tier 2 or 3). Organizations may
consider assessing risk at Tier 1 and Tier 2 arising from a set of common threats and vulnerabilities
applicable to a wide range of organizational information systems. Assessing risk at Tiers 1 and 2 allows
organizations to reduce the number of threats and vulnerabilities considered at the individual information
system level and develop common risk responses for such organization-wide risks. This approach cansupport the common control selection process for organizations and increase the efficiency and costeffectiveness of risk assessments across the organization.
With respect to all three tiers in the risk management hierarchy, there are no specific requirementswith regard to: (i) the formality, rigor, or level of detail that characterizes any particular risk assessment;(ii) the methodologies, tools, and techniques used to conduct such risk assessments; or (iii) the format
and content of assessment results and any associated reporting mechanisms. Organizations havemaximum flexibility on how risk assessments are conducted, where such assessments are applied,and how the results will be used. Organizations are encouraged to use the guidance in a manner thatmost effectively and cost-effectively provides the information necessary to senior leaders/executives tofacilitate informed risk management decisions.

42
NIST Special Publications 800-117 and 800-126 provide guidance on the Security Content Automation Protocol(SCAP) program. The SCAP program provides a standard, consistent way to communicate threat and vulnerability
information.

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CHAPTER THREE

THE PROCESSCONDUCTING RISK ASSESSMENTS WITHIN ORGANIZATIONST

his chapter describes the process of assessing information security risk including: (i) ahigh-level overview of the risk assessment process; (ii) the activities necessary to prepare
for risk assessments; (iii) the activities necessary to conduct effective risk assessments;(iv) the activities necessary to communicate the assessment results and share risk-related
information; and (v) the activities necessary to maintain the results of risk assessments on an
ongoing basis. The risk assessment process 43 is composed of four steps: (i) prepare for theassessment; (ii) conduct the assessment; (iii) communicate assessment results; and (iv) maintainthe assessment. 44 Each step is divided into a set of tasks. For each task, supplemental guidance
provides additional information for organizations conducting risk assessments. Risk tables andexemplary assessment scales are listed in appropriate tasks and cross-referenced to additional,
more detailed information in the supporting appendices. Figure 5 illustrates the basic steps in therisk assessment process and highlights the specific tasks for conducting the assessment.

Step 1: Prepare for Assessment
Derived from Organizational Risk Frame

Step 2: Conduct Assessment
Identify Threat Sources and Events

Identify Vulnerabilities andPredisposing Conditions

Determine Likelihood of Occurrence

Determine Magnitude of Impact

Step 4: Maintain Assessment

Step 3: Communicate Results

Expanded Task View

Determine Risk

FIGURE 5: RISK ASSESSMENT PROCESS
43
The intent of the process description in Chapter Three is to provide a common expression of the essential elements ofan effective risk assessment. It is not intended to limit organizational flexibility in conducting those assessments. Other
procedures can be implemented if organizations choose to do so, consistent with the intent of the process description.
44

The four-step risk assessment process described in this publication is consistent with the general risk assessment
process described in NIST Special Publication 800-39. The additional steps and tasks result from the need to provide
more detailed guidance to effectively carry out the specific activities associated with risk assessments.

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3.1 PREPARING FOR THE RISK ASSESSMENT
The first step in the risk assessment process is to prepare for the assessment. The objective of thisstep is to establish a context for the risk assessment. This context is established and informed by
the results from the risk framing step of the risk management process. Risk framing identifies, forexample, organizational information regarding policies and requirements for conducting risk
assessments, specific assessment methodologies to be employed, procedures for selecting risk
factors to be considered, scope of the assessments, rigor of analyses, degree of formality, andrequirements that facilitate consistent and repeatable risk determinations across the organization.
Organizations use the risk management strategy to the extent practicable to obtain information toprepare for the risk assessment. Preparing for a risk assessment includes the following tasks:•

Identify the purpose of the assessment;•

Identify the scope of the assessment;•

Identify the assumptions and constraints associated with the assessment;•

Identify the sources of information to be used as inputs to the assessment; and•Identify the risk model and analytic approaches (i.e., assessment and analysis approaches) tobe employed during the assessment.

STEP 1: PREPARE FOR THE ASSESSMENTIDENTIFY PURPOSETASK 1-1: Identify the purpose of the risk assessment in terms of the information that the assessment isintended to produce and the decisions the assessment is intended to support.
Supplemental Guidance: The purpose of the risk assessment is explicitly stated in sufficient detail to ensure that theassessment produces the appropriate information and supports the intended decisions. Organizations can provide
guidance on how to capture and present information produced during the risk assessment (e.g., using a definedorganizational template). Appendix K provides an exemplary template for a risk assessment report or the preferredvehicle for risk communication. At Tier 3, risk assessments support: (i) authorization-related decisions throughout thesystem development life cycle; (ii) reciprocity, particularly for reuse of assessment information; (iii) risk management
activities at Tier 2; and (iv) programmatic risk management activities throughout the system development life cycle. At
Tier 2, risk assessments enable organizations to: (i) understand dependencies and ways in which risks are accepted,
rejected, shared, transferred, or mitigated among information systems that support organizational mission/businessprocesses; (ii) support architectural and operational decisions for organizational risk responses (e.g., reducing
dependencies, limiting connectivity, enhancing or focusing monitoring, and enhancing information/system resiliency);(iii) identify trends, so that proactive risk response strategies and courses of action for mission/business processes canbe defined; and (iv) support reciprocity, particularly to enable information sharing. At Tier 1, risk assessments: (i)support the risk executive (function); and (ii) serve as a key input to the risk management strategy. In addition to thesecommon purposes, risk assessments may have a very specific purpose, to answer a specific question (e.g., What are therisk implications of a newly discovered vulnerability or class of vulnerabilities, allowing new connectivity, outsourcing
a specific function, or adopting a new technology?). Risk assessment results from all tiers can be used by organizations
to inform the acquisition process by helping to ensure information security requirements are clearly specified.
The purpose of the risk assessment is influenced by whether the assessment is: (i) an initial assessment; or (ii) a
subsequent assessment initiated from the risk response or monitoring steps in the risk management process. For initialassessments, the purpose can include, for example: (i) establishing a baseline assessment of risk; or (ii) identifying
threats and vulnerabilities, impacts to organizational operations and assets, individuals, other organizations, and the
Nation, and other risk factors to be tracked over time as part of risk monitoring. For a reassessment initiated from therisk response step, the purpose can include, for example, providing a comparative analysis of alternative risk responses
or answering a specific question (see discussion of targeted risk assessments above). Alternatively, for a reassessment
initiated from the risk monitoring step, the purpose can include, for example, updating the risk assessment based on: (i)ongoing determinations of the effectiveness of security controls in organizational information systems or environmentsof operation; (ii) changes to information systems or environments of operation (e.g., changes to hardware, firmware,
software; changes to system-specific, hybrid, or common controls; changes to mission/business processes, common

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infrastructure and support services, threats, vulnerabilities, or facilities); and (iii) results from compliance verification
activities. Reassessments can also be initiated by organizations due to incidents that have occurred (e.g., cyber attacks
compromising organizational information or information systems).
IDENTIFY SCOPETASK 1-2: Identify the scope of the risk assessment in terms of organizational applicability, time frame

supported, and architectural/technology considerations.
Supplemental Guidance: The scope of the risk assessment determines what will be considered in the assessment. Risk
assessment scope affects the range of information available to make risk-based decisions and is determined by theorganizational official requesting the assessment and the risk management strategy. Establishing the scope of the risk
assessment helps organizations to determine: (i) what tiers are addressed in the assessment; (ii) what parts oforganizations are affected by the assessment and how they are affected; (iii) what decisions the assessment results
support; (iv) how long assessment results are relevant; and (v) what influences the need to update the assessment.
Establishing the scope of the risk assessment helps to determine the form and content of the risk assessment report, as
well as the information to be shared as a result of conducting the assessment. At Tier 3, the scope of a risk assessment
can depend on the authorization boundary for the information system. Appendix K provides an example of the type of
information that may be included in a risk assessment report or the preferred vehicle for risk communication.
Organizational Applicability
Organizational applicability describes which parts of the organization or suborganizations are affected by the risk
assessment and the risk-based decisions resulting from the assessment (including the parts of the organization or
suborganizations responsible for implementing the activities and tasks related to the decisions). For example, the risk
assessment can inform decisions regarding information systems supporting a particular organizational mission/business
function or mission/business process. This can include decisions regarding the selection, tailoring, or supplementationof security controls for specific information systems or the selection of common controls. Alternatively, the risk
assessment can inform decisions regarding a set of closely related missions/business functions or mission/businessprocesses. The scope of the risk assessment can include not only the missions/business functions, mission/businessprocesses, common infrastructure, or shared services on which the organization currently depends, but also those which
the organization might use under specific operational conditions.
Effectiveness Time Frame
Organizations determine how long the results of particular risk assessments can be used to legitimately inform riskbased decisions. The time frame is usually related to the purpose of the assessment. For example, a risk assessment to
inform Tier 1 policy-related decisions needs to be relevant for an extended period of time since the governance process
for policy changes can be time-consuming in many organizations. A risk assessment conducted to inform a Tier 3
decision on the use of a compensating security control for an information system may be relevant only until the next
release of the information technology product providing the required security capability. Organizations determine theuseful life of risk assessment results and under what conditions the current assessment results become ineffective or
irrelevant. Risk monitoring can be used to help determine the effectiveness of time frames for risk assessments. In
addition to risk assessment results, organizations also consider the currency/timeliness (i.e., latency or age) of all typesof information/data used in assessing risk. This is of particular concern in information reuse and evaluating the validityof assessment results.
Architectural/Technology Considerations
Organizations use architectural and technology considerations to clarify the scope of the risk assessment. For example,
at Tier 3, the scope of the risk assessment can be an organizational information system in its environment of operations.
This entails placing the information system in its architectural context, so that vulnerabilities in inherited controls canbe taken into consideration. Alternately, the scope of the assessment can be limited solely to the information system,without consideration of inherited vulnerabilities. At Tier 2, the scope of the risk assessment can be defined in terms ofthe mission/business segment architecture (e.g., including all systems, services, and infrastructures that support a
specific mission/function). For a targeted risk assessment at any tier, the specific question to be answered can restrict
the scope to a specific technology.
IDENTIFY ASSUMPTIONS AND CONSTRAINTSTASK 1-3: Identify the specific assumptions and constraints under which the risk assessment is conducted.
Supplemental Guidance: As part of the risk framing step in the risk management process, organizations make explicit
the specific assumptions, constraints, risk tolerance, and priorities/trade-offs used within organizations to makeinvestment and operational decisions. This information guides and informs organizational risk assessments. When an
organizational risk management strategy cannot be cited, risk assessments identify and document assumptions andconstraints. Assumptions and constraints identified by organizations during the risk framing step and included as part

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assumptions and constraints explicit, there is greater clarity in the risk model selected for the risk assessment, increased
reproducibility/repeatability of assessment results, and an increased opportunity for reciprocity among organizations.
Organizations identify assumptions in key areas relevant to the risk assessment including, for example: (i) threatsources; (ii) threat events; (iii) vulnerabilities and predisposing conditions; (iv) potential impacts; (v) assessment andanalysis approaches; and (vi) which missions/business functions are primary. Organizations also identify constraints in
key areas relevant to the risk assessment including, for example: (i) resources available for the assessment; (ii) skills
and expertise required for the assessment; and (iii) operational considerations related to mission/business activities. For
example, organizational assumptions about how threats and impacts should be assessed can range from using worstcase projections to using best-case projections or anything in between those endpoints. Finally, organizations consider
the uncertainty with regard to assumptions made or other information used in the risk assessment. Uncertainty inassumptions can affect organizational risk tolerance. For example, assumptions based on a lack of specific or credible
information may reduce an organization’s risk tolerance because of the uncertainty influencing the assumptions. The
following sections provide some representative examples of areas where assumptions/constraints for risk assessments
may be identified.
Threat Sources
Organizations determine which types of threat sources are to be considered during risk assessments. Organizations
make explicit the process used to identify threats and any assumptions related to the threat identification process. If
such information is identified during the risk framing step and included as part of the organizational risk management
strategy, the information need not be repeated in each individual risk assessment. Risk assessments can address all
types of threat sources, a single broad threat source (e.g., adversarial), or a specific threat source (e.g., trusted insider).
Table D-2 provides a sample taxonomy of threat sources that can be considered by organizations in identifying
assumptions for risk assessments. Organizational assumptions about threat sources to consider inform Task 2-1.
Threat Events
Organizations determine which type of threat events are to be considered during risk assessments and the level of detailneeded to describe such events. Descriptions of threat events can be expressed in highly general terms (e.g., phishing,
distributed denial-of-service), in more descriptive terms using tactics, techniques, and procedures, or in highly specificterms (e.g., the names of specific information systems, technologies, organizations, roles, or locations). In addition,organizations consider: (i) what representative set of threat events can serve as a starting point for the identification of
the specific threat events in the risk assessment; and (ii) what degree of confirmation is needed for threat events to beconsidered relevant for purposes of the risk assessment. For example, organizations may consider only those threat
events that have been observed (either internally or by organizations that are peers/partners) or all possible threat
events. Table E-2 and Table E-3 provide representative examples of adversarial and non-adversarial threat events at alevel of detail that can be used for risk assessments at all tiers. Greater detail can be found in multiple sources (e.g.,Common Attack Pattern Enumeration and Classification [CAPEC]). Organizational assumptions about threat events toconsider and level of detail, inform Task 2-2.
Vulnerabilities and Predisposing Conditions
Organizations determine the types of vulnerabilities that are to be considered during risk assessments and the level ofdetail provided in the vulnerability descriptions. Organizations make explicit the process used to identify vulnerabilities
and any assumptions related to the vulnerability identification process. If such information is identified during the risk
framing step and included as part of the organizational risk management strategy, the information need not be repeatedin each individual risk assessment. Vulnerabilities can be associated with organizational information systems (e.g.,
hardware, software, firmware, internal controls, and security procedures) or the environments in which those systems
operate (e.g., organizational governance, external relationships, mission/business processes, enterprise architectures,information security architectures). Organizations also determine the types of predisposing conditions that are to beconsidered during risk assessments including, for example, architectures and technologies employed, environments ofoperation, and personnel. Table F-4 provides representative examples of such predisposing conditions. Organizational
assumptions about vulnerabilities and predisposing conditions to consider and level of detail, inform Task 2-3.
Likelihood
Organizations make explicit the process used to conduct likelihood determinations and any assumptions related to thelikelihood determination process. If such information is identified during the risk framing step and included as part ofthe organizational risk management strategy, the information need not be repeated in each individual risk assessment.
Organizational assumptions about how to determine likelihood inform Task 2-4.
Impacts
Organizations determine potential adverse impacts in terms of organizational operations (i.e., missions, functions,image, and reputation), organizational assets, individuals, other organizations, and the Nation. Organizations makeexplicit the process used to conduct impact determinations and any assumptions related to the impact determination
process. If such information is identified during the risk framing step and included as part of the organizational risk

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management strategy, the information need not be repeated in each individual risk assessment. Organizations address
impacts at a level of detail that includes, for example, specific mission/business processes or information resources(e.g., information, personnel, equipment, funds, and information technology). Organizations may include informationfrom Business Impact Analyses with regard to providing impact information for risk assessments. Table H-2 provides
representative examples of types of impacts (i.e., harm) that can be considered by organizations. Organizational
assumptions about how to determine impacts and at what level of detail, inform Task 2-5.
Risk Tolerance and Uncertainty
Organizations determine the levels and types of risk that are acceptable. Risk tolerance is determined as part of theorganizational risk management strategy to ensure consistency across the organization. Organizations also provide
guidance on how to identify reasons for uncertainty when risk factors are assessed, since uncertainty in one or morefactors will propagate to the resulting evaluation of level of risk, and how to compensate for incomplete, imperfect, orassumption-dependent estimates. Consideration of uncertainty is especially important when organizations consider
advanced persistent threats (APT) since assessments of the likelihood of threat event occurrence can have a great
degree of uncertainty. To compensate, organizations can take a variety of approaches to determine likelihood, ranging
from assuming the worst-case likelihood (certain to happen sometime in the foreseeable future) to assuming that if an
event has not been observed, it is unlikely to happen. Organizations also determine what levels of risk (combination of
likelihood and impact) indicate that no further analysis of any risk factors is needed.
Analytic Approach
Risk assessments include both assessment approaches (i.e., quantitative, qualitative, semi-quantitative) and analysis
approaches (i.e., threat-oriented, asset/impact-oriented, vulnerability-oriented). Together, the assessment and analysis
approaches form the analytic approach for the risk assessment. Organizations determine the level of detail and in what
form, threats are analyzed including the level of granularity to describe threat events or threat scenarios. Different
analysis approaches can lead to different levels of detail in characterizing adverse events for which likelihoods are
determined. For example, an adverse event could be characterized in several ways (with increasing levels of detail): (i)a threat event (for which the likelihood is determined by taking the maximum overall threat sources); (ii) a pairing of athreat event and a threat source; or (iii) a detailed threat scenario/attack tree. In general, organizations can be expected
to require more detail for highly critical missions/business functions, common infrastructures, or shared services on
which multiple missions or business functions depend (as common points of failure), and information systems withhigh criticality or sensitivity. Mission/business owners may amplify this guidance for risk hot spots (information
systems, services, or critical infrastructure components of particular concern) in mission/business segments.
IDENTIFY INFORMATION SOURCESTASK 1-4: Identify the sources of descriptive, threat, vulnerability, and impact information to be used in therisk assessment.
Supplemental Guidance: Descriptive information enables organizations to be able to determine the relevance of threat
and vulnerability information. At Tier 1, descriptive information can include, for example, the type of risk management
and information security governance structures in place within organizations and how the organization identifies andprioritizes critical missions/business functions. At Tier 2, descriptive information can include, for example, information
about: (i) organizational mission/business processes, functional management processes, and information flows; (ii)enterprise architecture, information security architecture, and the technical/process flow architectures of the systems,common infrastructures, and shared services that fall within the scope of the risk assessment; and (iii) the external
environments in which organizations operate including, for example, the relationships and dependencies with external
providers. Such information is typically found in architectural documentation (particularly documentation of high-level
operational views), business continuity plans, and risk assessment reports for organizational information systems,common infrastructures, and shared services that fall within the scope of the risk assessment. At Tier 3, descriptive
information can include, for example, information about: (i) the design of and technologies used in organizational
information systems; (ii) the environment in which the systems operate; (iii) connectivity to and dependency on otherinformation systems; and (iv) dependencies on common infrastructures or shared services. Such information is found insystem documentation, contingency plans, and risk assessment reports for other information systems, infrastructures,and services.
Sources of information as described in Tables D-1, E-1, F-1, H-1, and I-1 can be either internal or external toorganizations. Internal sources of information that can provide insights into both threats and vulnerabilities can include,for example, risk assessment reports, incident reports, security logs, trouble tickets, and monitoring results. Note thatinternally, information from risk assessment reports at one tier can serve as input to risk assessments at other tiers.
Mission/business owners are encouraged to identify not only common infrastructure and/or support services they
depend on, but also those they might use under specific operational circumstances. External sources of threat
information can include cross-community organizations (e.g., US Computer Emergency Readiness Team [US-CERT],
sector partners (e.g., Defense Industrial Base [DIB] using the DoD-Defense Industrial Base Collaborative Information

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Sharing Environment [DCISE], Information Sharing and Analysis Centers [ISACs] for critical infrastructure sectors),
research and nongovernmental organizations (e.g. Carnegie Mellon University, Software Engineering Institute-CERT),and security service providers). Organizations using external sources, consider the timeliness, specificity, and relevanceof threat information. Similar to sources of threat information, sources of vulnerability information can also be either
internal or external to organizations (see Table F-1). Internal sources can include, for example, vulnerability assessment
reports. External sources of vulnerability information are similar to the sources identified above for threat information.
As described in Table F-1, information about predisposing conditions can be found in a variety of sources including,for example, descriptions of information systems, environments of operation, shared services, common infrastructures,and enterprise architecture. As described in Table H-1, sources of impact information can include, for example,
mission/business impact analyses, information system component inventories, and security categorizations. Security
categorization constitutes a determination of the potential impacts should certain events occur which jeopardize theinformation and information systems needed by the organization to accomplish its assigned missions, protect its assets,
fulfill its legal responsibilities, maintain its day-to-day functions, and protect individuals. Security categories are to be
used in conjunction with vulnerability and threat information in assessing the risk to organizational operations andassets, individuals, other organizations, and the Nation. Security categories constitute an initial summary of impact interms of failures to meet the security objectives of confidentiality, integrity, and availability, and are informed by thetypes of harm presented in Table H-2.
IDENTIFY RISK MODEL AND ANALYTIC APPROACHTASK 1-5: Identify the risk model and analytic approach to be used in the risk assessment.
Supplemental Guidance: Organizations define one or more risk models for use in conducting risk assessments (seeSection 2.3.1) and identify which model is to be used for the risk assessment. To facilitate reciprocity of assessment
results, organization-specific risk models include, or can be translated into, the risk factors (i.e., threat, vulnerability,
impact, likelihood, and predisposing condition) defined in the appendices. Organizations also identify the specificanalytic approach to be used for the risk assessment including the assessment approach (i.e., quantitative, qualitative,
semi-quantitative) and the analysis approach (i.e., threat-oriented, asset/impact-oriented, vulnerability-oriented). For
each assessable risk factor, the appendices include three assessment scales (one qualitative and two semi-quantitative
scales) with correspondingly different representations. Organizations typically define (or select and tailor from theappendices) the assessment scales to be used in their risk assessments, annotating with organizationally-meaningful
examples for specific values and defining break points between bins for semi-quantitative approaches. In addition,
mission/business owners can provide further annotations with mission/business-specific examples. Organizations canidentify different assessment scales to be used in different circumstances. For example, for low-impact information
systems, organizations could use qualitative values, while for moderate- and high-impact systems, the most granularsemi-quantitative values (0-100) could be used. As discussed in Special Publication 800-39, Task 1-1, Risk
Assumptions, organizations vary in the relative weights applied to risk factors. Therefore, this guideline does not
specify algorithms for combining semi-quantitative values. Organization-specific risk models include algorithms (e.g.,
formulas, tables, rules) for combining risk factors. If an organization-specific risk model is not provided in the risk
management strategy as part of the risk framing step, then part of this task is to specify the algorithms for combining
values. Algorithms for combining risk factors reflect organizational risk tolerance (see the supplemental guidance to
Task 2-4 for examples). Organization-specific risk models are refined as part of preparation for a risk assessment by: (i)identifying the risk model and the rationale for using it (when multiple organization-specific risk models are provided);(ii) providing additional examples for values of risk factors; and (iii) identifying any assessment-specific algorithms(e.g., algorithms specific to the use of an attack graph analysis technique). In the absence of pre-existing organizationspecific risk models or analytic approaches defined in the organizational risk management strategy, the risk model andanalytic approaches to be used in the risk assessment are defined and documented in this task.

Summary of Key Activities – Preparing for Risk Assessments•

Identify the purpose of the risk assessment.

•

Identify the scope of the risk assessment.

•

Identify the assumptions and constraints under which the risk assessment is conducted.

•

Identify sources of threat, vulnerability, and impact information to be used in the risk
assessment (see Tables D-1, E-1, F-1, H-1, and I-1 as tailored by the organization).

•

Define or refine the risk model, assessment approach, and analysis approach to be used in
the risk assessment.

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3.2 CONDUCTING THE RISK ASSESSMENT
The second step in the risk assessment process is to conduct the assessment. The objective of thisstep is to produce a list of information security risks that can be prioritized by risk level and used
to inform risk response decisions. To accomplish this objective, organizations analyze threats andvulnerabilities, impacts and likelihood, and the uncertainty associated with the risk assessment
process. This step also includes the gathering of essential information as a part of each task and isconducted in accordance with the assessment context established in the Prepare step of the risk
assessment process. The expectation for risk assessments is to adequately cover the entire threat
space in accordance with the specific definitions, guidance, and direction established during the
Prepare step. However, in practice, adequate coverage within available resources may dictate
generalizing threat sources, threat events, and vulnerabilities to ensure full coverage and assessing
specific, detailed sources, events, and vulnerabilities only as necessary to accomplish risk
assessment objectives. Conducting risk assessments includes the following specific tasks:•

Identify threat sources that are relevant to organizations;•

Identify threat events that could be produced by those sources;•

Identify vulnerabilities within organizations that could be exploited by threat sources throughspecific threat events and the predisposing conditions that could affect successful
exploitation;•

Determine the likelihood that the identified threat sources would initiate specific threat eventsand the likelihood that the threat events would be successful;•

Determine the adverse impacts to organizational operations and assets, individuals, otherorganizations, and the Nation resulting from the exploitation of vulnerabilities by threatsources (through specific threat events); and•Determine information security risks as a combination of likelihood of threat exploitation ofvulnerabilities and the impact of such exploitation, including any uncertainties associatedwith the risk determinations.

The specific tasks are presented in a sequential manner for clarity. However, in practice, someiteration among the tasks is both necessary and expected. 45 Depending on the purpose of the risk
assessment, organizations may find reordering the tasks advantageous. 46 Whatever adjustments
organizations make to the tasks described below, risk assessments should meet the stated purpose,scope, assumptions, and constraints established by the organizations initiating the assessments.
To assist organizations in executing the individual tasks in the risk assessment process, a set of
templates is provided in Appendices D through I. These appendices provide useful informationfor organizations in assessing risk and can also be used to record assessment results produced
during essential calculations and analyses. The templates are exemplary and can be tailored byorganizations in accordance with specific organizational mission/business requirements. The useof the templates is not required in order to conduct risk assessments.
45
For example, as vulnerabilities are identified, additional threat events might be identified by asking how the newly
identified vulnerabilities could be exploited. If organizations identify vulnerabilities first and then define threat events,
there may be some events that do not map cleanly to vulnerabilities but do map to predisposing conditions.
46
For example, the risk assessment could start with an identification of mission/business impacts at Tiers 1 and 2 using
common techniques such as Mission Impact Analyses, Business Impact Analyses, Mission/Business Thread Analyses,
or Business Continuity Analyses. The results of such analyses could enable risk assessors to focus attention on, andperform more detailed analysis of, potential threats to critical information systems, databases, communications links, orother assets.

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Guide for Conducting Risk Assessments________________________________________________________________________________________________STEP 2: CONDUCT THE ASSESSMENTIDENTIFY THREAT SOURCESTASK 2-1: Identify and characterize threat sources of concern, including capability, intent, and targetingcharacteristics for adversarial threats and range of effects for non-adversarial threats.
Supplemental Guidance: Organizations identify threat sources of concern and determine the characteristics associatedwith those threat sources. For adversarial threat sources, assess the capabilities, intentions, and targeting associatedwith the threat sources. For non-adversarial threat sources, assess the potential range of effects from the threat sources.
The risk management strategy and the results of the Prepare step provide organizational direction and guidance for
conducting threat source identification and characterization including, for example: (i) sources for obtaining threat
information; (ii) threat sources to consider (by type/name); (iii) threat taxonomy to be used; and (iv) the process for
identifying which threat sources are of concern for the risk assessment. As identified in Task 1-3, organizations makeexplicit any assumptions concerning threat sources including decisions regarding the identification of threat sources
when specific and credible threat information is unavailable. Organizations can also view adversarial threat sourcesfrom a broad-based perspective, considering the time such threat sources may have to exploit identified organizational
vulnerabilities, the scale of the attack, and the potential use of multiple attack vectors. The identification andcharacterization of Advanced Persistent Threats (APTs) can involve considerable uncertainty. Organizations annotate
such threat sources with appropriate rationale and references (and providing classifications as necessary).
Appendix D provides a set of exemplary tables for use in identifying threat sources:• Table D-1 provides a set of exemplary inputs to the threat source identification task;• Table D-2 provides an exemplary taxonomy that can be used to identify and characterize threat sources;• Tables D-3, D-4, and D-5 provide exemplary assessment scales to assess the risk factors (i.e., characteristics) ofadversarial threat sources with regard to capability, intent, and targeting;• Table D-6 provides an exemplary assessment scale for assessing the ranges of effects from threat events initiated by
non-adversarial threat sources; and• Tables D-7 and D-8 provide templates for summarizing and documenting the results of threat source identificationand characterization.
If a particular type of threat source is outside the scope of the risk assessment or not relevant to the organization, theinformation in Tables D-7 and D-8 can be truncated accordingly. The information produced in Task 2-1 provides threatsource inputs to the risk tables in Appendix I.

Summary of Key Activities – Task 2-1•

Identify threat source inputs (see Table D-1, as tailored by the organization).

•

Identify threat sources (see Table D-2, as tailored by the organization).

•

Determine if threat sources are relevant to the organization and in scope (see Table D-1, as
tailored by the organization).

•

Create or update the assessment of threat sources (see Table D-7 for adversarial threatsources and Table D-8 for non-adversarial threat sources, as tailored by the organization).
•

For relevant adversarial threat sources:-•-

Assess adversary intent (see Table D-4, as tailored by the organization).

-

Assess adversary targeting (see Table D-5, as tailored by the organization).

For relevant non-adversarial threat sources:-

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Assess adversary capability (see Table D-3, as tailored by the organization).

Assess the range of effects from threat sources (see Table D-6, as tailored by theorganization).

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Guide for Conducting Risk Assessments________________________________________________________________________________________________IDENTIFY THREAT EVENTSTASK 2-2: Identify potential threat events, relevance of the events, and the threat sources that could initiate

the events.
Supplemental Guidance: Threat events are characterized by the threat sources that could initiate the events, and foradversarial events, the TTPs used to carry out attacks. Organizations define these threat events with sufficient detail toaccomplish the purpose of the risk assessment. At Tier 1, threat events that could affect the organizational level are ofparticular interest. At Tier 2, threat events that cross or span information system boundaries, exploit functional
dependencies or connectivity among systems, or affect mission/business owners, are of particular interest. At Tier 3,
threat events that can be described in terms of specific information systems, technologies, or environments of operation
are of particular interest. Multiple threat sources can initiate a single threat event. Conversely, a single threat source canpotentially initiate any of multiple threat events. Therefore, there can be a many-to-many relationship among threat
events and threat sources that can potentially increase the complexity of the risk assessment. To enable effective use
and communication of risk assessment results, organizations tailor the general descriptions of threat events in Tables E2 and E-3 to identify how each event could potentially harm organizational operations (including mission, functions,image, or reputation) and assets, individuals, other organizations, or the Nation. For each threat event identified,organizations determine the relevance of the event. Table E-4 provides a range of values for relevance of threat events.
The values selected by organizations have a direct linkage to organizational risk tolerance. The more risk averse, thegreater the range of values considered. Organizations accepting greater risk or having a greater risk tolerance are more
likely to require substantive evidence before giving serious consideration to threat events. If a threat event is deemed tobe irrelevant, no further consideration is given. For relevant threat events, organizations identify all potential threatsources that could initiate the events. For use in Task 2-4, organizations can identify each pairing of threat source andthreat event separately since the likelihood of threat initiation and success could be different for each pairing.
Alternatively, organizations can identify the set of all possible threat sources that could potentially initiate a threat
event.
Appendix E provides a set of exemplary tables for use in identifying threat events:• Table E-1 provides a set of exemplary inputs to the threat event identification task;• Table E-2 provides representative examples of adversarial threat events expressed as TTPs;• Table E-3 provides representative examples of non-adversarial threat events;• Table E-4 provides exemplary values for the relevance of threat events to organizations; and• Table E-5 provides a template for summarizing and documenting the results of threat event identification.
The information produced in Task 2-2 provides threat event inputs to the risk tables in Appendix I.

Summary of Key Activities – Task 2-2•

Identify threat event inputs (see Table E-1, as tailored by the organization).

•

Identify threat events (see Table E-2 for adversarial threat events and Table E-3 for nonadversarial threat events, as tailored by the organization); create or update Table E-5.

•

Identify threat sources that could initiate the threat events (see Table D-7 and Table D-8, as
tailored by the organization); update Table E-5.

•

Assess the relevance of threat events to the organization (see Table E-4, as tailored by theorganization); update Table E-5.

•

Update Columns 1-6 in Table I-5 for adversarial risk (see Table E-5 and Table D-7); or update
Columns 1-4 in Table I-7 for non-adversarial risk (see Table E-5 and Table D-8).

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Guide for Conducting Risk Assessments________________________________________________________________________________________________IDENTIFY VULNERABILITIES AND PREDISPOSING CONDITIONSTASK 2-3: Identify vulnerabilities and predisposing conditions that affect the likelihood that threat events ofconcern result in adverse impacts.
Supplemental Guidance: The primary purpose of vulnerability assessments is to understand the nature and degree towhich organizations, mission/business processes, and information systems are vulnerable to threat sources identified in
Task 2-1 and the threat events identified in Task 2-2 that can be initiated by those threat sources. Vulnerabilities at Tier
1 can be pervasive across organizations and can have wide-ranging adverse impacts if exploited by threat events. For
example, organizational failure to consider supply chain activities can result in organizations acquiring subverted
components that adversaries could exploit to disrupt organizational missions/business functions or to obtain sensitive
organizational information. Vulnerabilities at Tier 2 can be described in terms of organizational mission/businessprocesses, enterprise architecture, the use of multiple information systems, or common infrastructures/shared services.
At Tier 2, vulnerabilities typically cross or span information system boundaries. Vulnerabilities at Tier 3 can be
described in terms of the information technologies employed within organizational information systems, theenvironments in which those systems operate, and/or the lack of or weaknesses in system-specific security controls.
There is potentially a many-to-many relationship between threat events and vulnerabilities. Multiple threat events can
exploit a single vulnerability, and conversely, multiple vulnerabilities can be exploited by a single threat event. The
severity of a vulnerability is an assessment of the relative importance of mitigating such a vulnerability. Initially, theextent to which mitigation is unplanned can serve as a surrogate for vulnerability severity. Once the risks associatedwith a particular vulnerability have been assessed, the impact severity and exposure of the vulnerability given the
security controls implemented and other vulnerabilities can be taken into consideration in assessing vulnerability
severity. Assessments of vulnerability severity support risk response. Vulnerabilities can be identified at varying
degrees of granularity and specificity. The level of detail provided in any particular vulnerability assessment is
consistent with the purpose of the risk assessment and the type of inputs needed to support follow-on likelihood andimpact determinations.
Due to the ever-increasing size and complexity of organizations, mission/business processes, and the information
systems supporting those processes, the number of vulnerabilities tends to be large and can increase the overall
complexity of the analysis. Therefore, organizations have the option of using the vulnerability identification task tounderstand the general nature of the vulnerabilities (including scope, number, and type) relevant to the assessment (seeTask 1-3) and performing a cataloging of specific vulnerabilities as necessary to do so. Organizations determine which
vulnerabilities are relevant to which threat events in order to reduce the space of potential risks to be assessed. In
addition to identifying vulnerabilities, organizations also identify any predisposing conditions which may affectsusceptibility to certain vulnerabilities. Predisposing conditions that exist within organizations (including
mission/business processes, information systems, and environments of operation) can contribute to (i.e., increase or
decrease) the likelihood that one or more threat events, once initiated by threat sources, result in adverse impacts toorganizational operations, organizational assets, individuals, other organizations, or the Nation. Organizations
determine which predisposing conditions are relevant to which threat events in order to reduce the space of potential
risks to be assessed. Organizations assess the pervasiveness of predisposing conditions to support determination of thetier(s) at which risk response could be most effective.
Appendix F provides a set of exemplary tables for use in identifying vulnerabilities and predisposing conditions:• Table F-1 provides a set of exemplary inputs to the vulnerability and predisposing condition identification task;• Table F-2 provides an exemplary assessment scale for assessing the severity of identified vulnerabilities;• Table F-3 provides a template for summarizing/documenting the results of vulnerability identification;• Table F-4 provides an exemplary taxonomy that can be used to identify and characterize predisposing conditions;• Table F-5 provides an exemplary assessment scale for assessing the pervasiveness of predisposing conditions; and• Table F-6 provides a template for summarizing/documenting the results of identifying predisposing conditions.
The information produced in Task 2-3 provides vulnerability and predisposing condition inputs to the risk tables inAppendix I.

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Summary of Key Activities – Task 2-3•

Identify vulnerability and predisposing condition inputs (see Table F-1, as tailored by theorganization).

•

Identify vulnerabilities using organization-defined information sources; create or update
Table F-3.

•

Assess the severity of identified vulnerabilities (see Table F-2, as tailored by theorganization); update Table F-3.

•

Identify predisposing conditions (see Table F-4, as tailored by the organization); create or
update Table F-6.

•

Assess the pervasiveness of predisposing conditions (see Table F-5, as tailored by theorganization); update Table F-6.

•

Update Column 8 in Table I-5 for adversarial risk; or update Column 6 in Table I-7 for nonadversarial risk (see Table F-3 and Table F-6).

•

Update Column 9 in Table I-5 for adversarial risk; or update Column 7 in Table I-7 for nonadversarial risk (see Table F-2 and Table F-5).

DETERMINE LIKELIHOODTASK 2-4: Determine the likelihood that threat events of concern result in adverse impacts, considering: (i)the characteristics of the threat sources that could initiate the events; (ii) the vulnerabilities/predisposing
conditions identified; and (iii) the organizational susceptibility reflecting the safeguards/countermeasuresplanned or implemented to impede such events.
Supplemental Guidance: Organizations employ a three-step process to determine the overall likelihood of threat events.
First, organizations assess the likelihood that threat events will be initiated (for adversarial threat events) or will occur(for non-adversarial threat events). Second, organizations assess the likelihood that threat events once initiated oroccurring, will result in adverse impacts to organizational operations and assets, individuals, other organizations, or the
Nation. Finally, organizations assess the overall likelihood as a combination of likelihood of initiation/occurrence andlikelihood of resulting in adverse impact.
Organizations assess the likelihood of threat event initiation by taking into consideration the characteristics of the threatsources of concern including capability, intent, and targeting (see Task 2-1 and Appendix D). If threat events require
more capability than adversaries possess (and adversaries are cognizant of this fact), then the adversaries are notexpected to initiate the events. If adversaries do not expect to achieve intended objectives by executing threat events,
then the adversaries are not expected to initiate the events. And finally, if adversaries are not actively targeting specificorganizations or their missions/business functions, adversaries are not expected to initiate threat events. Organizations
use the assessment scale in Table G-2 and provide a rationale for the assessment allowing explicit consideration ofdeterrence and threat shifting. Organizations can assess the likelihood of threat event occurrence (non-adversarial)using Table G-3 and provide a similar rationale for the assessment.
Organizations assess the likelihood that threat events result in adverse impacts by taking into consideration the set of
identified vulnerabilities and predisposing conditions (see Task 2-3 and Appendix F). For threat events initiated byadversaries, organizations consider characteristics of associated threat sources. For non-adversarial threat events,organizations take into account the anticipated severity and duration of the event (as included in the description of theevent). Organizations use the assessment scale in Table G-4 and provide a rationale for the assessment allowing explicit
consideration as stated above. Threat events for which no vulnerabilities or predisposing conditions are identified, havea very low likelihood of resulting in adverse impacts. Such threat events can be highlighted and moved to the end of thetable (or to a separate table), so that they can be tracked for consideration in follow-on risk assessments. However, nofurther consideration during the current assessment is warranted.

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Guide for Conducting Risk Assessments________________________________________________________________________________________________The overall likelihood of a threat event is a combination of: (i) the likelihood that the event will occur (e.g., due tohuman error or natural disaster) or be initiated by an adversary; and (ii) the likelihood that the initiation/occurrence will
result in adverse impacts. Organizations assess the overall likelihood of threat events by using inputs from Tables G-2,
G-3, and G-4. Any specific algorithm or rule for combining the determined likelihood values depends on: (i) generalorganizational attitudes toward risk, including overall risk tolerance and tolerance for uncertainty; (ii) specifictolerances toward uncertainty in different risk factors; and (iii) organizational weighting of risk factors. For example,
organizations could use any of the following rules (or could define a different rule): (i) use the maximum of the two
likelihood values; (ii) use the minimum of the two likelihood values; (iii) consider likelihood of initiation/occurrence
only, assuming that if threat events are initiated or occur, the events will result in adverse impacts; (iv) consider
likelihood of impact only, assuming that if threat events could result in adverse impacts, adversaries will initiate theevents; or (v) take a weighted average of the two likelihood values. Organizations make explicit the rules used.
Appendix G provides a set of exemplary tables for use in determining likelihood of threat events:• Table G-1 provides a set of exemplary inputs to the likelihood determination task;• Table G-2 provides an exemplary assessment scale for assessing the likelihood of initiation for adversarial threat
events;• Table G-3 provides an exemplary assessment scale for assessing the likelihood of non-adversarial threat eventsoccurring;• Table G-4 provides an exemplary assessment scale for assessing the likelihood of threat events having adverse
impacts if the events are initiated (adversarial) or occur (non-adversarial); and• Table G-5 provides an exemplary assessment scale for assessing the overall likelihood of threat events (i.e., a
combination of the likelihood of initiation/occurrence and the likelihood of impact).
The information produced in Task 2-4 provides threat event likelihood inputs to the risk tables in Appendix I.

Summary of Key Activities – Task 2-4•

Identify likelihood determination inputs (see Table G-1, as tailored by the organization).

•

Identify likelihood determination factors using organization-defined information sources(e.g., threat source characteristics, vulnerabilities, predisposing conditions).

•

Assess the likelihood of threat event initiation for adversarial threats and the likelihood of
threat event occurrence for non-adversarial threats (see Table G-2 and Table G-3, as tailoredby the organization).

•

Assess the likelihood of threat events resulting in adverse impacts, given likelihood of
initiation or occurrence (see Table G-4, as tailored by the organization).

•

Assess the overall likelihood of threat event initiation/occurrence and likelihood of threat
events resulting in adverse impacts (see Table G-5, as tailored by the organization).

•

Update Columns 7, 10, and 11 in Table I-5 for adversarial risk (see Table G-2, Table G-4, andTable G-5); or update Columns 5, 8, and 9 in Table I-7 for non-adversarial risk (see Table G-3,
Table G-4, and Table G-5).

DETERMINE IMPACTTASK 2-5: Determine the adverse impacts from threat events of concern considering: (i) the characteristics ofthe threat sources that could initiate the events; (ii) the vulnerabilities/predisposing conditions identified;and (iii) the susceptibility reflecting the safeguards/countermeasures planned or implemented to impede
such events.
Supplemental Guidance: Organizations describe adverse impacts in terms of the potential harm caused to organizational
operations and assets, individuals, other organizations, or the Nation. Where the threat event occurs and whether theeffects of the event are contained or spread, influences the severity of the impact. Assessing impact can involve
identifying assets or potential targets of threat sources, including information resources (e.g., information, data

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repositories, information systems, applications, information technologies, communications links), people, and physicalresources (e.g., buildings, power supplies), which could be affected by threat events. Organizational impacts aredefined and prioritized at Tiers 1 and 2, and communicated to Tier 3 as part of risk framing. At Tier 3, impacts areassociated with information system capabilities (e.g., processing, display, communications, storage, and retrieval) andresources (e.g., databases, services, components) that could be compromised.
Appendix H provides a set of exemplary tables for use in determining adverse impacts:• Table H-1 provides a set of exemplary inputs to the impact determination task;• Table H-2 provides representative examples of adverse impacts to organizations focusing on harm to organizational
operations and assets, individuals, other organizations, and the Nation;• Table H-3 provides an exemplary assessment scale for assessing the impact of threat events; and• Table H-4 provides a template for summarizing/documenting adverse impacts.
The information produced in Task 2-5 provides adverse impact inputs to the risk tables in Appendix I.

Summary of Key Activities – Task 2-5•

Identify impact determination inputs (see Table H-1 as tailored by the organization).

•

Identify impact determination factors using organization-defined information sources.

•

Identify adverse impacts and affected assets (see Table H-2, as tailored by the organization);create or update Table H-4.

•

Assess the maximum impact associated with the affected assets (see Table H-3, as tailoredby the organization); update Table H-4.

•

Update Column 12 in Table I-5 for adversarial risk; or update Column 10 in Table I-7 for nonadversarial risk.

DETERMINE RISKTASK 2-6: Determine the risk to the organization from threat events of concern considering: (i) the impactthat would result from the events; and (ii) the likelihood of the events occurring.
Supplemental Guidance: Organizations assess the risks from threat events as a combination of likelihood and impact.
The level of risk associated with identified threat events represents a determination of the degree to whichorganizations are threatened by such events. Organizations make explicit the uncertainty in the risk determinations,
including, for example, organizational assumptions and subjective judgments/decisions. Organizations can order the listof threat events of concern by the level of risk determined during the risk assessment—with the greatest attention goingto high-risk events. Organizations can further prioritize risks at the same level or with similar scores (see Appendix J).
Each risk corresponds to a specific threat event with a level of impact if that event occurs. In general, the risk level istypically not higher than the impact level, and likelihood can serve to reduce risk below that impact level. However,when addressing organization-wide risk management issues with a large number of missions/business functions,
mission/business processes, and supporting information systems, impact as an upper bound on risk may not hold. For
example, when multiple risks materialize, even if each risk is at the moderate level, the set of those moderate-level risks
could aggregate to a higher level of risk for organizations. To address situations where harm occurs multiple times,
organizations can define a threat event as multiple occurrences of harm and an impact level associated with the
cumulative degree of harm. During the execution of Tasks 2-1 through 2-5, organizations capture key information
related to uncertainties in risk assessments. These uncertainties arise from sources such as missing information,subjective determinations, and assumptions made. The effectiveness of risk assessment results is in part determined by
the ability of decision makers to be able to determine the continued applicability of assumptions made as part of theassessment. Information related to uncertainty is compiled and presented in a manner that readily supports informed
risk management decisions.
Appendix I provides a set of exemplary tables for use in determining risk:• Table I-1 provides a set of exemplary inputs to the risk and uncertainty determination task;• Tables I-2 and I-3 provide exemplary assessment scales for assessing levels of risk;

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for adversarial and non-adversarial threat events, respectively.
The information produced in Task 2-6 provides risk inputs to the risk tables in Appendix I.

Summary of Key Activities – Task 2-6•

Identify risk and uncertainty determination inputs (see Table I-1, as tailored by theorganization).

•

Determine risk (see Table I-2 and Table I-3, as tailored by the organization); update Column
13 in Table I-5 for adversarial risk and Column 11 in Table I-7 for non-adversarial risk.

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3.3 COMMUNICATING AND SHARING RISK ASSESSMENT INFORMATION
The third step in the risk assessment process is to communicate the assessment results and sharerisk-related information.47 The objective of this step is to ensure that decision makers across theorganization have the appropriate risk-related information needed to inform and guide risk
decisions. Communicating and sharing information consists of the following specific tasks:•

Communicate the risk assessment results; and•Share information developed in the execution of the risk assessment, to support other risk
management activities.

STEP 3: COMMUNICATE AND SHARE RISK ASSESSMENT RESULTS
COMMUNICATE RISK ASSESSMENT RESULTSTASK 3-1: Communicate risk assessment results to organizational decision makers to support risk responses.
Supplemental Guidance: Organizations can communicate risk assessment results in a variety of ways (e.g., executive
briefings, risk assessment reports, dashboards). Such risk communications can be formal or informal with the content
and format determined by organizations initiating and conducting the assessments. Organizations provide guidance on
specific risk communication and reporting requirements, included as part of preparing for the risk assessment (if notprovided in the risk management strategy as part of the risk framing task). Organizations prioritize risks at the samelevel or with similar scores (see Appendix J). Appendix K provides an example of type of information that may be
included in a risk assessment report or the preferred vehicle for risk communication.
SHARE RISK-RELATED INFORMATIONTASK 3-2: Share risk-related information produced during the risk assessment with appropriateorganizational personnel.
Supplemental Guidance: Organizations share source information and intermediate results and provide guidance on
sharing risk-related information. Information sharing occurs primarily within organizations, via reports and briefings,
and by updating risk-related data repositories with supporting evidence for the risk assessment results. Information
sharing is also supported by documenting the sources of information, analytical processes, and intermediate results(e.g., the completed tables in Appendices D-I), so that risk assessments can be easily maintained. Information sharing
may also occur with other organizations.

Summary of Key Activities – Communicating and Sharing Information•

Determine the appropriate method (e.g., executive briefing, risk assessment report, or
dashboard) to communicate risk assessment results.

•

Communicate risk assessment results to designated organizational stakeholders.

•Share the risk assessment results and supporting evidence in accordance with organizational
policies and guidance.

47

The risk assessment process entails ongoing communications and information sharing between those personnel
performing assessment activities, subject matter experts, and key organizational stakeholders (e.g., mission/businessowners, risk executive [function], chief information security officers, information system owners/program managers).
This communication and information sharing ensures that: (i) the inputs to risk assessments are as accurate as possible;(ii) intermediate results can be used (e.g., to support risk assessments at other tiers); and (iii) results are meaningful anduseful inputs to risk response.

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3.4 MAINTAINING THE RISK ASSESSMENT
The fourth step in the risk assessment process is to maintain the assessment. The objective of thisstep is to keep current, the specific knowledge of the risk organizations incur. The results of risk
assessments inform risk management decisions and guide risk responses. To support the ongoing
review of risk management decisions (e.g., acquisition decisions, authorization decisions for
information systems and common controls, connection decisions), organizations maintain risk
assessments to incorporate any changes detected through risk monitoring. 48 Risk monitoring
provides organizations with the means to, on an ongoing basis: (i) determine the effectiveness ofrisk responses; (ii) identify risk-impacting changes to organizational information systems and theenvironments in which those systems operate; 49 and (iii) verify compliance. 50 Maintaining risk
assessments includes the following specific tasks:•

Monitor risk factors identified in risk assessments on an ongoing basis and understanding
subsequent changes to those factors; and•Update the components of risk assessments reflecting the monitoring activities carried out byorganizations.

STEP 4: MAINTAIN THE ASSESSMENTMONITOR RISK FACTORSTASK 4-1: Conduct ongoing monitoring of the risk factors that contribute to changes in risk to organizational

operations and assets, individuals, other organizations, or the Nation.
Supplemental Guidance: Organizations monitor risk factors of importance on an ongoing basis to ensure that the
information needed to make credible, risk-based decisions continues to be available over time. Monitoring risk factors(e.g., threat sources and threat events, vulnerabilities and predisposing conditions, capabilities and intent of adversaries,
targeting of organizational operations, assets, or individuals) can provide critical information on changing conditions
that could potentially affect the ability of organizations to conduct core missions and business functions. Information
derived from the ongoing monitoring of risk factors can be used to refresh risk assessments at whatever frequency
deemed appropriate. Organizations can also attempt to capture changes in the effectiveness of risk response measuresin order to maintain the currency of risk assessments. The objective is to maintain an ongoing situational awareness ofthe organizational governance structures and activities, mission/business processes, information systems, andenvironments of operation, and thereby all of the risk factors that may affect the risk being incurred by organizations.
Therefore, in applying the risk assessment context or risk frame (i.e., scope, purpose, assumptions, constraints, risk
tolerances, priorities, and trade-offs), organizations consider the part risk factors play in the risk response plan
executed. For example, it is expected to be quite common for the security posture of information systems (that is, therisk factors measured within those systems) to reflect only a part of the organizational risk response, with response
actions at the organization level or mission/business process level providing a significant portion of that response. In
48

Risk monitoring, the fourth step in the risk management process, is described in NIST Special Publication 800-39.
The step in the risk assessment process to maintain the assessment results over time overlaps to some degree with therisk monitoring step in the risk management process and the continuous monitoring step in the RMF. This overlap
reinforces the important concept that many of the activities in the risk management process are complementary andmutually reinforcing. For example, the continuous monitoring step in the RMF can be used to monitor the ongoing
effectiveness of deployed security controls with the results used to inform and guide a more extensive organizationalrisk monitoring process. At the organization level, risk monitoring may include monitoring key risk factors that arenecessary to conduct subsequent risk assessments. Organizations use the risk management strategy to convey key
requirements for maintaining risk assessments including, for example, risk factors to monitor and the frequency of suchmonitoring.
49
NIST Special Publication 800-137 provides guidance on the ongoing monitoring of organizational information
systems and environments of operation.
50

Compliance verification ensures that organizations have implemented required risk response measures and that
information security requirements derived from and traceable to organizational missions/business functions, federal
legislation, directives, regulations, policies, and standards/guidelines are satisfied.

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such situations, monitoring only the security posture of information systems would likely not provide sufficient
information to determine the overall risk being incurred by organizations. Highly capable, well-resourced, and purposedriven threat sources can be expected to defeat commonly available protection mechanisms (e.g., by bypassing or
tampering with such mechanisms). Thus, process-level risk response measures such as reengineering mission/businessprocesses, wise use of information technology, or the use of alternate execution processes, in the event of compromised
information systems, can be major elements of organizational risk response plans.
UPDATE RISK ASSESSMENTTASK 4-2: Update existing risk assessment using the results from ongoing monitoring of risk factors.
Supplemental Guidance: Organizations determine the frequency and the circumstances under which risk assessments
are updated. Such determinations can include, for example, the current level of risk to and/or the importance of, coreorganizational missions/business functions. If significant changes (as defined by organizational policies, direction, or
guidance) have occurred since the risk assessment was conducted, organizations can revisit the purpose, scope,
assumptions, and constraints of the assessment to determine whether all tasks in the risk assessment process need to berepeated. Otherwise, the updates constitute subsequent risk assessments, identifying and assessing only how selectedrisk factors have changed, for example: (i) the identification of new threat events, vulnerabilities, predisposing
conditions, undesirable consequences and/or affected assets; and (ii) the assessments of threat source characteristics(e.g., capability, intent, targeting, range of effects), likelihoods, and impacts. Organizations communicate the results ofsubsequent risk assessments to entities across all risk management tiers to ensure that responsible organizational
officials have access to critical information needed to make ongoing risk-based decisions.

Summary of Key Activities – Maintaining Risk Assessments•

Identify key risk factors that have been identified for ongoing monitoring.

•

Identify the frequency of risk factor monitoring activities and the circumstances under which
the risk assessment needs to be updated.

•

Reconfirm the purpose, scope, and assumptions of the risk assessment.

•

Conduct the appropriate risk assessment tasks, as needed.

•

Communicate the subsequent risk assessment results to specified organizational personnel.

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APPENDIX AREFERENCES
LAWS, POLICIES, DIRECTIVES, INSTRUCTIONS, STANDARDS, AND GUIDELINESLEGISLATION

1.

E-Government Act [includes FISMA] (P.L. 107-347), December 2002.

2.

Federal Information Security Management Act (P.L. 107-347, Title III), December 2002.
POLICIES, DIRECTIVES, INSTRUCTIONS

1.

Office of Management and Budget, Circular A-130, Appendix III, Transmittal
Memorandum #4, Management of Federal Information Resources, November 2000.

2.

Committee on National Security Systems Instruction (CNSSI) No. 4009, National
Information Assurance (IA) Glossary, April 2010.

3.

Committee on National Security Systems Instruction (CNSSI) No. 1253, Security
Categorization and Control Selection for National Security Systems, March 2012.

4.

Department of Homeland Security Federal Continuity Directive 2 (FCD 2), Federal
Executive Branch Mission Essential Function and Primary Mission Essential Function
Identification and Submission Process, February 2008.
STANDARDS

1.

National Institute of Standards and Technology Federal Information Processing
Standards Publication 199, Standards for Security Categorization of Federal Information
and Information Systems, February 2004.

2.

National Institute of Standards and Technology Federal Information Processing
Standards Publication 200, Minimum Security Requirements for Federal Information andInformation Systems, March 2006.

3.

ISO/IEC 31000:2009, Risk management – Principles and guidelines.

4.

ISO/IEC 30101:2009, Risk management – Risk assessment techniques.

5.

ISO/IEC Guide 73, Risk management – Vocabulary.

6.

ISO/IEC 27005:2011, Information technology – Security techniques – Information
security risk management.
GUIDELINES

1.

National Institute of Standards and Technology Special Publication 800-18, Revision 1,
Guide for Developing Security Plans for Federal Information Systems, February 2006.

2.

National Institute of Standards and Technology Special Publication 800-34, Revision 1,
Contingency Planning Guide for Federal Information Systems, May 2010.

3.

National Institute of Standards and Technology Special Publication 800-37, Revision 1,
Guide for Applying the Risk Management Framework to Federal Information Systems: A
Security Life Cycle Approach, February 2010.

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4.

National Institute of Standards and Technology Special Publication 800-39, Managing
Information Security Risk: Organization, Mission, and Information System View, March
2011.

5.

National Institute of Standards and Technology Special Publication 800-53, Revision 3,
Recommended Security Controls for Federal Information Systems and Organizations,
August 2009.

6.

National Institute of Standards and Technology Special Publication 800-53A, Revision 1,
Guide for Assessing the Security Controls in Federal Information Systems andOrganizations: Building Effective Security Assessment Plans, June 2010.

7.

National Institute of Standards and Technology Special Publication 800-59, Guideline for
Identifying an Information System as a National Security System, August 2003.

8.

National Institute of Standards and Technology Special Publication 800-60, Revision 1,
Guide for Mapping Types of Information and Information Systems to Security Categories,
August 2008.

9.

National Institute of Standards and Technology Special Publication 800-64, Revision 2,
Security Considerations in the System Development Life Cycle, October 2008.

10.

National Institute of Standards and Technology Special Publication 800-65, Integrating
IT Security into the Capital Planning and Investment Control Process, January 2005.

11.

National Institute of Standards and Technology Special Publication 800-70, Revision 2,
National Checklist Program for IT Products--Guidelines for Checklist Users andDevelopers, February 2011.

12.

National Institute of Standards and Technology Special Publication 800-117, Version 1.0,
Guide to Adopting and Using the Security Content Automation Protocol (SCAP), July
2010.

13.

National Institute of Standards and Technology Special Publication 800-126, The
Technical Specification for the Security Content Automation Protocol (SCAP): SCAP
Version 1.0, November 2009.

14.

National Institute of Standards and Technology Special Publication 800-137, Information
Security Continuous Monitoring for Federal Information Systems and Organizations,
September 2011.

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APPENDIX BGLOSSARYCOMMON TERMS AND DEFINITIONST

his appendix provides definitions for security terminology used within Special Publication
800-30. The terms in the glossary are consistent with the terms used in the suite of
FISMA-related security standards and guidelines developed by NIST. Unless otherwise
stated, all terms used in this publication are also consistent with the definitions contained in the
CNSSI No. 4009, National Information Assurance (IA) Glossary.
Adequate Security[OMB Circular A-130, Appendix III]

Advanced Persistent Threat[NIST SP 800-39]

Adversary

Security commensurate with the risk and magnitude ofharm resulting from the loss, misuse, or unauthorizedaccess to or modification of information.
An adversary with sophisticated levels of expertise andsignificant resources, allowing it through the use ofmultiple different attack vectors (e.g., cyber, physical,
and deception), to generate opportunities to achieve its
objectives which are typically to establish and extend its
presence within the information technology infrastructureof organizations for purposes of continually exfiltrating
information and/or to undermine or impede criticalaspects of a mission, program, or organization, or place
itself in a position to do so in the future; moreover, theadvanced persistent threat pursues its objectives
repeatedly over an extended period of time, adapting to a
defender’s efforts to resist it, and with determination tomaintain the level of interaction needed to execute its
objectives.

[DHS Risk Lexicon]

Individual, group, organization, or government that
conducts or has the intent to conduct detrimental
activities.

AgencySee Executive Agency.

Analysis Approach

The approach used to define the orientation or starting
point of the risk assessment, the level of detail in theassessment, and how risks due to similar threat scenarios
are treated.

Assessment

See Security Control Assessment or Risk Assessment.

Assessment Approach

The approach used to assess risk and its contributing risk
factors, including quantitatively, qualitatively, or semiquantitatively.

Assessor

See Security Control Assessor or Risk Assessor.

AttackAny kind of malicious activity that attempts to collect,disrupt, deny, degrade, or destroy information system
resources or the information itself.

[CNSSI No. 4009]

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Authentication[FIPS 200]

Authenticity[CNSSI No. 4009]

Authorization(to operate)[CNSSI No. 4009]

Authorization Boundary[CNSSI No. 4009]

Authorizing Official[CNSSI No. 4009]

Availability[44 U.S.C., Sec. 3542]

Chief Information Officer[PL 104-106, Sec. 5125(b)]Verifying the identity of a user, process, or device, often
as a prerequisite to allowing access to resources in an
information system.
The property of being genuine and being able to beverified and trusted; confidence in the validity of atransmission, a message, or message originator. See
Authentication.
The official management decision given by a seniororganizational official to authorize operation of an
information system and to explicitly accept the risk toorganizational operations (including mission, functions,image, or reputation), organizational assets, individuals,
other organizations, and the Nation based on theimplementation of an agreed-upon set of security
controls.
All components of an information system to beauthorized for operation by an authorizing official andexcludes separately authorized systems, to which theinformation system is connected.
Senior (federal) official or executive with the authority toformally assume responsibility for operating an
information system at an acceptable level of risk toorganizational operations (including mission, functions,image, or reputation), organizational assets, individuals,
other organizations, and the Nation.
Ensuring timely and reliable access to and use of
information.
Agency official responsible for:(i) Providing advice and other assistance to the head ofthe executive agency and other senior management
personnel of the agency to ensure that information
technology is acquired and information resources aremanaged in a manner that is consistent with laws,
Executive Orders, directives, policies, regulations, andpriorities established by the head of the agency;(ii) Developing, maintaining, and facilitating theimplementation of a sound and integrated information
technology architecture for the agency; and(iii) Promoting the effective and efficient design andoperation of all major information resources management
processes for the agency, including improvements towork processes of the agency.

Chief Information Security Officer

See Senior Agency Information Security Officer.

Common Control

A security control that is inherited by one or moreorganizational information systems. See Security Control
Inheritance.

[NIST SP 800-37]

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Common Control Provider[CNSSI No. 4009]

Compensating Security Control[CNSSI No. 4009]

Confidentiality[44 U.S.C., Sec. 3542]

Course of Action[NIST SP 800-39]

An organizational official responsible for thedevelopment, implementation, assessment, andmonitoring of common controls (i.e., security controls
inherited by information systems).
A management, operational, and/or technical control (i.e.,
safeguard or countermeasure) employed by anorganization in lieu of a recommended security control in
the low, moderate, or high baselines that provides
equivalent or comparable protection for an information
system.
Preserving authorized restrictions on information accessand disclosure, including means for protecting personalprivacy and proprietary information.
A time-phased or situation-dependent combination of risk
response measures. See Risk Response.

Critical Infrastructure

System and assets, whether physical or virtual, so vital to
the United States that the incapacity or destruction ofsuch systems and assets would have a debilitating impact
on security, national economic security, national publichealth or safety, or any combination of those matters.

Critical Infrastructure Sectors

Information technology; telecommunications; chemical;
transportation systems, including mass transit, aviation,
maritime, ground/surface, and rail and pipeline systems;
emergency services; and postal and shipping.

[HSPD-7]

Criticality[NIST SP 800-60]

Cyber Attack[CNSSI No. 4009]

Cyber Security[CNSSI No. 4009]

Cyberspace[CNSSI No. 4009]

APPENDIX B

A measure of the degree to which an organization
depends on the information or information system for the
success of a mission or of a business function.
An attack, via cyberspace, targeting an enterprise’s use of
cyberspace for the purpose of disrupting, disabling,
destroying, or maliciously controlling a computing
environment/infrastructure; or destroying the integrity ofthe data or stealing controlled information.
The ability to protect or defend the use of cyberspacefrom cyber attacks.
A global domain within the information environment
consisting of the interdependent network of information
systems infrastructures including the Internet,
telecommunications networks, computer systems, andembedded processors and controllers.

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Defense-in-Breadth[CNSSI No. 4009]

Defense-in-Depth[CNSSI No. 4009]

Enterprise[CNSSI No. 4009]

Enterprise Architecture[CNSSI No. 4009]

A planned, systematic set of multidisciplinary activities
that seek to identify, manage, and reduce risk of
exploitable vulnerabilities at every stage of the system,
network, or subcomponent life cycle (system, network, or
product design and development; manufacturing;packaging; assembly; system integration; distribution;
operations; maintenance; and retirement).
Information security strategy integrating people,
technology, and operations capabilities to establish
variable barriers across multiple layers and missions of
the organization.
An organization with a defined mission/goal and adefined boundary, using information systems to executethat mission, and with responsibility for managing its
own risks and performance. An enterprise may consist of
all or some of the following business aspects: acquisition,
program management, financial management (e.g.,budgets), human resources, security, and information
systems, information and mission management. See
Organization.
The description of an enterprise’s entire set of
information systems: how they are configured, how they
are integrated, how they interface to the external
environment at the enterprise’s boundary, how they areoperated to support the enterprise mission, and how they
contribute to the enterprise’s overall security posture.

Environment of Operation

The physical, technical, and organizational setting inwhich an information system operates, including but notlimited to: missions/business functions; mission/businessprocesses; threat space; vulnerabilities; enterprise andinformation security architectures; personnel; facilities;
supply chain relationships; information technologies;
organizational governance and culture; acquisition andprocurement processes; organizational policies andprocedures; organizational assumptions, constraints, risk
tolerance, and priorities/trade-offs).

Executive Agency

An executive department specified in 5 U.S.C., Sec. 101;a military department specified in 5 U.S.C., Sec. 102; anindependent establishment as defined in 5 U.S.C., Sec.
104(1); and a wholly owned Government corporation
fully subject to the provisions of 31 U.S.C., Chapter 91.

[41 U.S.C., Sec. 403]

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Fault Tree Analysis

A top-down, deductive failure analysis in which an
undesired state of a system (top event) is analyzed using
Boolean logic to combine a series of lower-level events.
An analytical approach whereby an undesired state of asystem is specified and the system is then analyzed in thecontext of its environment of operation to find all realistic
ways in which the undesired event (top event) can occur.

Federal Agency

See Executive Agency.

Federal Information
SystemAn information system used or operated by an executive
agency, by a contractor of an executive agency, or byanother organization on behalf of an executive agency.

[40 U.S.C., Sec. 11331]

Hybrid Security Control[NIST SP 800-53]

Impact Level[CNSSI No. 4009]

Impact Value[CNSSI No. 1253]

Industrial Control System[NIST SP 800-39]

Information[CNSSI No. 4009][FIPS 199]

Information Owner[CNSSI No. 4009]

Information Resources[44 U.S.C., Sec. 3502]

APPENDIX B

A security control that is implemented in an information
system in part as a common control and in part as asystem-specific control. See Common Control andSystem-Specific Security Control.
The magnitude of harm that can be expected to result
from the consequences of unauthorized disclosure of
information, unauthorized modification of information,
unauthorized destruction of information, or loss of
information or information system availability.
The assessed potential impact resulting from acompromise of the confidentiality, integrity, oravailability of an information type, expressed as a valueof low, moderate, or high.
An information system used to control industrial
processes such as manufacturing, product handling,
production, and distribution. Industrial control systems
include supervisory control and data acquisition systems
used to control geographically dispersed assets, as well as
distributed control systems and smaller control systems
using programmable logic controllers to control localized
processes.
Any communication or representation of knowledge suchas facts, data, or opinions in any medium or form,
including textual, numerical, graphic, cartographic,
narrative, or audiovisual.
An instance of an information type.
Official with statutory or operational authority forspecified information and responsibility for establishing
the controls for its generation, classification, collection,
processing, dissemination, and disposal. See Information
Steward.
Information and related resources, such as personnel,
equipment, funds, and information technology.

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Information Security[44 U.S.C., Sec. 3542]

Information Security Architecture[NIST SP 800-39]

Information Security Program Plan[NIST SP 800-53]

The protection of information and information systems
from unauthorized access, use, disclosure, disruption,
modification, or destruction in order to provide
confidentiality, integrity, and availability.
A description of the structure and behavior for an
enterprise’s security processes, information security
systems, personnel and organizational sub-units, showing
their alignment with the enterprise’s mission and strategicplans.
Formal document that provides an overview of the
security requirements for an organization-wide
information security program and describes the program
management controls and common controls in place orplanned for meeting those requirements.

Information Security Risk

The risk to organizational operations (including mission,functions, image, reputation), organizational assets,
individuals, other organizations, and the Nation due to thepotential for unauthorized access, use, disclosure,disruption, modification, or destruction of information
and/or information systems. See Risk.

Information Steward

An agency official with statutory or operational authority
for specified information and responsibility forestablishing the controls for its generation, collection,
processing, dissemination, and disposal.

[CNSSI No. 4009]

Information System[44 U.S.C., Sec. 3502]

A discrete set of information resources organized for thecollection, processing, maintenance, use, sharing,
dissemination, or disposition of information.

Information System Boundary

See Authorization Boundary.

Information System Owner(or Program Manager)

Official responsible for the overall procurement,
development, integration, modification, or operation andmaintenance of an information system.

Information System Resilience

The ability of an information system to continue tooperate while under attack, even if in a degraded ordebilitated state, and to rapidly recover operational
capabilities for essential functions after a successful
attack.

Information System
Security Officer

Individual assigned responsibility by the senior agency
information security officer, authorizing official,management official, or information system owner for
maintaining the appropriate operational security posture
for an information system or program.

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Information System-Related
Security Risk

Risk that arises through the loss of confidentiality,
integrity, or availability of information or information
systems considering impacts to organizational operations
and assets, individuals, other organizations, and the
Nation. A subset of Information Security Risk. See Risk.

Information Technology

Any equipment or interconnected system or subsystem ofequipment that is used in the automatic acquisition,
storage, manipulation, management, movement, control,
display, switching, interchange, transmission, or
reception of data or information by the executive agency.
For purposes of the preceding sentence, equipment isused by an executive agency if the equipment is used by
the executive agency directly or is used by a contractor
under a contract with the executive agency which: (i)requires the use of such equipment; or (ii) requires theuse, to a significant extent, of such equipment in theperformance of a service or the furnishing of a product.
The term information technology includes computers,
ancillary equipment, software, firmware, and similar
procedures, services (including support services), andrelated resources.

[40 U.S.C., Sec. 1401]

Information Type[FIPS 199]

Integrity[44 U.S.C., Sec. 3542]

Likelihood of Occurrence[CNSSI No. 4009, adapted]

Management Controls[FIPS 200]

Mission/Business Segment

APPENDIX B

A specific category of information (e.g., privacy,
medical, proprietary, financial, investigative, contractor
sensitive, security management) defined by anorganization or in some instances, by a specific law,
Executive Order, directive, policy, or regulation.
Guarding against improper information modification or
destruction, and includes ensuring information nonrepudiation and authenticity.
A weighted factor based on a subjective analysis of theprobability that a given threat is capable of exploiting agiven vulnerability or a set of vulnerabilities.
The security controls (i.e., safeguards orcountermeasures) for an information system that focus on
the management of risk and the management of
information system security.
Elements of organizations describing mission areas,
common/shared business services, and organization-wideservices. Mission/business segments can be identified
with one or more information systems which collectively
support a mission/business process.

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National Security System[44 U.S.C., Sec. 3542]

Operational Controls[FIPS 200]

Organization[FIPS 200, Adapted]

Plan of Action andMilestones[OMB Memorandum 02-01]

Any information system (including any
telecommunications system) used or operated by anagency or by a contractor of an agency, or otherorganization on behalf of an agency (i) the function,
operation, or use of which involves intelligence activities;
involves cryptologic activities related to national security;
involves command and control of military forces;
involves equipment that is an integral part of a weapon or
weapons system; or is critical to the direct fulfillment ofmilitary or intelligence missions (excluding a system thatis to be used for routine administrative and businessapplications, for example, payroll, finance, logistics, andpersonnel management applications); or (ii) is protected
at all times by procedures established for information thathave been specifically authorized under criteria
established by an Executive Order or an Act of Congress
to be kept classified in the interest of national defense orforeign policy.
The security controls (i.e., safeguards orcountermeasures) for an information system that areprimarily implemented and executed by people (asopposed to systems).
An entity of any size, complexity, or positioning within
an organizational structure (e.g., a federal agency or, as
appropriate, any of its operational elements). See
Enterprise.
A document that identifies tasks needing to beaccomplished. It details resources required to accomplish
the elements of the plan, any milestones in meeting thetasks, and scheduled completion dates for the milestones.

Predisposing Condition

A condition that exists within an organization, amission/business process, enterprise architecture, orinformation system including its environment ofoperation, which contributes to (i.e., increases ordecreases) the likelihood that one or more threat events,
once initiated, will result in undesirable consequences oradverse impact to organizational operations and assets,
individuals, other organizations, or the Nation.

Qualitative Assessment

Use of a set of methods, principles, or rules for assessing
risk based on nonnumerical categories or levels.

[DHS Risk Lexicon]

Quantitative Assessment[DHS Risk Lexicon]

Repeatability

APPENDIX B

Use of a set of methods, principles, or rules for assessing
risks based on the use of numbers where the meanings
and proportionality of values are maintained inside andoutside the context of the assessment.
The ability to repeat an assessment in the future, in amanner that is consistent with, and hence comparable to,prior assessments.

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Reproducibility

The ability of different experts to produce the same
results from the same data.

Residual Risk

Portion of risk remaining after security measures havebeen applied.

[CNSSI No. 4009]

Risk[CNSSI No. 4009]

Risk Assessment[NIST SP 800-39]

A measure of the extent to which an entity is threatenedby a potential circumstance or event, and typically afunction of: (i) the adverse impacts that would arise if thecircumstance or event occurs; and (ii) the likelihood of
occurrence. See Information System-Related Security
Risk.
The process of identifying, estimating, and prioritizing
risks to organizational operations (including mission,functions, image, reputation), organizational assets,
individuals, other organizations, and the Nation, resulting
from the operation of an information system.
Part of risk management, incorporates threat andvulnerability analyses, and considers mitigations
provided by security controls planned or in place.
Synonymous with risk analysis.

Risk Assessment Methodology

A risk assessment process, together with a risk model,
assessment approach, and analysis approach.

Risk Assessment Report

The report which contains the results of performing a risk
assessment or the formal output from the process ofassessing risk.

Risk Assessor

The individual, group, or organization responsible for
conducting a risk assessment.

Risk Executive (Function)

An individual or group within an organization that helps
to ensure that: (i) security risk-related considerations forindividual information systems, to include theauthorization decisions for those systems, are viewed
from an organization-wide perspective with regard to theoverall strategic goals and objectives of the organizationin carrying out its missions and business functions; and(ii) managing risk from individual information systems is
consistent across the organization, reflects organizationalrisk tolerance, and is considered along with otherorganizational risks affecting mission/business success.

[CNSSI No. 4009]

Risk Factor

APPENDIX B

A characteristic used in a risk model as an input todetermining the level of risk in a risk assessment.

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Risk Management[NIST SP 800-39][CNSSI No. 4009, adapted]

Risk Mitigation[CNSSI No. 4009]

The program and supporting processes to manage
information security risk to organizational operations(including mission, functions, image, reputation),organizational assets, individuals, other organizations,and the Nation, and includes: (i) establishing the context
for risk-related activities; (ii) assessing risk; (iii)
responding to risk once determined; and (iv) monitoringrisk over time.
Prioritizing, evaluating, and implementing theappropriate risk-reducing controls/countermeasures
recommended from the risk management process. A
subset of Risk Response.

Risk Model

A key component of a risk assessment methodology (inaddition to assessment approach and analysis approach)that defines key terms and assessable risk factors.

Risk Monitoring

Maintaining ongoing awareness of an organization’s risk
environment, risk management program, and associatedactivities to support risk decisions.

[NIST SP 800-39]

Risk Response[NIST SP 800-39]

Risk Response Measure

Accepting, avoiding, mitigating, sharing, or transferringrisk to organizational operations (i.e., mission, functions,image, or reputation), organizational assets, individuals,
other organizations, or the Nation. See Course of Action.
A specific action taken to respond to an identified risk.

[NIST SP 800-39]

Root Cause Analysis

A principle-based, systems approach for the identificationof underlying causes associated with a particular set ofrisks.

Security Authorization(to Operate)

See Authorization (to operate).

Security Categorization

The process of determining the security category for
information or an information system. Security
categorization methodologies are described in CNSSI
No.1253 for national security systems and in FIPS 199
for other than national security systems.

Security Control Assessment

The testing and/or evaluation of the management,
operational, and technical security controls to determine
the extent to which the controls are implemented
correctly, operating as intended, and producing thedesired outcome with respect to meeting the security
requirements for an information system or organization.

[NIST SP 800-39][CNSSI No. 4009, Adapted]

Security Control Assessor

APPENDIX B

The individual, group, or organization responsible for
conducting a security control assessment.

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Security Control Baseline[CNSSI No. 4009][CNSSI No. 1253]

Security Control Enhancement[NIST SP 800-39, adapted]

Security Control Inheritance[CNSSI No. 4009]

Security Controls[FIPS 199, CNSSI No. 4009]

The set of minimum security controls defined for a lowimpact, moderate-impact, or high-impact information
system.
A set of information security controls that has been
established through information security strategicplanning activities to address one or more specified
security categorizations; this set of security controls is
intended to be the initial security control set selected for a
specific system once that system’s security categorization
is determined.
Statement of security capability to: (i) build in additional,
but related, functionality to a basic security control;
and/or (ii) increase the strength of a basic control.
A situation in which an information system or application
receives protection from security controls (or portions of
security controls) that are developed, implemented,
assessed, authorized, and monitored by entities other thanthose responsible for the system or application; entities
either internal or external to the organization where thesystem or application resides. See Common Control.
The management, operational, and technical controls(i.e., safeguards or countermeasures) prescribed for an
information system to protect the confidentiality,
integrity, and availability of the system and its
information.

[NIST SP 800-37]

The analysis conducted by an organizational official todetermine the extent to which changes to the information
system have affected the security state of the system.

Security Objective

Confidentiality, integrity, or availability.

Security Impact Analysis[FIPS 199]

Security Plan[NIST SP 800-18]

Security Policy

Formal document that provides an overview of the
security requirements for an information system or an
information security program and describes the security
controls in place or planned for meeting thoserequirements.
See System Security Plan or Information Security
Program Plan.
A set of criteria for the provision of security services.

[CNSSI No. 4009]

Security Posture[CNSSI No. 4009]

APPENDIX B

The security status of an enterprise’s networks,
information, and systems based on information assurance
resources (e.g., people, hardware, software, policies) andcapabilities in place to manage the defense of theenterprise and to react as the situation changes.

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Security Requirements[FIPS 200]

Semi-Quantitative Assessment[Department of Homeland Security(DHS) Risk Lexicon]

Senior Agency
Information Security
Officer[44 U.S.C., Sec. 3544]

Requirements levied on an information system that arederived from applicable laws, Executive Orders,
directives, policies, standards, instructions, regulations,procedures, or organizational mission/business case needs
to ensure the confidentiality, integrity, and availability of
the information being processed, stored, or transmitted.
Use of a set of methods, principles, or rules for assessing
risk based on bins, scales, or representative numbers
whose values and meanings are not maintained in othercontexts.
Official responsible for carrying out the Chief
Information Officer responsibilities under FISMA andserving as the Chief Information Officer’s primary liaison
to the agency’s authorizing officials, information systemowners, and information system security officers.
[Note: Organizations subordinate to federal agencies may use the term
Senior Information Security Officer or Chief Information Security
Officer to denote individuals filling positions with similar
responsibilities to Senior Agency Information Security Officers.]

Senior Information Security
Officer

See Senior Agency Information Security Officer.

Sensitivity

A measure of the importance assigned to information by
its owner, for the purpose of denoting its need forprotection.

[NIST SP 800-60]

Subsystem[NIST SP 800-39]

A major subdivision or component of an information
system consisting of information, information
technology, and personnel that performs one or more
specific functions.

[NIST SP 800-39]

The process of adding security controls or control
enhancements to a security control baseline from NIST
Special Publication 800-53 or CNSSI No. 1253 in orderto adequately meet the organization’s risk management
needs.

SystemSee Information System.

System Security Plan

Formal document that provides an overview of the
security requirements for an information system anddescribes the security controls in place or planned formeeting those requirements.

Supplementation (Security
Controls)[NIST SP 800-18]

System-Specific Security Control[NIST SP 800-37]

APPENDIX B

A security control for an information system that has notbeen designated as a common control or the portion of a
hybrid control that is to be implemented within an
information system.

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Tailoring[NIST SP 800-53, CNSSI No. 4009]

Tailored Security Control Baseline[NIST SP 800-39]

Technical Controls[FIPS 200]

Threat[CNSSI No.4009]

Threat Assessment[CNSSI No. 4009]

The process by which a security control baseline ismodified based on: (i) the application of scoping
guidance; (ii) the specification of compensating security
controls, if needed; and (iii) the specification oforganization-defined parameters in the security controls
via explicit assignment and selection statements.
A set of security controls resulting from the applicationof tailoring guidance to the security control baseline. See
Tailoring.
Security controls (i.e., safeguards or countermeasures) for
an information system that are primarily implemented
and executed by the information system throughmechanisms contained in the hardware, software, or
firmware components of the system.
Any circumstance or event with the potential to adversely
impact organizational operations (including mission,functions, image, or reputation), organizational assets,
individuals, other organizations, or the Nation through an
information system via unauthorized access, destruction,
disclosure, or modification of information, and/or denialof service.
Process of formally evaluating the degree of threat to an
information system or enterprise and describing thenature of the threat.

Threat Event

An event or situation that has the potential for causing
undesirable consequences or impact.

Threat Scenario

A set of discrete threat events, associated with a specificthreat source or multiple threat sources, partially orderedin time. Synonym for Threat Campaign.

Threat Shifting

Response from adversaries to perceived safeguards
and/or countermeasures (i.e., security controls), in which
the adversaries change some characteristic of their intent
to do harm in order to avoid and/or overcome thosesafeguards/countermeasures.

Threat Source

The intent and method targeted at the intentional
exploitation of a vulnerability or a situation and methodthat may accidentally exploit a vulnerability.

[CNSSI No. 4009]

Vulnerability[CNSSI No. 4009]

Vulnerability Assessment[CNSSI No. 4009]

APPENDIX B

Weakness in an information system, system security
procedures, internal controls, or implementation that
could be exploited by a threat source.
Systematic examination of an information system or
product to determine the adequacy of security measures,
identify security deficiencies, provide data from which topredict the effectiveness of proposed security measures,and confirm the adequacy of such measures after
implementation.

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APPENDIX CACRONYMS
COMMON ABBREVIATIONS

APTAdvanced Persistent Threat

BCP

Business Continuity Plan

BIA

Business Impact Analysis

CNSS

Committee on National Security Systems

COOP

Continuity of Operations

DoD

Department of Defense

DHS

Department of Homeland Security

DNI

Director of National Intelligence

EA

Enterprise Architecture

FIPS

Federal Information Processing Standards

FISMA

Federal Information Security Management Act

ICS

Industrial Control System

IEC

International Electrotechnical Commission

ISO

International Organization for Standardization

IT

Information Technology

JTF

Joint Task ForceNIST

National Institute of Standards and Technology

NOFORN

Not Releasable to Foreign Nationals

ODNI

Office of the Director of National Intelligence

OMB

Office of Management and Budget

RAR

Risk Assessment Report

RMF

Risk Management Framework

SCAP

Security Content Automation Protocol

SP

Special Publication

TTP

Tactic Technique Procedure

U.S.C.

United States CodeAPPENDIX CPAGE C-1

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APPENDIX D

THREAT SOURCESTAXONOMY OF THREATS SOURCES CAPABLE OF INITIATING THREAT EVENTST

his appendix provides: (i) a description of potentially useful inputs to the threat source
identification task; (ii) an exemplary taxonomy of threat sources by type, description, andrisk factors (i.e., characteristics) used to assess the likelihood and/or impact of such threatsources initiating threat events; (iii) an exemplary set of tailorable assessment scales for assessing
those risk factors; and (iv) templates for summarizing and documenting the results of the threatsource identification Task 2-1. The taxonomy and assessment scales in this appendix can be usedby organizations as a starting point with appropriate tailoring to adjust for organization-specificconditions. Tables D-7 and D-8, outputs from Task 2-1, provide relevant inputs to the risk tables
in Appendix I.
TABLE D-1: INPUTS – THREAT SOURCE IDENTIFICATION
Provided To

Description
From Tier 1: (Organization level)

Tier 1

Tier 2No

Yes- Sources of threat information deemed to be credible (e.g., open source and/or classified threat
reports, previous risk/threat assessments). (Section 3.1, Task 1-4)
- Threat source information and guidance specific to Tier 1 (e.g., threats related to organizational
governance, core missions/business functions, management/operational policies, procedures, andstructures, external mission/business relationships).
- Taxonomy of threat sources, annotated by the organization, if necessary. (Table D-2)
- Characterization of adversarial and non-adversarial threat sources.
- Assessment scales for assessing adversary capability, intent, and targeting, annotated by theorganization, if necessary. (Table D-3, Table D-4, Table D-5)
- Assessment scale for assessing the range of effects, annotated by the organization, if necessary.
(Table D-6)
- Threat sources identified in previous risk assessments, if appropriate.
From Tier 2: (Mission/business process level)

Tier 3Yes
if notprovided byTier 2

via
RAR

Yes

via
peer
sharing

Yes- Threat source information and guidance specific to Tier 2 (e.g., threats related to mission/businessprocesses, EA segments, common infrastructure, support services, common controls, and external
dependencies).
- Mission/business process-specific characterization of adversarial and non-adversarial threatsources.
From Tier 3: (Information system level)

Yes

Yes

Yes

- Threat source information and guidance specific to Tier 3 (e.g., threats related to information
systems, information technologies, information system components, applications, networks,
environments of operation).
- Information system-specific characterization of adversarial and non-adversarial threat sources.

APPENDIX D

Yes

via
RAR

via
RAR

via
peer
sharing

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Guide for Conducting Risk Assessments________________________________________________________________________________________________TABLE D-2: TAXONOMY OF THREAT SOURCES

Type of Threat Source

Description

Characteristics

ADVERSARIAL- Individual- Outsider- Insider- Trusted Insider- Privileged Insider- Group- Ad hoc- Established- Organization- Competitor- Supplier- Partner- Customer- Nation-State

Individuals, groups, organizations, or states that seek toexploit the organization’s dependence on cyber
resources (i.e., information in electronic form, informationand communications technologies, and thecommunications and information-handling capabilities
provided by those technologies).

Capability, Intent, Targeting

ACCIDENTAL- User- Privileged User/Administrator

Erroneous actions taken by individuals in the course of
executing their everyday responsibilities.

Range of effects

STRUCTURAL- Information Technology (IT) Equipment- Storage- Processing- Communications- Display- Sensor- Controller- Environmental Controls- Temperature/Humidity Controls- Power Supply- Software- Operating System- Networking- General-Purpose Application- Mission-Specific Application

Failures of equipment, environmental controls, orsoftware due to aging, resource depletion, or othercircumstances which exceed expected operating
parameters.

Range of effects

ENVIRONMENTAL- Natural or man-made disaster- Fire- Flood/Tsunami- Windstorm/Tornado- Hurricane- Earthquake- Bombing- Overrun- Unusual Natural Event (e.g., sunspots)- Infrastructure Failure/Outage- Telecommunications- Electrical Power

Natural disasters and failures of critical infrastructures on
which the organization depends, but which are outside
the control of the organization.

Range of effects

APPENDIX D

Note: Natural and man-made disasters can also becharacterized in terms of their severity and/or duration.
However, because the threat source and the threat eventare strongly identified, severity and duration can be
included in the description of the threat event (e.g.,
Category 5 hurricane causes extensive damage to thefacilities housing mission-critical systems, making thosesystems unavailable for three weeks).

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Qualitative
ValuesSemi-Quantitative
ValuesDescription

Very High

96-10010

The adversary has a very sophisticated level of expertise, is well-resourced, and can generate
opportunities to support multiple successful, continuous, and coordinated attacks.

High

80-95

8

The adversary has a sophisticated level of expertise, with significant resources and opportunities
to support multiple successful coordinated attacks.

Moderate

21-79

5

The adversary has moderate resources, expertise, and opportunities to support multiple successful
attacks.

Low

5-20

2

The adversary has limited resources, expertise, and opportunities to support a successful attack.

Very Low

0-4

0

The adversary has very limited resources, expertise, and opportunities to support a successful
attack.

TABLE D-4: ASSESSMENT SCALE – CHARACTERISTICS OF ADVERSARY INTENT
Qualitative
ValuesVery HighHigh

Semi-Quantitative
Values96-10080-95

Description

10

The adversary seeks to undermine, severely impede, or destroy a core mission or business
function, program, or enterprise by exploiting a presence in the organization’s information systems
or infrastructure. The adversary is concerned about disclosure of tradecraft only to the extent that it
would impede its ability to complete stated goals.

8

The adversary seeks to undermine/impede critical aspects of a core mission or business function,
program, or enterprise, or place itself in a position to do so in the future, by maintaining a presencein the organization’s information systems or infrastructure. The adversary is very concerned aboutminimizing attack detection/disclosure of tradecraft, particularly while preparing for future attacks.

Moderate

21-79

5

The adversary seeks to obtain or modify specific critical or sensitive information or usurp/disrupt
the organization’s cyber resources by establishing a foothold in the organization’s information
systems or infrastructure. The adversary is concerned about minimizing attack detection/disclosureof tradecraft, particularly when carrying out attacks over long time periods. The adversary is willingto impede aspects of the organization’s missions/business functions to achieve these ends.

Low

5-20

2

The adversary actively seeks to obtain critical or sensitive information or to usurp/disrupt theorganization’s cyber resources, and does so without concern about attack detection/disclosure of
tradecraft.

Very Low

0-4

0

The adversary seeks to usurp, disrupt, or deface the organization’s cyber resources, and does so
without concern about attack detection/disclosure of tradecraft.

TABLE D-5: ASSESSMENT SCALE – CHARACTERISTICS OF ADVERSARY TARGETING
Qualitative
ValuesSemi-Quantitative
ValuesDescription

Very High

96-10010

The adversary analyzes information obtained via reconnaissance and attacks to target persistently
a specific organization, enterprise, program, mission or business function, focusing on specifichigh-value or mission-critical information, resources, supply flows, or functions; specific employees
or positions; supporting infrastructure providers/suppliers; or partnering organizations.

High

80-95

8

The adversary analyzes information obtained via reconnaissance to target persistently a specificorganization, enterprise, program, mission or business function, focusing on specific high-value or
mission-critical information, resources, supply flows, or functions, specific employees supporting
those functions, or key positions.

Moderate

21-79

5

The adversary analyzes publicly available information to target persistently specific high-valueorganizations (and key positions, such as Chief Information Officer), programs, or information.

Low

5-20

2

The adversary uses publicly available information to target a class of high-value organizations orinformation, and seeks targets of opportunity within that class.

Very Low

0-4

0

The adversary may or may not target any specific organizations or classes of organizations.

APPENDIX D

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Qualitative
ValuesSemi-Quantitative
ValuesDescription

Very High

96-10010

The effects of the error, accident, or act of nature are sweeping, involving almost all of the cyber
resources of the [Tier 3: information systems; Tier 2: mission/business processes or EA segments,
common infrastructure, or support services; Tier 1: organization/governance structure].

High

80-95

8

The effects of the error, accident, or act of nature are extensive, involving most of the cyber
resources of the [Tier 3: information systems; Tier 2: mission/business processes or EA segments,
common infrastructure, or support services; Tier 1: organization/governance structure], including
many critical resources.

Moderate

21-79

5

The effects of the error, accident, or act of nature are wide-ranging, involving a significant portionof the cyber resources of the [Tier 3: information systems; Tier 2: mission/business processes or
EA segments, common infrastructure, or support services; Tier 1: organization/governancestructure], including some critical resources.

Low

5-20

2

The effects of the error, accident, or act of nature are limited, involving some of the cyber
resources of the [Tier 3: information systems; Tier 2: mission/business processes or EA segments,
common infrastructure, or support services; Tier 1: organization/governance structure], butinvolving no critical resources.

0

The effects of the error, accident, or act of nature are minimal, involving few if any of the cyber
resources of the [Tier 3: information systems; Tier 2: mission/business processes or EA segments,
common infrastructure, or support services; Tier 1: organization/governance structure], andinvolving no critical resources.

Very Low

0-4

TABLE D-7: TEMPLATE – IDENTIFICATION OF ADVERSARIAL THREAT SOURCES

Identifier

Threat Source
Source of Information

In
Scope

Capability

IntentTargeting

Organization-defined

Table D-2 and Task 1-4
orOrganization-defined

Yes / No

Table D-3
or
Organization-defined

Table D-4
orOrganization-defined

Table D-5
or
Organization-defined

TABLE D-8: TEMPLATE – IDENTIFICATION OF NON-ADVERSARIAL THREAT SOURCES

Identifier

Threat Source
Source of Information

In
Scope

Range of Effects

Organization-defined

Table D-2 and Task 1-4
orOrganization-defined

Yes / No

Table D-6
orOrganization-defined

APPENDIX D

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APPENDIX E

THREAT EVENTSREPRESENTATIVE THREAT EVENTS INITIATED BY THREAT SOURCES

T

his appendix provides: (i) a description of potentially useful inputs to the threat event
identification task; (ii) representative examples of adversarial threat events expressed astactics, techniques, and procedures (TTPs) and non-adversarial threat events; (iii) an
exemplary assessment scale for the relevance of those threat events; and (iv) templates forsummarizing and documenting the results of the threat identification Task 2-2. Organizations caneliminate certain threat events from further consideration if no adversary with the necessary
capability has been identified. 51 Organizations can also modify the threat events provided todescribe specific TTPs with sufficient detail 52 and at the appropriate classification level. 53
Organizations can use the representative threat events and predicated/expected values for the
relevance of those events as a starting point with tailoring to adjust for any organization-specificconditions. Table E-5, an output from Task 2-2, provides relevant inputs to the risk tables inAppendix I.
TABLE E-1: INPUTS – THREAT EVENT IDENTIFICATION
Provided To

Description
From Tier 1: (Organization level)

Tier 1

Tier 2

No

Yes

Yes

- Sources of threat information deemed to be credible (e.g., open source and/or classified threat
reports, previous risk/threat assessments. (Section 3.1, Task 1-4.)- Threat event information and guidance specific to Tier 1 (e.g., threats related to organizational
governance, core missions/business functions, external mission/business relationships,
management/operational policies, procedures, and structures).
- Exemplary adversarial threat events, annotated by the organization, if necessary. (Table E-2)
- Exemplary non-adversarial threat events, annotated by the organization, if necessary. (Table E-3)
- Assessment scale for assessing the relevance of threat events, annotated by the organization, if
necessary. (Table E-4)
- Threat events identified in previous risk assessments, if appropriate.
From Tier 2: (Mission/business process level)

Tier 3
Yes

If notprovidedby Tier 2

Via
RAR

Yes

Via
Peer
Sharing

Yes- Threat event information and guidance specific to Tier 2 (e.g., threats related to mission/businessprocesses, EA segments, common infrastructure, support services, common controls, and external
dependencies).
- Mission/business process-specific characterization of adversarial and non-adversarial threat events.
From Tier 3: (Information system level)

Yes

Yes

Yes

- Threat event information and guidance specific to Tier 3 (e.g., threats related to information systems,
information technologies, information system components, applications, networks, environments ofoperation).
- Information system-specific characterization of adversarial and non-adversarial threat events.
- Incident reports.

Via
RAR

Via
RAR

Via
Peer
Sharing

51

Each entry in Table E-2 implicitly assumes a level of adversary capability, intent, and targeting. Depending on the
results of threat source identification, some entries could be determined to be irrelevant, while other entries could be
combined. In addition, some entries could be rewritten in terms of an organization’s enterprise architecture.
52
The level of detail of TTPs is established as part of the organizational risk frame. The level of detail in Table E-2 isintended to support risk assessments at all three tiers, and to be tailorable to include additional details, as necessary.
More detailed descriptions of threat events that exploit software, for example, can be found in the Common Attack
Pattern Enumeration and Classification (CAPEC) site at http://capec.mitre.org.
53

The threat events in Table E-2 are provided at the unclassified level. Additional threat events at the classified level
are available from selected federal agencies to individuals with appropriate security clearances and need to know.

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Threat Events

54

Description(Characterized by TTPs)

Perform reconnaissance and gather information.
Perform perimeter network reconnaissance/scanning.

Adversary uses commercial or free software to scan organizational perimeters to
obtain a better understanding of the information technology infrastructure andimprove the ability to launch successful attacks.

Perform network sniffing of exposed networks.

Adversary with access to exposed wired or wireless data channels used to transmit
information, uses network sniffing to identify components, resources, andprotections.

Gather information using open source discovery oforganizational information.

Adversary mines publically accessible information to gather information aboutorganizational information systems, business processes, users or personnel, or
external relationships that the adversary can subsequently employ in support of an
attack.

Perform reconnaissance and surveillance of targetedorganizations.

Adversary uses various means (e.g., scanning, physical observation) over time to
examine and assess organizations and ascertain points of vulnerability.

Perform malware-directed internal reconnaissance.

Adversary uses malware installed inside the organizational perimeter to identify
targets of opportunity. Because the scanning, probing, or observation does not crossthe perimeter, it is not detected by externally placed intrusion detection systems.
Craft or create attack tools.

Craft phishing attacks.

Adversary counterfeits communications from a legitimate/trustworthy source toacquire sensitive information such as usernames, passwords, or SSNs. Typicalattacks occur via email, instant messaging, or comparable means; commonly
directing users to websites that appear to be legitimate sites, while actually stealing
the entered information.

Craft spear phishing attacks.

Adversary employs phishing attacks targeted at high value targets (e.g., seniorleaders/executives).

Craft attacks specifically based on deployed information
technology environment.

Adversary develops attacks (e.g., crafts targeted malware) that take advantage ofadversary knowledge of the organizational information technology environment.

Create counterfeit/spoof website.

Adversary creates duplicates of legitimate websites; when users visit a counterfeit
site, the site can gather information or download malware.

Craft counterfeit certificates.

Adversary counterfeits or compromises a certificate authority, so that malware orconnections will appear legitimate.

Create and operate false front organizations to inject
malicious components into the supply chain.

Adversary creates false front organizations with the appearance of legitimate
suppliers in the critical life-cycle path that then inject corrupted/malicious information
system components into the organizational supply chain.

Deliver/insert/install malicious capabilities.
Deliver known malware to internal organizational
information systems (e.g., virus via email).

Adversary uses common delivery mechanisms (e.g., email) to install/insert known
malware (e. g., malware whose existence is known) into organizational information
systems.

Deliver modified malware to internal organizational
information systems.

Adversary uses more sophisticated delivery mechanisms than email (e.g., web
traffic, instant messaging, FTP) to deliver malware and possibly modifications ofknown malware to gain access to internal organizational information systems.

Deliver targeted malware for control of internal systems
and exfiltration of data.

Adversary installs malware that is specifically designed to take control of internalorganizational information systems, identify sensitive information, exfiltrate theinformation back to adversary, and conceal these actions.

Deliver malware by providing removable media.

Adversary places removable media (e.g., flash drives) containing malware inlocations external to organizational physical perimeters but where employees arelikely to find the media (e.g., facilities parking lots, exhibits at conferences attended
by employees) and use it on organizational information systems.

54
While not restricted to the APT as a threat source, the threat events in Table E-2 generally follow the flow of an APT
campaign. Within each stage in a campaign, similar events are listed in order of adversary capability.

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Threat Events

Description(Characterized by TTPs)

Insert untargeted malware into downloadable software
and/or into commercial information technology products.

Adversary corrupts or inserts malware into common freeware, shareware orcommercial information technology products. Adversary is not targeting specificorganizations, simply looking for entry points into internal organizational information
systems. Note that this is particularly a concern for mobile applications.

Insert targeted malware into organizational information
systems and information system components.

Adversary inserts malware into organizational information systems and information
system components (e.g., commercial information technology products), specificallytargeted to the hardware, software, and firmware used by organizations (based on
knowledge gained via reconnaissance).

Insert specialized malware into organizational
information systems based on system configurations.

Adversary inserts specialized, non-detectable, malware into organizational
information systems based on system configurations, specifically targeting criticalinformation system components based on reconnaissance and placement withinorganizational information systems.

Insert counterfeit or tampered hardware into the supply
chain.

Adversary intercepts hardware from legitimate suppliers. Adversary modifies the
hardware or replaces it with faulty or otherwise modified hardware.

Insert tampered critical components into organizational
systems.

Adversary replaces, though supply chain, subverted insider, or some combination
thereof, critical information system components with modified or corrupted
components.

Install general-purpose sniffers on organizationcontrolled information systems or networks.

Adversary installs sniffing software onto internal organizational information systems
or networks.

Install persistent and targeted sniffers on organizational
information systems and networks.

Adversary places within internal organizational information systems or networks
software designed to (over a continuous period of time) collect (sniff) network traffic.

Insert malicious scanning devices (e.g., wirelesssniffers) inside facilities.

Adversary uses postal service or other commercial delivery services to deliver toorganizational mailrooms a device that is able to scan wireless communications
accessible from within the mailrooms and then wirelessly transmit information backto adversary.

Insert subverted individuals into organizations.

Adversary places individuals within organizations who are willing and able to carryout actions to cause harm to organizational missions/business functions.

Insert subverted individuals into privileged positions inorganizations.

Adversary places individuals in privileged positions within organizations who arewilling and able to carry out actions to cause harm to organizational
missions/business functions. Adversary may target privileged functions to gain
access to sensitive information (e.g., user accounts, system files, etc.) and mayleverage access to one privileged capability to get to another capability.
Exploit and compromise.

Exploit physical access of authorized staff to gain
access to organizational facilities.

Adversary follows (“tailgates”) authorized individuals into secure/controlled locations
with the goal of gaining access to facilities, circumventing physical security checks.

Exploit poorly configured or unauthorized information
systems exposed to the Internet.

Adversary gains access through the Internet to information systems that are notauthorized for Internet connectivity or that do not meet organizational configuration
requirements.

Exploit split tunneling.

Adversary takes advantage of external organizational or personal information
systems (e.g., laptop computers at remote locations) that are simultaneously
connected securely to organizational information systems or networks and tononsecure remote connections.

Exploit multi-tenancy in a cloud environment.

Adversary, with processes running in an organizationally-used cloud environment,takes advantage of multi-tenancy to observe behavior of organizational processes,
acquire organizational information, or interfere with the timely or correct functioningof organizational processes.

Exploit known vulnerabilities in mobile systems (e.g.,
laptops, PDAs, smart phones).

Adversary takes advantage of fact that transportable information systems areoutside physical protection of organizations and logical protection of corporate
firewalls, and compromises the systems based on known vulnerabilities to gather
information from those systems.

Exploit recently discovered vulnerabilities.

Adversary exploits recently discovered vulnerabilities in organizational information
systems in an attempt to compromise the systems before mitigation measures areavailable or in place.

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Threat Events

Description(Characterized by TTPs)

Exploit vulnerabilities on internal organizational
information systems.

Adversary searches for known vulnerabilities in organizational internal information
systems and exploits those vulnerabilities.

Exploit vulnerabilities using zero-day attacks.

Adversary employs attacks that exploit as yet unpublicized vulnerabilities. Zero-day
attacks are based on adversary insight into the information systems and applications
used by organizations as well as adversary reconnaissance of organizations.

Exploit vulnerabilities in information systems timed withorganizational mission/business operations tempo.

Adversary launches attacks on organizations in a time and manner consistent withorganizational needs to conduct mission/business operations.

Exploit insecure or incomplete data deletion in multitenant environment.

Adversary obtains unauthorized information due to insecure or incomplete datadeletion in a multi-tenant environment (e.g., in a cloud computing environment).

Violate isolation in multi-tenant environment.

Adversary circumvents or defeats isolation mechanisms in a multi-tenant
environment (e.g., in a cloud computing environment) to observe, corrupt, or denyservice to hosted services and information/data.

Compromise critical information systems via physicalaccess.

Adversary obtains physical access to organizational information systems and makes
modifications.

Compromise information systems or devices used
externally and reintroduced into the enterprise.

Adversary installs malware on information systems or devices while thesystems/devices are external to organizations for purposes of subsequently infecting
organizations when reconnected.

Compromise software of organizational criticalinformation systems.

Adversary inserts malware or otherwise corrupts critical internal organizational
information systems.

Compromise organizational information systems tofacilitate exfiltration of data/information.

Adversary implants malware into internal organizational information systems, where
the malware over time can identify and then exfiltrate valuable information.

Compromise mission-critical information.

Adversary compromises the integrity of mission-critical information, thus preventing
or impeding ability of organizations to which information is supplied, from carryingout operations.

Compromise design, manufacture, and/or distribution of
information system components (including hardware,
software, and firmware).

Adversary compromises the design, manufacture, and/or distribution of criticalinformation system components at selected suppliers.

Conduct an attack (i.e., direct/coordinate attack tools or activities).
Conduct communications interception attacks.

Adversary takes advantage of communications that are either unencrypted or use
weak encryption (e.g., encryption containing publically known flaws), targets thosecommunications, and gains access to transmitted information and channels.

Conduct wireless jamming attacks.

Adversary takes measures to interfere with wireless communications so as toimpede or prevent communications from reaching intended recipients.

Conduct attacks using unauthorized ports, protocols andservices.

Adversary conducts attacks using ports, protocols, and services for ingress andegress that are not authorized for use by organizations.

Conduct attacks leveraging traffic/data movement
allowed across perimeter.

Adversary makes use of permitted information flows (e.g., email communication,
removable storage) to compromise internal information systems, which allows
adversary to obtain and exfiltrate sensitive information through perimeters.

Conduct simple Denial of Service (DoS) attack.

Adversary attempts to make an Internet-accessible resource unavailable to intended
users, or prevent the resource from functioning efficiently or at all, temporarily orindefinitely.

Conduct Distributed Denial of Service (DDoS) attacks.

Adversary uses multiple compromised information systems to attack a single target,
thereby causing denial of service for users of the targeted information systems.

Conduct targeted Denial of Service (DoS) attacks.

Adversary targets DoS attacks to critical information systems, components, or
supporting infrastructures, based on adversary knowledge of dependencies.

Conduct physical attacks on organizational facilities.

Adversary conducts a physical attack on organizational facilities (e.g., sets a fire).

Conduct physical attacks on infrastructures supportingorganizational facilities.

Adversary conducts a physical attack on one or more infrastructures supportingorganizational facilities (e.g., breaks a water main, cuts a power line).

Conduct cyber-physical attacks on organizational
facilities.

Adversary conducts a cyber-physical attack on organizational facilities (e.g.,
remotely changes HVAC settings).

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Threat Events

Description(Characterized by TTPs)

Conduct data scavenging attacks in a cloudenvironment.

Adversary obtains data used and then deleted by organizational processes runningin a cloud environment.

Conduct brute force login attempts/password guessing
attacks.

Adversary attempts to gain access to organizational information systems by randomor systematic guessing of passwords, possibly supported by password cracking
utilities.

Conduct nontargeted zero-day attacks.

Adversary employs attacks that exploit as yet unpublicized vulnerabilities. Attacks
are not based on any adversary insights into specific vulnerabilities of organizations.

Conduct externally-based session hijacking.

Adversary takes control of (hijacks) already established, legitimate information
system sessions between organizations and external entities (e.g., users connectingfrom off-site locations).

Conduct internally-based session hijacking.

Adversary places an entity within organizations in order to gain access toorganizational information systems or networks for the express purpose of taking
control (hijacking) an already established, legitimate session either between
organizations and external entities (e.g., users connecting from remote locations) or
between two locations within internal networks.

Conduct externally-based network traffic modification(man in the middle) attacks.

Adversary, operating outside organizational systems, intercepts/eavesdrops on
sessions between organizational and external systems. Adversary then relays
messages between organizational and external systems, making them believe thatthey are talking directly to each other over a private connection, when in fact theentire communication is controlled by the adversary. Such attacks are of particularconcern for organizational use of community, hybrid, and public clouds.

Conduct internally-based network traffic modification(man in the middle) attacks.

Adversary operating within the organizational infrastructure intercepts and corrupts
data sessions.

Conduct outsider-based social engineering to obtain
information.

Externally placed adversary takes actions (e.g., using email, phone) with the intent
of persuading or otherwise tricking individuals within organizations into revealing
critical/sensitive information (e.g., personally identifiable information).

Conduct insider-based social engineering to obtain
information.

Internally placed adversary takes actions (e.g., using email, phone) so that
individuals within organizations reveal critical/sensitive information (e.g., mission
information).

Conduct attacks targeting and compromising personal
devices of critical employees.

Adversary targets key organizational employees by placing malware on theirpersonally owned information systems and devices (e.g., laptop/notebook
computers, personal digital assistants, smart phones). The intent is to takeadvantage of any instances where employees use personal information systems ordevices to handle critical/sensitive information.

Conduct supply chain attacks targeting and exploiting
critical hardware, software, or firmware.

Adversary targets and compromises the operation of software (e.g., throughmalware injections), firmware, and hardware that performs critical functions fororganizations. This is largely accomplished as supply chain attacks on bothcommercial off-the-shelf and custom information systems and components.

Achieve results (i.e., cause adverse impacts, obtain information)
Obtain sensitive information through network sniffing of
external networks.

Adversary with access to exposed wired or wireless data channels thatorganizations (or organizational personnel) use to transmit information (e.g., kiosks,
public wireless networks) intercepts communications.

Obtain sensitive information via exfiltration.

Adversary directs malware on organizational systems to locate and surreptitiouslytransmit sensitive information.

Cause degradation or denial of attacker-selected
services or capabilities.

Adversary directs malware on organizational systems to impair the correct andtimely support of organizational mission/business functions.

Cause deterioration/destruction of critical information
system components and functions.

Adversary destroys or causes deterioration of critical information systemcomponents to impede or eliminate organizational ability to carry out missions orbusiness functions. Detection of this action is not a concern.

Cause integrity loss by creating, deleting, and/or
modifying data on publicly accessible information
systems (e.g., web defacement).

Adversary vandalizes, or otherwise makes unauthorized changes to, organizational
websites or data on websites.

Cause integrity loss by polluting or corrupting critical
data.

Adversary implants corrupted and incorrect data in critical data, resulting in
suboptimal actions or loss of confidence in organizational data/services.

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Threat Events

Description(Characterized by TTPs)

Cause integrity loss by injecting false but believable data
into organizational information systems.

Adversary injects false but believable data into organizational information systems,
resulting in suboptimal actions or loss of confidence in organizational data/services.

Cause disclosure of critical and/or sensitive information
by authorized users.

Adversary induces (e.g., via social engineering) authorized users to inadvertently
expose, disclose, or mishandle critical/sensitive information.

Cause unauthorized disclosure and/or unavailability by
spilling sensitive information.

Adversary contaminates organizational information systems (including devices andnetworks) by causing them to handle information of a classification/sensitivity forwhich they have not been authorized. The information is exposed to individuals who
are not authorized access to such information, and the information system, device,or network is unavailable while the spill is investigated and mitigated.

Obtain information by externally located interception of
wireless network traffic.

Adversary intercepts organizational communications over wireless networks.
Examples include targeting public wireless access or hotel networking connections,and drive-by subversion of home or organizational wireless routers.

Obtain unauthorized access.

Adversary with authorized access to organizational information systems, gains
access to resources that exceeds authorization.

Obtain sensitive data/information from publicly
accessible information systems.

Adversary scans or mines information on publically accessible servers and web
pages of organizations with the intent of finding sensitive information.

Obtain information by opportunistically stealing or
scavenging information systems/components.

Adversary steals information systems or components (e. g., laptop computers ordata storage media) that are left unattended outside of the physical perimeters oforganizations, or scavenges discarded components.
Maintain a presence or set of capabilities.

Obfuscate adversary actions.

Adversary takes actions to inhibit the effectiveness of the intrusion detection
systems or auditing capabilities within organizations.

Adapt cyber attacks based on detailed surveillance.

Adversary adapts behavior in response to surveillance and organizational security
measures.
Coordinate a campaign.

Coordinate a campaign of multi-staged attacks (e.g.,
hopping).

Adversary moves the source of malicious commands or actions from one
compromised information system to another, making analysis difficult.

Coordinate a campaign that combines internal andexternal attacks across multiple information systems andinformation technologies.

Adversary combines attacks that require both physical presence withinorganizational facilities and cyber methods to achieve success. Physical attack
steps may be as simple as convincing maintenance personnel to leave doors or
cabinets open.

Coordinate campaigns across multiple organizations toacquire specific information or achieve desired outcome.

Adversary does not limit planning to the targeting of one organization. Adversary
observes multiple organizations to acquire necessary information on targets ofinterest.

Coordinate a campaign that spreads attacks acrossorganizational systems from existing presence.

Adversary uses existing presence within organizational systems to extend theadversary’s span of control to other organizational systems including organizational
infrastructure. Adversary thus is in position to further undermine organizational
ability to carry out missions/business functions.

Coordinate a campaign of continuous, adaptive, andchanging cyber attacks based on detailed surveillance.

Adversary attacks continually change in response to surveillance and organizational
security measures.

Coordinate cyber attacks using external (outsider),internal (insider), and supply chain (supplier) attack
vectors.

Adversary employs continuous, coordinated attacks, potentially using all three attack
vectors for the purpose of impeding organizational operations.

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Threat Event

Description

Spill sensitive
information

Authorized user erroneously contaminates a device, information system, or network by placing on it or sending to it
information of a classification/sensitivity which it has not been authorized to handle. The information is exposed toaccess by unauthorized individuals, and as a result, the device, system, or network is unavailable while the spill isinvestigated and mitigated.

Mishandling of critical
and/or sensitive
information byauthorized users

Authorized privileged user inadvertently exposes critical/sensitive information.

Incorrect privilege
settings

Authorized privileged user or administrator erroneously assigns a user exceptional privileges or sets privilege
requirements on a resource too low.

Communications
contention

Degraded communications performance due to contention.

Unreadable display

Display unreadable due to aging equipment.

Earthquake at primary
facility

Earthquake of organization-defined magnitude at primary facility makes facility inoperable.

Fire at primary facility

Fire (not due to adversarial activity) at primary facility makes facility inoperable.

Fire at backup facility

Fire (not due to adversarial activity) at backup facility makes facility inoperable or destroys backups of software,configurations, data, and/or logs.

Flood at primary
facility

Flood (not due to adversarial activity) at primary facility makes facility inoperable.

Flood at backup
facility

Flood (not due to adversarial activity) at backup facility makes facility inoperable or destroys backups of software,configurations, data, and/or logs.

Hurricane at primary
facility

Hurricane of organization-defined strength at primary facility makes facility inoperable.

Hurricane at backup
facility

Hurricane of organization-defined strength at backup facility makes facility inoperable or destroys backups of software,configurations, data, and/or logs.

Resource depletion

Degraded processing performance due to resource depletion.

Introduction ofvulnerabilities into
software products

Due to inherent weaknesses in programming languages and software development environments, errors andvulnerabilities are introduced into commonly used software products.

Disk error

Corrupted storage due to a disk error.

Pervasive disk error

Multiple disk errors due to aging of a set of devices all acquired at the same time, from the same supplier.

Windstorm/tornado atprimary facility

Windstorm/tornado of organization-defined strength at primary facility makes facility inoperable.

Windstorm/tornado at
backup facility

Windstorm/tornado of organization-defined strength at backup facility makes facility inoperable or destroys backups ofsoftware, configurations, data, and/or logs.

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Value

Description

Confirmed

The threat event or TTP has been seen by the organization.

Expected

The threat event or TTP has been seen by the organization’s peers or partners.

Anticipated

The threat event or TTP has been reported by a trusted source.

Predicted

The threat event or TTP has been predicted by a trusted source.

Possible

The threat event or TTP has been described by a somewhat credible source.

N/A

The threat event or TTP is not currently applicable. For example, a threat event or TTP could assume specific technologies,
architectures, or processes that are not present in the organization, mission/business process, EA segment, or information
system; or predisposing conditions that are not present (e.g., location in a flood plain). Alternately, if the organization is using
detailed or specific threat information, a threat event or TTP could be deemed inapplicable because information indicates thatno adversary is expected to initiate the threat event or use the TTP.
TABLE E-5: TEMPLATE – IDENTIFICATION OF THREAT EVENTS

Identifier

Threat Event
Source of Information

Threat Source

Relevance

Organization-defined

Table E-2, Table E-3, Task 1-4
orOrganization-defined

Table D-7, Table D-8
orOrganization-defined

Table E-4
orOrganizationdefined

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APPENDIX FVULNERABILITIES AND PREDISPOSING CONDITIONSRISK FACTORS AFFECTING THE LIKELIHOOD OF SUCCESSFUL THREAT EXPLOITATIONT

his appendix provides: (i) a description of potentially useful inputs to the vulnerability andpredisposing condition identification task; (ii) an exemplary taxonomy of predisposing
conditions; (iii) exemplary assessment scales for assessing the severity of vulnerabilities
and the pervasiveness of predisposing conditions; and (iv) a set of templates for summarizing anddocumenting the results of the vulnerability and predisposing condition identification task. The
taxonomy and assessment scales in this appendix can be used by organizations as a starting pointwith appropriate tailoring to adjust for any organization-specific conditions. Tables F-3 and F-6,
outputs from Task 2-3, provide relevant inputs to the risk tables in Appendix I.
TABLE F-1: INPUTS – VULNERABILITIES AND PREDISPOSING CONDITIONSProvided To

Description
From Tier 1 (Organization level)

Tier 1

Tier 2

No

Yes

Yes

- Sources of vulnerability information deemed to be credible (e.g., open source and/or classified
vulnerabilities, previous risk/vulnerability assessments, Mission and/or Business Impact Analyses).
(Section 3.1, Task 1-4.)- Vulnerability information and guidance specific to Tier 1 (e.g., vulnerabilities related to organizational
governance, core missions/business functions, management/operational policies, procedures, andstructures, external mission/business relationships).
- Taxonomy of predisposing conditions, annotated by the organization, if necessary. (Table F-4)
- Characterization of vulnerabilities and predisposing conditions.
- Assessment scale for assessing the severity of vulnerabilities, annotated by the organization, if
necessary. (Table F-2)
- Assessment scale for assessing the pervasiveness of predisposing conditions, annotated by theorganization, if necessary. (Table F-5)
- Business Continuity Plan, Continuity of Operations Plan for the organization, if such plans aredefined for the entire organization.
From Tier 2: (Mission/business process level)

Tier 3
Yes

If notprovidedby Tier 2

Via
RAR

Yes

Via
Peer
SharingYes- Vulnerability information and guidance specific to Tier 2 (e.g., vulnerabilities related to organizational
mission/business processes, EA segments, common infrastructure, support services, common
controls, and external dependencies).
- Business Continuity Plans, Continuity of Operations Plans for mission/business processes, if suchplans are defined for individual processes or business units.
From Tier 3: (Information system level)

Yes

Yes

Yes

- Vulnerability information and guidance specific to Tier 3 (e.g., vulnerabilities related to information
systems, information technologies, information system components, applications, networks,
environments of operation).
- Security assessment reports (i.e., deficiencies in assessed controls identified as vulnerabilities).
- Results of monitoring activities (e.g., automated and nonautomated data feeds).
- Vulnerability assessments, Red Team reports, or other reports from analyses of information systems,
subsystems, information technology products, devices, networks, or applications.
- Contingency Plans, Disaster Recovery Plans, Incident Reports.
- Vendor/manufacturer vulnerability reports.

APPENDIX F

Via
RAR

Via
RAR

Via
Peer
Sharing

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Qualitative
ValuesVery HighSemi-Quantitative
Values96-100

10

High

80-95

8

Moderate

21-79

5

Low

5-20

2

Very Low

0-4

0

Description
The vulnerability is exposed and exploitable, and its exploitation could result in severe impacts.
Relevant security control or other remediation is not implemented and not planned; or no security
measure can be identified to remediate the vulnerability.
The vulnerability is of high concern, based on the exposure of the vulnerability and ease of
exploitation and/or on the severity of impacts that could result from its exploitation.
Relevant security control or other remediation is planned but not implemented; compensating
controls are in place and at least minimally effective.
The vulnerability is of moderate concern, based on the exposure of the vulnerability and ease of
exploitation and/or on the severity of impacts that could result from its exploitation.
Relevant security control or other remediation is partially implemented and somewhat effective.
The vulnerability is of minor concern, but effectiveness of remediation could be improved.
Relevant security control or other remediation is fully implemented and somewhat effective.
The vulnerability is not of concern.
Relevant security control or other remediation is fully implemented, assessed, and effective.

TABLE F-3: TEMPLATE – IDENTIFICATION OF VULNERABILITIES

Identifier

Organizationdefined

APPENDIX F

Vulnerability
Source of Information

Vulnerability
Severity

Task 2-3, Task 1-4
orOrganization-defined

Table F-2
orOrganization-defined

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Guide for Conducting Risk Assessments________________________________________________________________________________________________TABLE F-4: TAXONOMY OF PREDISPOSING CONDITIONSType of Predisposing Condition

Description

INFORMATION-RELATED- Classified National Security Information- Compartments- Controlled Unclassified Information- Personally Identifiable Information- Special Access Programs- Agreement-Determined- NOFORN- Proprietary

Needs to handle information (as it is created, transmitted, stored,
processed, and/or displayed) in a specific manner, due to its sensitivity(or lack of sensitivity), legal or regulatory requirements, and/or contractualor other organizational agreements.

TECHNICAL- Architectural- Compliance with technical standards- Use of specific products or product lines- Solutions for and/or approaches to user-based collaborationand information sharing- Allocation of specific security functionality to common controls- Functional- Networked multiuser- Single-user- Stand-alone / nonnetworked- Restricted functionality (e.g., communications, sensors,
embedded controllers)Needs to use technologies in specific ways.

OPERATIONAL / ENVIRONMENTAL- Mobility- Fixed-site (specify location)- Semi-mobile- Land-based, Airborne, Sea-based, Space-based- Mobile (e.g., handheld device)- Population with physical and/or logical access to componentsof the information system, mission/business process, EA segment- Size of population- Clearance/vetting of population

Ability to rely upon physical, procedural, and personnel controls provided
by the operational environment.

TABLE F-5: ASSESSMENT SCALE – PERVASIVENESS OF PREDISPOSING CONDITIONS
Qualitative
ValuesSemi-Quantitative
ValuesDescription

Very High

96-100

10

Applies to all organizational missions/business functions (Tier 1), mission/business processes(Tier 2), or information systems (Tier 3).

High

80-95

8

Applies to most organizational missions/business functions (Tier 1), mission/business processes(Tier 2), or information systems (Tier 3).

Moderate

21-79

5Applies to many organizational missions/business functions (Tier 1), mission/business processes(Tier 2), or information systems (Tier 3).

Low

5-20

2

Applies to some organizational missions/business functions (Tier 1), mission/business processes(Tier 2), or information systems (Tier 3).

Very Low

0-4

0Applies to few organizational missions/business functions (Tier 1), mission/business processes(Tier 2), or information systems (Tier 3).

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Identifier

Organizationdefined

APPENDIX F

Predisposing Condition
Source of Information

Pervasivenessof Condition

Table F-4, Task 1-4
orOrganization-defined

Table F-5
or
Organization-defined

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Special Publication 800-30

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APPENDIX G

LIKELIHOOD OF OCCURRENCE
DETERMINING THE LIKELIHOOD OF THREAT EVENTS CAUSING ADVERSE IMPACTS

T

his appendix provides: (i) a description of potentially useful inputs to the likelihood 55
determination task; and (ii) exemplary assessment scales for assessing the likelihood of
threat event initiation/occurrence, the likelihood of threat events resulting in adverse
impacts, and the overall likelihood of threat events being initiated or occurring and doing damage
to organizational operations, assets, or individuals. The assessment scales in this appendix can beused by organizations as a starting point with appropriate tailoring to adjust for any organizationspecific conditions. Tables G-2, G-3, G-4, and G-5, outputs from Task 2-4, provide relevant
inputs to the risk tables in Appendix I.
TABLE G-1: INPUTS – DETERMINATION OF LIKELIHOOD
Provided To

Description
From Tier 1 (Organization level)

Tier 1

Tier 2

No

Yes

Yes

- Likelihood information and guidance specific to Tier 1 (e.g., likelihood information related toorganizational governance, core missions/business functions, management/operational policies,
procedures, and structures, external mission/business relationships).
- Guidance on organization-wide levels of likelihood needing no further consideration.
- Assessment scale for assessing the likelihood of threat event initiation (adversarial threat events),
annotated by the organization, if necessary. (Table G-2)
- Assessment scale for assessing the likelihood of threat event occurrence (non-adversarial threat
events), annotated by the organization, if necessary. (Table G-3)
- Assessment scale for assessing the likelihood of threat events resulting in adverse impacts,
annotated by the organization, if necessary. (Table G-4)
- Assessment scale for assessing the overall likelihood of threat events being initiated or occurring andresulting in adverse impacts, annotated by the organization, if necessary. (Table G-5)
From Tier 2: (Mission/business process level)

Tier 3
Yes

If notprovidedby Tier 2

Yes

Via
Peer
Sharing

Yes- Likelihood information and guidance specific to Tier 2 (e.g., likelihood information related tomission/business processes, EA segments, common infrastructure, support services, common
controls, and external dependencies).

Via
RAR

From Tier 3: (Information system level)

Yes

Yes

Yes

- Likelihood information and guidance specific to Tier 3 (e.g., likelihood information related to
information systems, information technologies, information system components, applications,networks, environments of operation).
- Historical data on successful and unsuccessful cyber attacks; attack detection rates.
- Security assessment reports (i.e., deficiencies in assessed controls identified as vulnerabilities).
- Results of monitoring activities (e.g., automated and nonautomated data feeds).
- Vulnerability assessments, Red Team reports, or other reports from analyses of information systems,
subsystems, information technology products, devices, networks, or applications.
- Contingency Plans, Disaster Recovery Plans, Incident Reports.
- Vendor/manufacturer vulnerability reports.

Via
RAR

Via
RAR

Via
Peer
Sharing55

The term likelihood, as discussed in this guideline, is not likelihood in the strict sense of the term; rather, it is alikelihood score. Risk assessors do not define a likelihood function in the statistical sense. Instead, risk assessors assign
a score (or likelihood assessment) based on available evidence, experience, and expert judgment. Combinations offactors such as targeting, intent, and capability thus can be used to produce a score representing the likelihood of threat
initiation; combinations of factors such as capability and vulnerability severity can be used to produce a score
representing the likelihood of adverse impacts; and combinations of these scores can be used to produce an overall
likelihood score.

APPENDIX GPAGE G-1

Special Publication 800-30

Guide for Conducting Risk Assessments________________________________________________________________________________________________TABLE G-2: ASSESSMENT SCALE – LIKELIHOOD OF THREAT EVENT INITIATION (ADVERSARIAL)
Qualitative
ValuesSemi-Quantitative
ValuesDescription

Very High

96-10010

Adversary is almost certain to initiate the threat event.

High

80-95

8

Adversary is highly likely to initiate the threat event.

Moderate

21-79

5Adversary is somewhat likely to initiate the treat event.

Low

5-20

2

Adversary is unlikely to initiate the threat event.

Very Low0-4

0Adversary is highly unlikely to initiate the threat event.

TABLE G-3: ASSESSMENT SCALE – LIKELIHOOD OF THREAT EVENT OCCURRENCE (NON-ADVERSARIAL)
Qualitative
ValuesSemi-Quantitative
ValuesDescription

Very High

96-10010Error, accident, or act of nature is almost certain to occur; or occurs more than 100 times a year.

High

80-95

8

Error, accident, or act of nature is highly likely to occur; or occurs between 10-100 times a year.

Moderate

21-79

5

Error, accident, or act of nature is somewhat likely to occur; or occurs between 1-10 times a
year.

Low

5-20

2

Error, accident, or act of nature is unlikely to occur; or occurs less than once a year, but morethan once every 10 years.

Very Low0-40

Error, accident, or act of nature is highly unlikely to occur; or occurs less than once every 10
years.

TABLE G-4: ASSESSMENT SCALE – LIKELIHOOD OF THREAT EVENT RESULTING IN ADVERSE IMPACTS
Qualitative
ValuesSemi-Quantitative
ValuesDescription

Very High

96-10010

If the threat event is initiated or occurs, it is almost certain to have adverse impacts.

High

80-95

8

If the threat event is initiated or occurs, it is highly likely to have adverse impacts.

Moderate

21-79

5

If the threat event is initiated or occurs, it is somewhat likely to have adverse impacts.

Low

5-20

2

If the threat event is initiated or occurs, it is unlikely to have adverse impacts.

Very Low

0-4

0

If the threat event is initiated or occurs, it is highly unlikely to have adverse impacts.

TABLE G-5: ASSESSMENT SCALE – OVERALL LIKELIHOOD
Likelihood ofThreat Event
Initiation or
Occurrence

Very Low

Low

ModerateHigh

Very HighVery HighLow

ModerateHigh

Very HighVery High

High

Low

Moderate

ModerateHigh

Very High

Moderate

Low

Low

Moderate

Moderate

High

Low

Very Low

Low

Low

Moderate

Moderate

Very Low

Very Low

Very Low

Low

Low

Low

APPENDIX G

Likelihood Threat Events Result in Adverse Impacts

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APPENDIX H

IMPACT
EFFECTS OF THREAT EVENTS ON ORGANIZATIONS, INDIVIDUALS, AND THE NATIONT

his appendix provides: (i) a description of useful inputs to the impact determination task;(ii) representative examples of adverse impacts to organizational operations and assets,
individuals, other organizations, or the Nation; (iii) exemplary assessment scales forassessing the impact of threat events and the range of effect of threat events; and (iv) a templatefor summarizing and documenting the results of the impact determination Task 2-5. The
assessment scales in this appendix can be used as a starting point with appropriate tailoring toadjust for any organization-specific conditions. Table H-4, an output from Task 2-5, provides
relevant inputs to the risk tables in Appendix I.
TABLE H-1: INPUTS – DETERMINATION OF IMPACT
Provided To

Description
From Tier 1 (Organization level)

Tier 1

Tier 2

No

Yes

Yes

- Impact information and guidance specific to Tier 1 (e.g., impact information related to organizational
governance, core missions/business functions, management and operational policies, procedures,and structures, external mission/business relationships).
- Guidance on organization-wide levels of impact needing no further consideration.
- Identification of critical missions/business functions.
- Exemplary set of impacts, annotated by the organization, if necessary. (Table H-2)
- Assessment scale for assessing the impact of threat events, annotated by the organization, if
necessary. (Table H-3)
From Tier 2: (Mission/business process level)

Tier 3
Yes

If notprovidedby Tier 2

Via
RAR

Yes

Via
Peer
Sharing

Yes- Impact information and guidance specific to Tier 2 (e.g., impact information related tomission/business processes, EA segments, common infrastructure, support services, common
controls, and external dependencies).
- Identification of high-value assets.
From Tier 3: (Information system level)

Yes

Yes

Yes

- Impact information and guidance specific to Tier 3 (e.g., likelihood information affecting information
systems, information technologies, information system components, applications, networks,
environments of operation).
- Historical data on successful and unsuccessful cyber attacks; attack detection rates.
- Security assessment reports (i.e., deficiencies in assessed controls identified as vulnerabilities).
- Results of continuous monitoring activities (e.g., automated and nonautomated data feeds).
- Vulnerability assessments, Red Team reports, or other reports from analyses of information systems,
subsystems, information technology products, devices, networks, or applications.
- Contingency Plans, Disaster Recovery Plans, Incident Reports.

APPENDIX H

Via
RAR

Via
RAR

Via
Peer
Sharing

PAGE H-1

Special Publication 800-30

Guide for Conducting Risk Assessments________________________________________________________________________________________________TABLE H-2: EXAMPLES OF ADVERSE IMPACTS

Type of Impact

Impact

HARM TOOPERATIONS- Inability to perform current missions/business functions.
- In a sufficiently timely manner.
- With sufficient confidence and/or correctness.
- Within planned resource constraints.
- Inability, or limited ability, to perform missions/business functions in the future.
- Inability to restore missions/business functions.
- In a sufficiently timely manner.
- With sufficient confidence and/or correctness.
- Within planned resource constraints.
- Harms (e.g., financial costs, sanctions) due to noncompliance.
- With applicable laws or regulations.
- With contractual requirements or other requirements in other binding agreements (e.g., liability).
- Direct financial costs.
- Relational harms.
- Damage to trust relationships.
- Damage to image or reputation (and hence future or potential trust relationships).

HARM TO ASSETS- Damage to or loss of physical facilities.
- Damage to or loss of information systems or networks.
- Damage to or loss of information technology or equipment.
- Damage to or loss of component parts or supplies.
- Damage to or of loss of information assets.
- Loss of intellectual property.

HARM TO INDIVIDUALS- Injury or loss of life.
- Physical or psychological mistreatment.
- Identity theft.
- Loss of Personally Identifiable Information.
- Damage to image or reputation.

HARM TO OTHER
ORGANIZATIONS- Harms (e.g., financial costs, sanctions) due to noncompliance.
- With applicable laws or regulations.
- With contractual requirements or other requirements in other binding agreements.
- Direct financial costs.
- Relational harms.
- Damage to trust relationships.
- Damage to reputation (and hence future or potential trust relationships).

HARM TO THE NATION- Damage to or incapacitation of a critical infrastructure sector.
- Loss of government continuity of operations.
- Relational harms.
- Damage to trust relationships with other governments or with nongovernmental entities.
- Damage to national reputation (and hence future or potential trust relationships).
- Damage to current or future ability to achieve national objectives.
- Harm to national security.

APPENDIX H

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Guide for Conducting Risk Assessments________________________________________________________________________________________________TABLE H-3: ASSESSMENT SCALE – IMPACT OF THREAT EVENTS
Qualitative
ValuesSemi-Quantitative
ValuesVery HighHigh

Moderate

96-100

80-95

21-79

Description

10

The threat event could be expected to have multiple severe or catastrophic adverse effects onorganizational operations, organizational assets, individuals, other organizations, or the Nation.

8

The threat event could be expected to have a severe or catastrophic adverse effect onorganizational operations, organizational assets, individuals, other organizations, or the Nation. A
severe or catastrophic adverse effect means that, for example, the threat event might: (i) cause asevere degradation in or loss of mission capability to an extent and duration that the organization is
not able to perform one or more of its primary functions; (ii) result in major damage toorganizational assets; (iii) result in major financial loss; or (iv) result in severe or catastrophic harm
to individuals involving loss of life or serious life-threatening injuries.

5

The threat event could be expected to have a serious adverse effect on organizational operations,organizational assets, individuals other organizations, or the Nation. A serious adverse effectmeans that, for example, the threat event might: (i) cause a significant degradation in mission
capability to an extent and duration that the organization is able to perform its primary functions,but the effectiveness of the functions is significantly reduced; (ii) result in significant damage toorganizational assets; (iii) result in significant financial loss; or (iv) result in significant harm toindividuals that does not involve loss of life or serious life-threatening injuries.

Low

5-20

2

The threat event could be expected to have a limited adverse effect on organizational operations,organizational assets, individuals other organizations, or the Nation. A limited adverse effectmeans that, for example, the threat event might: (i) cause a degradation in mission capability to an
extent and duration that the organization is able to perform its primary functions, but theeffectiveness of the functions is noticeably reduced; (ii) result in minor damage to organizational
assets; (iii) result in minor financial loss; or (iv) result in minor harm to individuals.

Very Low

0-4

0

The threat event could be expected to have a negligible adverse effect on organizational
operations, organizational assets, individuals other organizations, or the Nation.

TABLE H-4: TEMPLATE – IDENTIFICATION OF ADVERSE IMPACTS

Type of Impact

ImpactAffected Asset

Maximum Impact

Table H-2
or
Organizationdefined

Table H-2
or
Organization-defined

Table H-3
or
Organization-defined

APPENDIX H

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APPENDIX IRISK DETERMINATIONASSESSING RISK TO ORGANIZATIONS, INDIVIDUALS, AND THE NATIONT

his appendix provides: (i) a description of potentially useful inputs to the risk
determination task including considerations for uncertainty of determinations; (ii)exemplary assessment scales for assessing the levels of risk; (iii) tables for describing
content (i.e., data inputs) for adversarial and non-adversarial risk determinations; and (iv)
templates for summarizing and documenting the results of the risk determination Task 2-6. The
assessment scales in this appendix can be used as a starting point with appropriate tailoring toadjust for any organization-specific conditions. Table I-5 (adversarial risk) and Table I-7 (nonadversarial risk) are outputs from Task 2-6.
TABLE I-1: INPUTS – RISK
Provided To

Description
From Tier 1 (Organization level)

Tier 1

Tier 2

No

Yes

Yes

Yes

If notprovidedby Tier 2- Sources of risk and uncertainty information identified for organization-wide use (e.g., specificinformation that may be useful in determining likelihoods such as adversary capabilities, intent, andtargeting objectives).
- Guidance on organization-wide levels of risk (including uncertainty) needing no further consideration.
- Criteria for uncertainty determinations.
- List of high-risk events from previous risk assessments.
- Assessment scale for assessing the level of risk as a combination of likelihood and impact, annotatedby the organization, if necessary. (Table I-2)
- Assessment scale for assessing level of risk, annotated by the organization, if necessary. (Table I-3)
From Tier 2: (Mission/business process level)

Tier 3

Via
RAR

Yes

Via
Peer
Sharing

Yes- Risk-related information and guidance specific to Tier 2 (e.g., risk and uncertainty information related
to mission/business processes, EA segments, common infrastructure, support services, common
controls, and external dependencies).
From Tier 3: (Information system level)

Yes

Yes

Yes

- Risk-related information and guidance specific to Tier 3 (e.g., likelihood information affecting
information systems, information technologies, information system components, applications,networks, environments of operation).

Via
RAR

Via
RAR

Via
Peer
Sharing

TABLE I-2: ASSESSMENT SCALE – LEVEL OF RISK (COMBINATION OF LIKELIHOOD AND IMPACT)

Likelihood(Threat Event Occurs
and Results inAdverse Impact)

Level of Impact

Very Low

Low

ModerateHigh

Very HighVery HighVery Low

Low

ModerateHigh

Very HighHigh

Very Low

Low

ModerateHigh

Very High

Moderate

Very Low

Low

Moderate

Moderate

High

Low

Very Low

Low

Low

Low

Moderate

Very Low

Very Low

Very Low

Very Low

Low

Low

APPENDIX I

PAGE I-1

Special Publication 800-30

Guide for Conducting Risk Assessments________________________________________________________________________________________________TABLE I-3: ASSESSMENT SCALE – LEVEL OF RISK
Qualitative
ValuesSemi-Quantitative
ValuesDescription

Very High

96-10010

Very high risk means that a threat event could be expected to have multiple severe orcatastrophic adverse effects on organizational operations, organizational assets, individuals,
other organizations, or the Nation.

High

80-95

8

High risk means that a threat event could be expected to have a severe or catastrophic adverse
effect on organizational operations, organizational assets, individuals, other organizations, or the
Nation.

Moderate

21-79

5Moderate risk means that a threat event could be expected to have a serious adverse effect onorganizational operations, organizational assets, individuals, other organizations, or the Nation.

Low

5-20

2

Low risk means that a threat event could be expected to have a limited adverse effect onorganizational operations, organizational assets, individuals, other organizations, or the Nation.

Very Low

0-4

0

Very low risk means that a threat event could be expected to have a negligible adverse effect onorganizational operations, organizational assets, individuals, other organizations, or the Nation.

APPENDIX I

PAGE I-2

Special Publication 800-30

Guide for Conducting Risk Assessments________________________________________________________________________________________________TABLE I-4: COLUMN DESCRIPTIONS FOR ADVERSARIAL RISK TABLE

ColumnHeading

Content

1

Threat Event

Identify threat event. (Task 2-2; Table E-1; Table E-2; Table E-5; Table I-5.)

2

Threat Sources

Identify threat sources that could initiate the threat event. (Task 2-1; Table D-1; Table D-2;
Table D-7; Table I-5.)

3

Capability

Assess threat source capability. (Task 2-1; Table D-3; Table D-7; Table I-5.)

4

IntentAssess threat source intent. (Task 2-1; Table D-4; Table D-7; Table I-5.)

5

TargetingAssess threat source targeting. (Task 2-1; Table D-5; Table D-7; Table I-5.)

6

Relevance

Determine relevance of threat event. (Task 2-2; Table E-1; Table E-4; Table E-5; Table I-5.)
If the relevance of the threat event does not meet the organization’s criteria for further
consideration, do not complete the remaining columns.

7

Likelihood of Attack Initiation

Determine likelihood that one or more of the threat sources initiates the threat event, taking into
consideration capability, intent, and targeting. (Task 2-4; Table G-1; Table G-2; Table I-5.)

8

Vulnerabilities andPredisposing Conditions

Identify vulnerabilities which could be exploited by threat sources initiating the threat event andthe predisposing conditions which could increase the likelihood of adverse impacts. (Task 2-5;
Table F-1; Table F-3; Table F-4; Table F-6; Table I-5.)

9Severity
Pervasiveness

Assess severity of vulnerabilities and pervasiveness of predisposing conditions. (Task 2-5;
Table F-1; Table F-2; Table F-5; Table F-6; Table I-5.)

10

Likelihood Initiated Attack
Succeeds

Determine the likelihood that the threat event, once initiated, will result in adverse impact,taking into consideration threat source capability, vulnerabilities, and predisposing conditions.
(Task 2-4; Table G-1; Table G-4; Table I-5.)

11

Overall Likelihood

Determine the likelihood that the threat event will be initiated and result in adverse impact (i.e.,
combination of likelihood of attack initiation and likelihood that initiated attack succeeds). (Task
2-4; Table G-1; Table G-5; Table I-5.)

12

Level of Impact

Determine the adverse impact (i.e., potential harm to organizational operations, organizational
assets, individuals, other organizations, or the Nation) from the threat event. (Task 2-5; Table
H-1, Table H-2; Table H-3; Table H-4; Table I-5.)

13

Risk

Determine the level of risk as a combination of likelihood and impact. (Task 2-6; Table I-1;
Table I-2; Table I-3; Table I-5.)

5

6

7

8

9

10

11

12

13

Vulnerabilities
andPredisposing
Conditions

Overall Likelihood

4

Likelihood InitiatedAttack Succeeds

3

Severity andPervasiveness2

Likelihood of
Attack Initiation

1

Relevance

TABLE I-5: TEMPLATE – ADVERSARIAL RISK

Level
of
ImpactRisk

APPENDIX I

TargetingThreatSources

IntentThreatEvent

Capability

Threat Source
Characteristics

PAGE I-3

Special Publication 800-30

Guide for Conducting Risk Assessments________________________________________________________________________________________________TABLE I-6: COLUMN DESCRIPTIONS FOR NON-ADVERSARIAL RISK TABLE

ColumnHeading

Content

1

Threat Event

Identify threat event. (Task 2-2; Table E-1; Table E-3; Table E-5; Table I-7.)

2

Threat Sources

Identify threat sources that could initiate the threat event. (Task 2-1; Table D-1; Table D-2;
Table D-8; Table I-7.)

3

Range of Effects

Identify the range of effects from the threat source. (Task 2-1; Table D-1; Table D-6; Table I-7.)

4

Relevance

Determine relevance of threat event. (Task 2-2; Table E-1; Table E-4; Table E-5; Table I-7.)
If the relevance of the threat event does not meet the organization’s criteria for further
consideration, do not complete the remaining columns.

5

Likelihood of Threat Event
Occurring

Determine the likelihood that the threat event will occur. (Task 2-4; Table G-1; Table G-3; Table
I-7.)

6

Vulnerabilities andPredisposing Conditions

Identify vulnerabilities which could be exploited by threat sources initiating the threat event andthe predisposing conditions which could increase the likelihood of adverse impacts. (Task 2-5;
Table F-1; Table F-3; Table F-4; Table F-6; Table I-7.)

7

Severity
Pervasiveness

Assess severity of vulnerabilities and pervasiveness of predisposing conditions. (Task 2-5; Table
F-1; Table F-2; Table F-5; Table F-6; Table I-5.)

8

Likelihood Threat Event
Results in Adverse Impact

Determine the likelihood that the threat event, once initiated, will result in adverse impact, taking
into consideration vulnerabilities and predisposing conditions. (Task 2-4; Table G-1; Table G-4;
Table I-7.)

9Overall Likelihood

Determine the likelihood that the threat event will occur and result in adverse impacts (i.e.,
combination of likelihood of threat occurring and likelihood that the threat event results inadverse impact). (Task 2-4; Table G-1; Table G-5; Table I-7.)

10

Level of Impact

Determine the adverse impact (i.e., potential harm to organizational operations, organizational
assets, individuals, other organizations, or the Nation) from the threat event. (Task 2-5; Table H1, Table H-2; Table H-3; Table H-4; Table I-7.)

11

Risk

Determine the level of risk as a combination of likelihood and impact. (Task 2-6; Table I-1; Table
I-2; Table I-3; Table I-7.)

ThreatSourcesRangeof
Effects

APPENDIX I

5

6

7

8

9

10

11

Vulnerabilities
andPredisposing
Conditions

Overall Likelihood

ThreatEvent

4

Likelihood Event
Results in Adverse
Impact3

Severity andPervasiveness2

Likelihood of
Event Occurring

1

Relevance

TABLE I-7: TEMPLATE – NON-ADVERSARIAL RISK

Level
of
ImpactRisk

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Guide for Conducting Risk Assessments________________________________________________________________________________________________

APPENDIX JINFORMING RISK RESPONSE
APPROACHES TO REFINING RISK ASSESSMENT RESULTS

A

risk assessment may identify a number of risks that have similar scores (e.g., 78, 82, 83)
or levels (e.g., moderate, high). When too many risks are clustered at or about the samevalue, organizations need a method to refine the presentation of risk assessment results,
prioritizing within sets of risks with similar values, to better inform the risk response componentof the risk management process. 56 Such a method should be associated with the mission/business
requirements of the organization, consistent with the organizational risk tolerance, and maximize
the use of available resources. Prioritization is a key component of risk-based protection andbecomes necessary when requirements cannot be fully satisfied or when resources do not allow
all risks to be mitigated within a reasonable time frame. To facilitate informed risk response
decisions by senior leaders/executives (e.g., why certain risks were or were not mitigated), therisk assessment results are annotated to enable those decision makers to know or obtain theanswers to the following questions about each risk in a set with similar scores:
Time FrameIn the event the identified risk materialized—•

How high would the immediate impact be to organizational operations (including mission,functions, image, or reputation), organizational assets, individuals, other organizations, or the
Nation?

•How high would the future impact be to organizational operations (including mission,functions, image, or reputation), organizational assets, individuals, other organizations, or the
Nation?

The answers to the above questions, together with the risk tolerance of the organization, provide
the basis for a risk prioritization that is based on current and future organizational needs. When
weighing immediate impacts versus future impacts, senior leaders must decide whether a criticalmission/business need today warrants jeopardizing the future capabilities of the organization.
Mission/business owners and mission/business subject matter experts can be consulted to obtainthe most complete and up-to-date information on mission/business impacts. Other subject matter
experts or stakeholder representatives can be consulted to obtain information on immediate versus
future impacts (e.g., consulting the Privacy Office for impacts to individuals).
Total Cumulative Impact•

What is the expected impact from a single occurrence of the threat?

•

If the risk can materialize more than once, what is the overall expected impact (i.e.,
cumulative loss) for the time period of concern?

Note that one aspect of the total impact to organizations is the cost of recovery from a loss ofconfidentiality, integrity, or availability.
56

The risk executive (function) provides policy-level guidance on organizational risk tolerance and other factors that
inform and guide the risk-based decisions of authorizing officials. This guidance can also influence the prioritization ofrisk responses including for example, mitigation activities.

APPENDIX JPAGE J-1

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Guide for Conducting Risk Assessments________________________________________________________________________________________________

Synergies Among Risks
If a risk materializes that is closely related to multiple risks, it is likely that a cluster of risks willmaterialize at or near the same time. Managing the adverse impact from one risk materializing
may be possible; managing multiple risks of high impact that materialize at the same time may
challenge the capacity of the organization and therefore needs to be managed much more closely.
The following questions address relationships among risks.
Will the materialization of a particular risk result in:•

A high likelihood or virtual certainty of other identified risks materializing?

•

A high likelihood or virtual certainty of other identified risks not materializing?

•No particular effect on other identified risks materializing?

If a risk is highly coupled to other risks or seen as likely to lead to other risks materializing(whether the risk is the cause or materializes concurrently), the risk should be given higher
priority than a risk that has no particular effect on other risks. If a risk materializing actually
decreases the likelihood of other risks materializing, then further analysis is warranted todetermine which risks become a lower priority to mitigate.
In conclusion, organizations can benefit significantly by refining risk assessment results in
preparation for the risk response step in the risk management process. During the risk response
step, which is described in NIST Special Publication 800-39, organizations: (i) analyze different
courses of action; (ii) conduct cost-benefit analyses; (iii) address scalability issues for large-scale
implementations; (iv) examine the interactions/dependencies among risk mitigation approaches(e.g., dependencies among security controls); and (v) assess other factors affecting organizational
missions/business functions. In addition, organizations address cost, schedule, and performanceissues associated with information systems and information technology infrastructure supportingorganizational missions/business functions.

CAUTIONARY NOTE
Organizations are cautioned that risk assessments are often not precise instruments of measurement
and reflect the limitations of the specific assessment methodologies, tools, and techniques employed—
as well as the subjectivity, quality, and trustworthiness of the data used. Risk determinations may bevery coarse due to the assessment approach selected, the uncertainty in the likelihood of occurrence
and impact values, and the potential mischaracterization of threats. Risks that are on the borderline
between bins using the organization-defined binning scales, must ultimately be assigned to one bin.
This determination could have a significant effect on the risk prioritization process. Thus, organizations
should incorporate as much information as practical on particular risks during the prioritization process
to ensure that the values for risks are appropriately determined (e.g., very low, low, moderate, high, veryhigh).

APPENDIX JPAGE J-2

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Guide for Conducting Risk Assessments________________________________________________________________________________________________

APPENDIX KRISK ASSESSMENT REPORTS
ESSENTIAL ELEMENTS OF INFORMATIONT

his appendix provides the essential elements of information that organizations can use tocommunicate the results of risk assessments. 57 Risk assessment results provide decision
makers with an understanding of the information security risk to organizational operations
and assets, individuals, other organizations, or the Nation that derive from the operation and useof organizational information systems and the environments in which those systems operate. The
essential elements of information in a risk assessment can be described in three sections of therisk assessment report (or whatever vehicle is chosen by organizations to convey the results of theassessment): (i) an executive summary; (ii) the main body containing detailed risk assessment
results; and (iii) supporting appendices.
Executive Summary•

List the date of the risk assessment.

•

Summarize the purpose of the risk assessment.

•

Describe the scope of the risk assessment.
-

For Tier 1 and Tier 2 risk assessments, identify: organizational governance structures
or processes associated with the assessment (e.g., risk executive [function], budget
process, acquisition process, systems engineering process, enterprise architecture,
information security architecture, organizational missions/business functions,
mission/business processes, information systems supporting the mission/businessprocesses).

-

For Tier 3 risk assessments, identify: the information system name and location(s),security categorization, and information system (i.e., authorization) boundary.

•State whether this is an initial or subsequent risk assessment. If a subsequent risk
assessment, state the circumstances that prompted the update and include a reference tothe previous Risk Assessment Report.

•

Describe the overall level of risk (e.g., Very Low, Low, Moderate, High, or Very High).

•

List the number of risks identified for each level of risk (e.g., Very Low, Low, Moderate,
High, or Very High).

Body of the Report•

Describe the purpose of the risk assessment, including questions to be answered by theassessment. For example:

57

The essential elements of information described in this appendix are informative and exemplary only and are notintended to require or promote a specific template for documenting risk assessment results. Organizations havemaximum flexibility in determining the type and the level of detail of information included in organizational risk
assessments and the associated reports. For example, Tier 1 and Tier 2 risk assessment results may be conveyed via an
executive briefing or dashboard, whereas Tier 3 risk assessment results may be conveyed via a risk assessment report(formal or informal depending on organizational preference). The essential elements of information for communicatingrisk assessment results can be modified accordingly to meet the needs of organizations conducting the assessments.

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Guide for Conducting Risk Assessments________________________________________________________________________________________________-How the use of a specific information technology would potentially change the risk
to organizational missions/business functions if employed in information systems
supporting those missions/business functions; or-

How the risk assessment results are to be used in the context of the RMF (e.g., an
initial risk assessment to be used in tailoring security control baselines and/or toguide and inform other decisions and serve as a starting point for subsequent risk
assessments; subsequent risk assessment to incorporate results of security control
assessments and inform authorization decisions; subsequent risk assessment tosupport the analysis of alternative courses of action for risk responses; subsequentrisk assessment based on risk monitoring to identify new threats or vulnerabilities;
subsequent risk assessments to incorporate knowledge gained from incidents or
attacks).

•

Identify assumptions and constraints.

•

Describe risk tolerance inputs to the risk assessment (including the range of consequences
to be considered).

•

Identify and describe the risk model and analytic approach; provide a reference or include
as an appendix, identifying risk factors, value scales, and algorithms for combining
values.

•Provide a rationale for any risk-related decisions during the risk assessment process.

•Describe the uncertainties within the risk assessment process and how those uncertainties
influence decisions.

•

If the risk assessment includes organizational missions/business functions, describe themissions/functions (e.g., mission/business processes supporting the missions/functions,interconnections and dependencies among related missions/business functions, andinformation technology that supports the missions/business functions).

•

If the risk assessment includes organizational information systems, describe the systems(e.g., missions/business functions the system is supporting, information flows to/from thesystems, and dependencies on other systems, shared services, or common infrastructures).

•

Summarize risk assessment results (e.g., using tables or graphs), in a form that enables
decision makers to quickly understand the risk (e.g., number of threat events for different
combinations of likelihood and impact, the relative proportion of threat events at different
risk levels).

•

Identify the time frame for which the risk assessment is valid (i.e., time frame for which
the assessment is intended to support decisions).

•

List the risks due to adversarial threats (see Table F-1).

•

List the risks due to non-adversarial threats (see Table F-2).

Appendices•

List references and sources of information.

•

List the team or individuals conducting the risk assessment including contact information.

•

List risk assessment details and any supporting evidence (e.g., Tables D-7, D-8, E-5, F-3,
F-6, H-4), as needed to understand and enable reuse of results (e.g., for reciprocity, forsubsequent risk assessments, to serve as input to Tier 1 and Tier 2 risk assessments).

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Guide for Conducting Risk Assessments________________________________________________________________________________________________

APPENDIX L

SUMMARY OF TASKSRISK ASSESSMENT TASKS AND ASSOCIATED RISK TABLESTABLE L-1: SUMMARY OF RISK ASSESSMENT TASKSTASKTASK DESCRIPTION

Step 1: Prepare for Risk Assessment
TASK 1-1
IDENTIFY PURPOSE
Section 3.1

TASK 1-2
IDENTIFY SCOPE

Identify the purpose of the risk assessment in terms of the information that theassessment is intended to produce and the decisions the assessment is intended tosupport.
Identify the scope of the risk assessment in terms of organizational applicability, timeframe supported, and architectural/technology considerations.

Section 3.1

TASK 1-3
IDENTIFY ASSUMPTIONSAND CONSTRAINTS

Identify the specific assumptions and constraints under which the risk assessment isconducted.

Section 3.1

TASK 1-4
IDENTIFY INFORMATIONSOURCES

Identify the sources of descriptive, threat, vulnerability, and impact information to be
used in the risk assessment.

Section 3.1

TASK 1-5
IDENTIFY RISK MODEL AND
ANALYTIC APPROACH

Identify the risk model and analytic approach to be used in the risk assessment.

Section 3.1

Step 2: Conduct Risk Assessment
TASK 2-1
IDENTIFY THREAT SOURCES
Section 3.2, Appendix D

TASK 2-2
IDENTIFY THREAT EVENTS

Identify and characterize threat sources of concern, including capability, intent, andtargeting characteristics for adversarial threats and range of effects for non-adversarial
threats.
Identify potential threat events, relevance of the events, and the threat sources that could
initiate the events.

Section 3.2, Appendix E

TASK 2-3
IDENTIFY VULNERABILITIES AND
PREDISPOSING CONDITIONS

Identify vulnerabilities and predisposing conditions that affect the likelihood that threat
events of concern result in adverse impacts.

Section 3.2, Appendix F

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Guide for Conducting Risk Assessments________________________________________________________________________________________________TASKTASK 2-4
DETERMINE LIKELIHOOD
Section 3.2, Appendix G

TASK 2-5
DETERMINE IMPACT
Section 3.2, Appendix H

TASK 2-6
DETERMINE RISKTASK DESCRIPTION
Determine the likelihood that threat events of concern result in adverse impacts,
considering: (i) the characteristics of the threat sources that could initiate the events; (ii)the vulnerabilities/predisposing conditions identified; and (iii) the organizational
susceptibility reflecting the safeguards/countermeasures planned or implemented to
impede such events.
Determine the adverse impacts from threat events of concern, considering: (i) the
characteristics of the threat sources that could initiate the events; (ii) thevulnerabilities/predisposing conditions identified; and (iii) the organizational susceptibility
reflecting the safeguards/countermeasures planned or implemented to impede such
events.
Determine the risk to the organization from threat events of concern considering: (i) the
impact that would result from the events; and (ii) the likelihood of the events occurring.

Section 3.2, Appendix I

Step 3: Communicate and Share Risk Assessment Results
TASK 3-1
COMMUNICATE RISKASSESSMENT RESULTS

Communicate risk assessment results to organizational decision makers to support risk
responses.

Section 3.3, Appendix K

TASK 3-2
SHARE RISK-RELATEDINFORMATION

Share risk-related information produced during the risk assessment with appropriateorganizational personnel.

Section 3.3

Step 4: Maintain Risk Assessment
TASK 4-1
MONITOR RISK FACTORS

Conduct ongoing monitoring of the risk factors that contribute to changes in risk toorganizational operations and assets, individuals, other organizations, or the Nation.

Section 3.4

TASK 4-2
UPDATE RISK ASSESSMENT

Update existing risk assessment using the results from ongoing monitoring of risk
factors.

Section 3.4

APPENDIX L

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