NIST Interagency Report 7275

Revision 2 

Specification for the 

Extensible Configuration 

Checklist Description Format 

(XCCDF) Version 1.1.3 

Neal Ziring 

Stephen D. Quinn 
Specification for the Extensible 

Configuration Checklist 

Description Format (XCCDF) 

Version 1.1.3 

Neal Ziring 

Stephen D. Quinn

NIST Interagency Report 7275 

Revision 2 

C O M P U T E R S E C U R I T Y

Computer Security Division 

Information Technology Laboratory 

National Institute of Standards and Technology 

Gaithersburg, MD 20899-8930 

May 2007 

U.S. Department of Commerce 

Carlos M. Gutierrez, Secretary 

Technology Administration 

Robert C. Cresanti, Under Secretary of Commerce for 

Technology 

National Institute of Standards and Technology 

William Jeffrey, Director 
SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Reports on Computer Systems Technology 

The Information Technology Laboratory (ITL) at the National Institute of Standards and Technology 

(NIST) promotes the U.S. economy and public welfare by providing technical leadership for the nation’s 

measurement and standards infrastructure. ITL develops tests, test methods, reference data, proof of 

concept implementations, and technical analysis to advance the development and productive use of 

information technology. ITL’s responsibilities include the development of technical, physical, 

administrative, and management standards and guidelines for the cost-effective security and privacy of 

sensitive unclassified information in Federal computer systems. This Interagency Report discusses ITL’s 

research, guidance, and outreach efforts in computer security and its collaborative activities with industry, 

government, and academic organizations. 

Certain commercial entities, equipment, or materials may be identified in this 

document in order to describe an experimental procedure or concept adequately. 

Such identification is not intended to imply recommendation or endorsement by the 

National Institute of Standards and Technology, nor is it intended to imply that the 

entities, materials, or equipment are necessarily the best available for the purpose. 

National Institute of Standards and Technology Interagency Report 7275 Revision 2 

126 pages (May 2007) 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Abstract 

This document specifies the data model and Extensible Markup Language (XML) representation 

for the Extensible Configuration Checklist Description Format (XCCDF) Version 1.1.3. An 

XCCDF document is a structured collection of security configuration rules for some set of target 

systems. The XCCDF specification is designed to support information interchange, document 

generation, organizational and situational tailoring, automated compliance testing, and 

compliance scoring. The specification also defines a data model and format for storing results of 

security guidance or checklist compliance testing. The intent of XCCDF is to provide a uniform 

foundation for expression of security checklists and other configuration guidance, and thereby 

foster more widespread application of good security practices. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Authority 

The National Institute of Standards and Technology (NIST) developed this document in 

furtherance of its statutory responsibilities under the Federal Information Security Management 

Act (FISMA) of 2002, Public Law 107-347. 

NIST is responsible for developing standards and guidelines, including minimum requirements, 

for providing adequate information security for all agency operations and assets; but such 

standards and guidelines shall not apply to national security 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 A-130, Appendix IV: Analysis of 

Key Sections. Supplemental information is provided in A-130, Appendix III. 

This guideline has been prepared for use by Federal agencies. It may be used by 

nongovernmental organizations on a voluntary basis and is not subject to copyright, though 

attribution is desired. 

Nothing in this document should be taken to contradict standards and guidelines made 

mandatory 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. 

Purpose and Scope 

The Cyber Security Research and Development Act of 2002 tasks NIST to “develop, and revise 

as necessary, a checklist setting forth settings and option selections that minimize the security 

risks associated with each computer hardware or software system that is, or is likely to become 

widely used within the Federal Government.” Such checklists, when developed correctly, 

accompanied with automated tools, and leveraged with high-quality security expertise, vendor 

product knowledge, and operational experience, can markedly reduce the vulnerability exposure 

of an organization. 

The XCCDF standardized XML format enables an automated provisioning of recommendations 

for minimum security controls for information systems categorized in accordance with NIST 

Special Publication (SP) 800-53, Recommended Security Controls for Federal Information 

Systems, and Federal Information Processing Standards (FIPS) 199, Standards for Security 

Categorization of Federal Information and Information Systems, to support Federal Information 

Security Management Act (FISMA) compliance efforts. 

To promote the use, standardization, and sharing of effective security checklists, NIST and the 

National Security Agency (NSA) have collaborated with representatives of private industry to 

develop the XCCDF specification. The specification is vendor-neutral, flexible, and suited for a 

wide variety of checklist applications. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Audience 

The primary audience of the XCCDF specification is government and industry security analysts, 

and industry security management product developers. NIST and NSA welcome feedback from 

these groups on improving the XCCDF specification. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Table of Contents 

1. Introduction............................................................................................................................ 1 

1.1. Background..................................................................................................................... 2 

1.2. Vision for Use................................................................................................................. 2 

1.3. Summary of Changes since Version 1.0......................................................................... 3 

2. Requirements ......................................................................................................................... 6 

2.1. Structure and Tailoring Requirements............................................................................ 8 

2.2. Inheritance and Inclusion Requirements......................................................................... 9 

2.3. Document and Report Formatting Requirements........................................................... 9 

2.4. Rule Checking Requirements ......................................................................................... 9 

2.5. Test Results Requirements............................................................................................ 10 

2.6. Metadata and Security Requirements ........................................................................... 11 

3. Data Model........................................................................................................................... 12 

3.1. Benchmark Structure .................................................................................................... 13 

3.2. Object Content Details.................................................................................................. 14 

3.3. Processing Models........................................................................................................ 32 

4. XML Representation............................................................................................................ 42 

4.1. XML Document General Considerations ..................................................................... 42 

4.2. XML Element Dictionary ............................................................................................. 43 

4.3. Handling Text and String Content ................................................................................ 73 

5. Conclusions.......................................................................................................................... 76 

6. Appendix A – XCCDF Schema........................................................................................... 77 

7. Appendix B – Sample Benchmark File ............................................................................. 107 

8. Appendix C – Pre-Defined URIs ....................................................................................... 114 

9. Appendix D – References.................................................................................................. 116 

10. Appendix E – Acronym List.............................................................................................. 117 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Acknowledgements 

The authors of this publication, Neal Ziring of the National Security Agency (NSA) and Stephen 

D. Quinn of the National Institute of Standards and Technology (NIST), would like to 

acknowledge the following individuals who contributed to the initial definition and development 

of the Extensible Configuration Checklist Description Format (XCCDF): David Proulx, Mike 

Michnikov, Andrew Buttner, Todd Wittbold, Adam Compton, George Jones, Chris Calabrese, 

John Banghart, Murugiah Souppaya, John Wack, Trent Pitsenbarger, and Robert Stafford. Peter 

Mell, Matthew Wojcik, and Karen Scarfone contributed to Revisions 1 and 2 of this document. 

David Waltermire was instrumental in supporting the development of XCCDF; he contributed 

many important concepts and constructs, performed a great deal of proofreading on this 

specification document, and provided critical input based on implementation experience. Ryan 

Wilson of Georgia Institute of Technology also made substantial contributions. Thanks also go 

to the Defense Information Systems Agency (DISA) Field Security Office (FSO) Vulnerability 

Management System (VMS)/Gold Disk team for extensive review and many suggestions. 

 

Trademark Information 

Cisco and IOS are registered trademarks of Cisco Systems, Inc. in the USA and other countries. 

Windows and Windows XP are registered trademarks of Microsoft Corporation in the USA and 

other countries. 

Solaris is a registered trademark of Sun Microsystems, Inc. 

OVAL is a trademark of The MITRE Corporation. 

All other names are registered trademarks or trademarks of their respective companies. 

Warnings 

SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 

INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 

MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY 

DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY 

DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 

DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 

GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 

INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 

WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 

OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 

EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

viii
SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

1. Introduction 

The Extensible Configuration Checklist Description Format (XCCDF) was originally intended to 

be used for technical security checklists. Although this is still the primary use of XCCDF, 

XCCDF also has extensions into non-technical applications (e.g., owner’s manuals, user guides, 

non-technical Federal Information Security Management Act [FISMA] controls, and items 

considered “manual procedures”). Although these non-technical applications were unintended, 

they are most welcome. Non-technical applications are outside the scope of this specification 

document. 

The security of an information technology (IT) system typically can be improved if the identified 

software flaws and configuration settings that affect security are properly addressed. The 

security of an IT system may be measured in a variety of ways; one operationally relevant 

method is determining conformance of the system configuration to a specified security baseline, 

guidance document, or checklist. These typically include criteria and rules for hardening a 

system against the most common forms of compromise and exploitation, and for reducing the 

exposed “attack surface” of a system. Many companies, government agencies, community 

groups, and product vendors generate and disseminate security guidance documents. While 

definition of the conditions under which a security setting should be applied can differ among the 

guidance documents, the underlying specification, test, and report formats used to identify and 

remediate said settings tend to be specialized and unique. 

Configuring a system to conform to specified security guidance (e.g., NIST Special Publication 

[SP] 800-68, Guidance for Securing Microsoft Windows XP Systems for IT 

Professionals: A NIST Security Configuration Checklist, any of the Defense Information Systems 

Agency [DISA] Secure Technology Implementation Guides [STIG] and subsequent checklists) 

or other security specification is a highly technical task. To aid system administrators, 

commercial and community developers have created automated tools that can both determine a 

system’s conformance to a specified guideline and provide or implement remediation measures. 

Many of these tools are data-driven in that they accept a security guidance specification in some 

program-readable form (e.g., XML, .inf, csv), and use it to perform the checks and tests 

necessary to measure conformance, generate reports, and perhaps remediate as directed. 

However, with rare exceptions, none of these tools (commercial or government developed) 

employ the same data formats. This unfortunate situation perpetuates a massive duplication of 

effort among security guidance providers and provides a barrier for content and report 

interoperability. 

This document describes a standard data model and processing discipline for supporting secure 

configuration and assessment. The requirements and goals are explained in the main content; 

however, in summary, this document addresses: 

• Document generation 

• Expression of policy-aware configuration rules 

• Support for conditionally applicable, complex, and compound rules 

• Support for compliance report generation and scoring 

• Support for customization and tailoring. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

The model and its XML representation are intended to be platform-independent and portable, to 

foster broad adoption and sharing of rules. The processing discipline of the format requires, for 

some uses, a service layer that can collect and store system information and perform simple 

policy-neutral tests against the system information; this is true for technical and non-technical 

applications of XCCDF. These conditions are described in detail below. The XML 

representation is expressed as an XML Schema in Appendix A. 

1.1. Background 

Today, groups promoting good security practices and system owners wishing to adopt them face 

an increasingly large and complex problem. As the number of IT systems increases, automated 

tools are necessary for uniform application of security rules and visibility into system status. 

These conditions have created a need for mechanisms that: 

• Ensure compliance to multiple policies (e.g., IT Systems subject to FISMA, STIG, 

and/or Health Insurance Portability and Accountability Act [HIPAA] compliance) 

• Permit faster, more cooperative, and more automated definition of security rules, 

procedures, guidance documents, alerts, advisories, and remediation measures 

• Permit fast, uniform, manageable administration of security checks and audits 

• Permit composition of security rules and tests from different community groups and 

vendors 

• Permit scoring, reporting, and tracking of security status and checklist conformance, 

both over distributed systems and over the same systems across their operational 

lifetimes 

• Foster development of interoperable community and commercial tools for creating and 

employing security guidance and checklist data. 

Today, such mechanisms exist only in some isolated niche areas (e.g., Microsoft Windows patch 

validation) and they support only narrow slices of security guidance compliance functionality. 

For example, patch-checking and secure configuration guidance often are not addressed at the 

same level of detail (or at all) in a single guidance document; however, both are required to 

secure a system against known attacks. This specification document proposes a data model and 

format specification for an extensible, interoperable checklist language that is capable of 

including both technical and non-technical requirements in the same XML document. 

1.2. Vision for Use 

XCCDF is designed to enable easier, more uniform creation of security checklists and procedural 

documents, and allow them to be used with a variety of commercial, Government off-the-shelf 

(GOTS), and open source tools. The motivation for this is improvement of security for IT 

systems, including the Internet, by better application of known security practices and 

configuration settings. 

One potential use for XCCDF is streamlining compliance to FISMA and Department of Defense 

(DOD) STIGs. Federal agencies, state and local governments, and the private sector have 

difficulty measuring the security of their IT systems. They also struggle to both implement 

technical policy (e.g., DISA STIGs, NIST SPs) and then to demonstrate unambiguously to 

various audiences (e.g., Inspector General, auditor) that they have complied and ultimately 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

improved the security of their systems. This difficulty arises from various causes, such as 

different interpretations of policy, system complexity, and human error. XCCDF proposes to 

automate certain technical aspects of security by converting English text contained in various 

publications (e.g., configuration guides, checklists, the National Vulnerability Database [NVD]) 

into a machine-readable XML format such that the various audiences (e.g., scanning vendors, 

checklist/configuration guide, auditors) will be operating in the same semantic context. The end 

result will allow organizations to use commercial off-the-shelf (COTS) tools to automatically 

check their security and map to technical compliance requirements. 

The scenarios below illustrate some uses of security checklists and tools that XCCDF will foster. 

Scenario 1 – 

An academic group produces a checklist for secure configuration of a particular server 

operating system version. A government organization issues a set of rules extending the 

academic checklist to meet more stringent user authorization criteria imposed by statute. 

A medical enterprise downloads both the academic checklist and the government 

extension, tailors the combination to fit their internal security policy, and applies an 

enterprise-wide audit using a commercial security audit tool. Reports output by the tool 

include remediation measures which the medical enterprise IT staff can use to bring their 

systems into full internal policy compliance. 

Scenario 2 – 

A federally-funded lab issues a security advisory about a new Internet worm. In addition 

to a prose description of the worm’s attack vector, the advisory includes a set of short 

checklists in a standard format that assess vulnerability to the worm for various operating 

system platforms. Organizations all over the world pick up the advisory, and use 

installed tools that support the standard format to check their status and fix vulnerable 

systems. 

Scenario 3 – 

An industry consortium, in conjunction with a product vendor, wants to produce a 

security checklist for a popular commercial server. The core security settings are the 

same for all OS platforms on which the server runs, but a few settings are OS-specific. 

The consortium crafts one checklist in a standard format for the core settings, and then 

writes several OS-specific ones that incorporate the core settings by reference. Users 

download the core checklist and the OS-specific extensions that apply to their 

installations, then run a checking tool to score their compliance with the checklist. 

1.3. Summary of Changes since Version 1.0 

XCCDF 1.0 received some review and critique after its release in January 2005. Most of the 

additions and changes in 1.1 come directly from suggestions by users and potential users. The 

list below describes the major changes; other differences are noted in the text. 

• Persistent/standard identifiers - To foster standardization and re-use of XCCDF rules, 

community members suggested that Rule objects bear long-term, globally unique 

identifiers. Support for identifiers, along with the scheme or organization that assigns 

them, is now part of the Rule object. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

• Versioning - To foster re-use of XCCDF rules, and to allow more precise tracking of 

Benchmark results over time, Benchmarks, Rules, and Profiles all support a version 

number. The version number also now supports a timestamp. 

• Severity - Rules can now support a severity level: info, low, medium, and high. 

Severity levels can be adjusted via Profiles. 

• Signatures – To foster sharing of XCCDF rules and groups of rules, each object that 

can be a standalone XCCDF document can have an XML digital signature: 

Benchmark, Group, Rule, Value, Profile, and TestResult. This allows any shared 

XCCDF object to have integrity and authenticity assurance. 

• Rule result enhancements – Recording Benchmark results has been improved in 

version 1.1: the ‘override’ property was added for rule-results in a TestResult object, 

several new Rule result status values have been added, and better instance detail 

support was added to rule-results for multiply-instantiated Rules. Also, the 

descriptions of the different Rule result status values and their role in scores have been 

clarified. 

• Enhancements for remediation - Several minor enhancements were made to the Rule’s 

properties for automated and interactive remediation (the Rule object's ‘fix’ and 

‘fixtext’ elements). 

• Interactive Value tailoring – To foster interactive tailoring by tools that can support it, 

the ‘interactive’ property was added to Value objects. It gives a Benchmark checking 

tool a hint that it should solicit a new value prior to each application of the 

Benchmark. Also, the ‘interfaceHint’ property was added, to allow a Benchmark 

author to suggest a UI model to the tool. 

• Scoring models – XCCDF 1.0 had only a single scoring model. 1.1 supports the 

notion of multiple scoring models, and two new models have been added to the 

specification. To support custom scoring models, the model and param properties 

have been added to the TestResult’s score element. 

• Re-usable plain text blocks – To foster re-use of common text with a Benchmark 

document, version 1.1 now supports definition of named, re-usable text blocks. 

• Richer XHTML references – Formatted text within XCCDF Benchmarks can now use 

XHTML object and anchor tags to reference other XCCDF objects within a generated 

document. 

• Target facts – It is important for a Benchmark test result to include extensive 

information from the system that was tested. To support this, the TestResult object 

now supports a list of target facts. Tools can use this list to store any relevant 

information they collect about the target platform or system. 

• Complex checks – The Rule object now supports a mechanism for using Boolean 

operators to compose complex checks from multiple individual checks. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

• Extension control – To give Benchmark authors more control over XCCDF 

inheritance, 1.1 supports the ‘override’ attribute on most property element children 

that can appear more than once in a Rule, Group, Value, or Profile. 

• Value acquisition support – The new ‘source’ property on the Value object allows a 

Benchmark author to suggest one or more possible ways to obtain correct or candidate 

values. The suggestions must be given as URIs. 

• Profile notes – To support better descriptions for Profiles, 1.1 supports a descriptive 

note facility for relating Rules and Profiles. 

• CPE – Applicability of XCCDF Rules and other objects to specific IT platforms may 

be specified using Common Platform Enumeration (CPE) identifiers. 

• Alternate check content – In 1.1.3, the semantics of checks permit multiple 

(alternative) references to checking engine content. 

• Multiple alternative requirements – In 1.1.3, the requires property of Items has been 

extended to allow specification of several alternative Items, any one of which satisfies 

the requirement. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

2. Requirements 

The general objective for XCCDF is to allow security analysts and IT experts to create effective 

and interoperable automated checklists, and to support the use of automated checklists with a 

wide variety of tools. Figure 1 shows some potential utilization scenarios. 

Figure 1 – Use Cases for XCCDF Documents 

Benchmark results

pdf

Security

Experts

and

Domain

Experts

Tailoring

Tools

Transform

Engine

Document

Generator

System

Administrator

or

Auditor

Compliance

Benchmarking

Tool

Other

Reporting

Tools

html

xsl

xml

xccdf

Security Status

Monitor or

Vulnerability Tester

System

Under

Test

Other

Tools

Benchmark Reports

Web pages

Publication

Documents

XCCDF

benchmark format

Non-compliance or

vulnerability

alerts

Formatting

information

Stylesheets

Fix scripts or updates

1

2

3

4

5

6

7

8

XML

XCCDF

XCCDF

XCCDF

XCCDF

System

tests

The following list describes some requirements for several of the use cases depicted in Figure 1: 

1. Security and domain experts create a security guidance document or checklist, which is 

an organized collection of rules about a particular kind of system or platform. To support 

this use, XCCDF must be an open, standardized format, amenable to generation by and 

editing with a variety of tools. It must be expressive enough to represent complex 

conditions and relationships about the systems to be assessed, and it must also 

incorporate descriptive material and remediative measures. (XCCDF Benchmarks may 

include specification of the hardware and/or software platforms to which they apply; 

however, it is recommended that programmatically ascertainable information should be 

relegated to the lower-level identification and remediation languages. For specifying 

programmatically ascertainable information in the XCCDF file, the specification should 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

be concrete and granular so that compliance checking tools can detect if a Rule is suited 

for a target platform.) 

2. Auditors and system administrators may employ tailoring tools to customize a security 

guidance document or checklist for their local environment or policies. For example, 

although NIST produces the technical security guidance for Windows XP Professional in 

the form of Special Publication 800-68, certain Federal agencies may have trouble 

applying all settings without exception. For those settings which hinder functionality 

(perhaps with Legacy systems, or in a hybrid Windows 2000/2003 domain), the agency 

may wish to tailor the XML received from the NIST Web site. For this reason, an 

XCCDF document must include the structure and interrogative text required to direct the 

user through the tailoring of a Benchmark, and it must be able to hold or incorporate the 

user’s tailoring responses. For example, a checklist user might want to set the password 

policy requirement to be more or less stringent than the provided security 

recommendations. XCCDF should be extensible to allow for the custom tailoring and 

inclusion of the explanatory text for deviation from recommended policy. 

3. Although the goal of XCCDF is to distill English (or other language) prose checklists into 

machine-readable XML, XCCDF should be structured to foster the generation of readable 

prose documents from XCCDF-format documents. 

4. The structure of an XCCDF document should support transformation into HTML, for 

posting the security guidance as a Web page. 

5. An XCCDF document should be transformable into other XML formats, to promote 

portability and interoperability. 

6. The primary use case for an XCCDF-formatted security guidance document is to 

facilitate the normalization of configuration content through automated security tools. 

Such tools should accept one or more XCCDF documents along with supporting system 

test definitions, and determine whether or not the specified rules are satisfied by a target 

system. The XCCDF document should support generation of a compliance report, 

including a weighted compliance score. 

7. In addition to a report, some tools may utilize XCCDF-formatted content (and associated 

content from other tools) to bring a system into compliance through the remediation of 

identified vulnerabilities or misconfigurations. XCCDF must be able to encapsulate the 

remediation scripts or texts, including several alternatives. 

8. XCCDF documents might also be used in vulnerability scanners, to test whether or not a 

target system is vulnerable to a particular kind of attack. For this purpose, the XCCDF 

document would play the role of a vulnerability alert, but with the ability to both describe 

the problem and drive the automated verification of its presence. 

In addition to these use cases, an XCCDF document should be amenable to embedding inside 

other documents. Likewise, XCCDF’s extensibility should include provisions for incorporating 

other data formats. And finally, XCCDF must be extensible to include new functionality, 

features, and data stores without hindering the functionality of existing XCCDF-capable tools. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

2.1. Structure and Tailoring Requirements 

The basic unit of structure for a security guidance document or checklist is a rule. A rule simply 

describes a state or condition which the target of the document should exhibit. A simple 

document might consist of a simple list of rules, but richer ones require additional structure. 

To support customization of the standardized XML format and subsequent generation of 

documents by and for consumers, XCCDF must allow authors to impose organization within the 

document. One such basic requirement is that authors will need to put related rules into named 

groups. 

An author must be able to designate the order in which rules or groups are processed. In the 

simplest case, rules and groups are processed in sequence according to their location in the 

XCCDF document. 

To facilitate customization, the author should include descriptive and interrogative text to help a 

user make tailoring decisions. The following two customization options are available: 

Selectability – A tailoring action might select or deselect a rule or group of rules for 

inclusion or exclusion from the security guidance document. For example, an entire 

group of rules that relate to physical security might not apply if one were conducting a 

network scan. In this case, the group of rules delineated under the physical security 

group could be deselected. In the case of NIST SP 800-53, certain rules apply according 

to the Impact Rating of the system. For this purpose, systems that have an Impact Rating 

of Low might not have all of the same access control requirements as a system with a 

High Impact Rating, and therefore the those rules that are not applicable for the Low

system can be deselected. 

Substitution – A tailoring action might substitute a locally-significant value for a general 

value in a rule. For example, at a site where all logs are sent to a designated logging host, 

the address of that log server might be substituted into a rule about audit configuration. 

Using the NIST SP 800-53 example, a system with an Impact Rating of High might 

require a 12-character password, whereas a system with an Impact Rating of Moderate

might only require an 8-character password. Depending on the Impact Rating of the 

target system, the user can customize or tailor the value through substitution. 

When customizing security guidance documents, the possibility arises that some rules within the 

same document might conflict or be mutually exclusive. To avert potential problems, the author 

of a security guidance document must be able to identify particular tailoring choices as 

incompatible, so that tailoring tools can take appropriate actions. 

In addition to specifying rules, XCCDF must support structures that foster use and re-use of 

rules. To this end, XCCDF must provide a means for related rules to be grouped and for sets of 

rules and groups to be designated, named, and easily applied. Examples of this requirement are 

demonstrated by DISA’s Gold and Platinum distinction with respect to STIG compliance (Gold 

being the less stringent of the two levels). NIST also provides distinctions according to 

environment and Impact Rating (High, Moderate, or Low) [12]. Likewise, the Center for 

Internet Security (CIS) designates multiple numeric levels for their checklists (e.g., Level 1, 

Level 2). 

To facilitate XCCDF adoption for the aforementioned requirements, XCCDF provides two basic 

processing modes: rule checking and document generation. It must be possible for a security 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

guidance or checklist author to designate the modes (e.g., Gold, Platinum, High Impact Rating, 

Level 1) under which a rule should be processed. 

2.2. Inheritance and Inclusion Requirements 

Some use cases require XCCDF to support mechanisms for authors to extend (inherit from) 

existing rules and rule groups, in addition to expressing rules and groups in their entirety. For 

example, it must be possible for one XCCDF document to include all or part of another as 

demonstrated in the following scenarios: 

• An organization might choose to define a foundational XCCDF document for a family of 

platforms (e.g., Unix-like operating systems) and then extend it for specific members of 

the family (e.g., Solaris) or for specific roles (e.g., mail server). 

• An analyst might choose to make an extended version of an XCCDF document by 

adding new rules and adjusting others. 

• If the sets of rules that constitute an XCCDF document come from several sources, it is 

useful to aggregate them using an inclusion mechanism. (Note: The XCCDF 

specification does not define its own mechanisms for inclusion; instead, implementations 

of XCCDF tools should support the XML Inclusion (XInclude) facility standardized by 

the World Wide Web Consortium [W3C] [10].) 

• Within an XCCDF document, it is desirable to share descriptive material among several 

rules, and to allow a specialized rule to be created by extending a base rule. 

• For updating an XCCDF document, it is convenient to incorporate changes or additions 

using extensions. 

• To allow broader site-specific or enterprise-specific customization, a user might wish to 

override or amend any portion of an XCCDF rule. 

2.3. Document and Report Formatting Requirements 

Generating English (or other language) prose documents from the underlying XCCDF 

constitutes a primary use case. Authors require mechanisms for formatting text, including 

images, and referencing other information resources. These mechanisms must be separable from 

the text itself, so each can be filtered out by applications that do not support or require them. 

(XCCDF 1.1 currently satisfies these formatting requirements mainly by allowing inclusion of 

Extensible Hypertext Markup Language [XHTML] markup tags [4].) 

The XCCDF language must also allow for the inclusion of content that does not contribute 

directly to the technical content. For example, authors tend to include ‘front matter’ such as an 

introduction, a rationale, warnings, and references. XCCDF allows for the inclusion of intradocument and external references and links. 

2.4. Rule Checking Requirements 

One of XCCDF’s main features is the organization and selection of target-applicable groups and 

rules for performing security and operational checks on systems. Therefore, XCCDF must have 

access to granular and expressive mechanisms for checking the state of a system according to the 

rule criteria. The model for this requirement includes the notion of collecting or acquiring the 

state of a target system, and then checking the state for conformance to conditions and criteria 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

expressed as rules. The operations used have varied with different existing applications; some 

rule checking systems use a database query operation model, others use a pattern-matching 

model, and still others load and store state in memory during execution. Rule checking 

mechanisms used for XCCDF must satisfy the following criteria: 

• The mechanism must be able to express both positive and negative criteria. A 

positive criterion means that if certain conditions are met, then the system satisfies the 

check, while a negative criterion means that if the conditions are met, the system fails the 

check. Experience has shown that both kinds are necessary when crafting criteria for 

checks. 

• The mechanism must be able to express Boolean combinations of criteria. It is often 

impossible to express a high-level security property as a single quantitative or qualitative 

statement about a system’s state. Therefore, the ability to combine statements with ‘and’ 

and ‘or’ is critical. 

• The mechanism must be able to incorporate tailoring values set by the user. As 

described above, substitution is important for XCCDF document tailoring. Any XCCDF 

checking mechanism must support substitution of tailored values into its criteria or 

statements as well as tailoring of the selected set of rules. 

A single rule specification scheme (e.g., Open Vulnerability and Assessment Language [OVAL] 

[15]) may not satisfy all potential uses of XCCDF. To facilitate other lower-level rule checking 

systems, XCCDF supports referencing by including the appropriate file and check reference in 

the XCCDF document. It is important that the rule checking system be defined separately from 

XCCDF itself, so that both XCCDF and the rule checking system can evolve and be used 

independently. This duality implies the need for a clear interface definition between XCCDF 

and the rule checking system, including the specification of how information should pass from 

XCCDF to the checking system and vice versa. 

2.5. Test Results Requirements 

Another objective of XCCDF is to facilitate a standardized reporting format for automated tools. 

In the case of many Federal agencies, several COTS and GOTS products are used to determine 

the security of IT systems and their compliance to various stated polices. Unfortunately, the 

outputs from these tools are not standardized and therefore costly customization can be required 

for trending, aggregation, and reporting. Addressing this use case, XCCDF provides a means for 

storing the results of the rule checking subsystem. 

Security tools sometimes include only the results of the test or tests in the form of a pass/fail 

status. Other tools provide additional information so that the user does not have to access the 

system to determine additional information (e.g., instead of simply indicating that more than one 

privileged account exists on a system, certain tools also provide the list of privileged accounts). 

Independent of the robust or minimal reporting of the checking subsystem, the following 

information is basic to all results: 

• The security guidance document or checklist used, along with any adaptations via 

customization or tailoring applied 

• Information about the target system to which the test was applied, including arbitrary 

identification and configuration information about the target system 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

• The time interval of the test, and the time instant at which each individual rule was 

evaluated 

• One or more compliance scores 

• References to lower-level details possibly stored in other output files. 

2.6. Metadata and Security Requirements 

As the recognized need for security increases, so does the number of recommended security 

configuration guidance documents. The DISA STIGs and accompanying checklist documents 

have been available under http://iase.disa.mil/stigs/checklist for many years. Likewise, NIST’s 

interactions with vendors and agencies have yielded checklist content provided at 

http://checklists.nist.gov/. NSA also maintain a web site for security guidance, at 

http://www.nsa.gov/snac/, and CIS provides checklist content at http://cisecurity.org/. 

Likewise, product vendors such as Microsoft Corporation, Sun Microsystems, and HewlettPackard (to name a few) are providing their own security guidance documents independent of 

traditional user guides. 

As of early 2007, the majority of these checklists exist in various repositories in English prose 

format; however, there is a recognized need and subsequent migration effort to represent said 

checklists in standardized XML format. To facilitate discovery and retrieval of security 

guidance documents in repositories and on the open Internet, XCCDF must support inclusion of 

metadata about a document. Some of the metadata that must be supported include: title, name of 

author(s), organization providing the guidance, version number, release date, update URL, and a 

description. Since a number of metadata standards already exist, it is preferable that XCCDF 

simply incorporate one or more of them rather than defining its own metadata model. 

In addition to specifying rules to which a target system should comply, an XCCDF document 

must support mechanisms for describing the steps to bring the target into compliance. While 

checking compliance to a given security baseline document is common, remediation of an IT 

system to the recommended security baseline document should be a carefully planned and 

implemented process. Security guidance users should be able to trust security guidance 

documents, especially if they intend to accept remediation advice from them. Therefore, 

XCCDF must support a mechanism whereby guidance users can validate the integrity, origin, 

and authenticity of guidance documents. 

Digital signatures are the natural mechanism to satisfy these integrity and proof-of-origin 

requirements. Fortunately, mature standards for digital signatures already exist that are suitable 

for asserting the authorship and protecting the integrity of guidance documents. XCCDF must 

provide a means to hold such signatures, and a uniform method for applying and validating them. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

3. Data Model 

The fundamental data model for XCCDF consists of four main object data types: 

1. Benchmark. An XCCDF document holds exactly one Benchmark object. A Benchmark 

holds descriptive text, and acts as a container for Items and other objects. 

2. Item. An Item is a named constituent of a Benchmark; it has properties for descriptive 

text, and can be referenced by an id. There are several derived classes of Items: 

• Group. This kind of Item can hold other Items. A Group may be selected or 

unselected. (If a Group is unselected, then all of the Items it contains are implicitly 

unselected.) 

• Rule. This kind of Item holds check references, a scoring weight, and may also hold 

remediation information. A Rule may be selected or unselected. 

• Value. This kind of Item is a named data value that can be substituted into other 

Items’ properties or into checks. It can have an associated data type and operator that 

expresses how the value should be used and how it can be tailored. 

3. Profile. A Profile is a collection of attributed references to Rule, Group, and Value 

objects. It supports the requirement to allow definition of named levels or baselines in a 

Benchmark (see Section 2.1). 

4. TestResult. A TestResult object holds the results of performing a compliance test 

against a single target device or system. 

Figure 2 shows the data model relationships as a Unified Modeling Language (UML) diagram. 

As shown in the figure, one Benchmark can hold many Items, but each Item belongs to exactly 

one Benchmark. Similarly, a Group can hold many Items, but an Item may belong to only one 

Group. Thus, the Items in an XCCDF document form a tree, where the root node is the 

Benchmark, interior nodes are Groups, and the leaves are Values and Rules. 

Figure 2 –XCCDF High-Level Data Model 

Item

Rule Value Group

Benchmark

Profile

* * *

* **

TestResult

*

* * *

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

A Profile object references Rule, Value, and Group objects. A TestResult object references Rule 

objects and may also reference a Profile object. 

The definition of a Value, Rule, or Group can extend another Value, Rule, or Group. The 

extending Item inherits property values from the extended Item. This extension mechanism is 

separate and independent of grouping. 

Group and Rule items can be marked by a Benchmark author as selected or unselected. A Group 

or Rule that is not selected does not undergo processing. The author may also stipulate, for a 

Group, Rule, or Value, whether or not the end user is permitted to tailor it. 

Rule items may have a scoring weight associated with them, which can be used by a Benchmark 

checking tool to compute a target system’s overall compliance score. Rule items may also hold 

remediation information. 

Value items include information about current, default, and permissible values for the Value. 

Each of these properties of a Value can have an associated selector id, which is used when 

customizing the Value as part of a Profile. For example, a Value might be used to hold a 

Benchmark’s lower limit for password length on some operating system. In a Profile for that 

operating system to be used in a closed lab, the default value might be 8, but in a Profile for that 

operating system to be used on the Internet, the default value might be 12. 

3.1. Benchmark Structure 

Typically, a Benchmark would hold one or more Groups, and each group would hold some 

Rules, Values, and additional child Groups. Figure 3 illustrates this relationship, and the order in 

which the contents of a Benchmark must appear. 

Figure 3 – Typical Structure of a Benchmark 

Benchmark

Group (d)

Value (b)

Group (e) Rule (h)

Rule (i)

Rule (f) Rule (g)

Profile Profile

Value (a) Value (c)

Group (j) Value (k) Rule (l) Rule (m)

Groups allow a Benchmark author to collect related Rules and Values into a common structure 

and provide descriptive text and references about them. Further, groups allow Benchmark users 

to select and deselect related Rules together, helping to ensure commonality among users of the 

same Benchmark. Lastly, groups affect Benchmark compliance scoring. As Section 3.3 

explains, an XCCDF compliance score is calculated for each group, based on the Rules and 

Groups in it. The overall XCCDF score for the Benchmark is computed only from the scores on 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

the immediate Group and Rule children of the Benchmark object. In the tiny Benchmark shown 

in Figure 3, the Benchmark score would be computed from the scores of Group (d) and Group 

(j). The score for Group (j) would be computed from Rule (l) and Rule (m). 

Inheritance 

The possible inheritance relations between Item object instances are constrained by the tree 

structure of the Benchmark, but are otherwise independent of it. In other words, all extension 

relationships must be resolved before the Benchmark can be used for compliance testing. An 

Item may only extend another Item of the same type that is ‘visible’ from its scope. In other 

words, an Item Y can extend a base Item X, as long as they are the same type, and one of the 

following visibility conditions holds: 

1. X is a direct child of the Benchmark. 

2. X is a direct child of a Group which is also an ancestor of Y. 

3. X is a direct child of a Group which is extended by any ancestor of Y. 

For example, in the tiny Benchmark structure shown in Figure 3, it would be legal for Rule (g) to 

extend Rule (f) or extend Rule (h). It would not be legal for Rule (i) to extend Rule (m), because 

(m) is not visible from the scope of (i). It would not be legal for Rule (l) to extend Group (g), 

because they are not of the same type. 

The ability for a Rule or Group to be extended by another gives Benchmark authors the ability to 

create variations or specialized versions of Items without making copies. 

3.2. Object Content Details 

The tables below show the properties that make up each data type in the XCCDF data model. 

Note that the properties that comprise a Benchmark or Item are an ordered sequence of property 

values, and the order in which they appear determines the order in which they are processed. 

Properties with a data type of “text” are string data that can include embedded formatting 

directives and hypertext links. Properties of type “string” may not include formatting. 

Properties of type “identifier” must be strings without spaces or formatting, obeying the 

definition of “NCName” from the XML Schema specification [2]. 

Note that, in this table, and in the similar tables throughout the section, a minimum value of 0 in 

the Count column indicates that the property is optional, and a minimum value of 1 or greater 

indicates that the property is mandatory. 

Benchmark 

Property Type Count Description 

id identifier 1 Benchmark identifier, mandatory 

title text 0-n Title of the XCCDF Benchmark document 

description text 0-n Text that describes the Benchmark 

version string+date 

+URI 

1 Version number of the Benchmark, with the 

date and time when the version was completed 

and an optional update URI 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Property Type Count Description 

status string+date 1-n Status of the Benchmark (see below) and date 

at which it attained that status (at least one 

status property must appear; if several appear, 

then the one with the latest date applies) 

resolved boolean 0-1 True if Benchmark has already undergone the 

resolution process (see Section 3.3) 

notice text 0-n Legal notices or copyright statements about 

this Benchmark; each notice has a unique 

identifier and text value 

front-matter text 0-n Text for the front of the Benchmark document 

rear-matter text 0-n Text for the back of the Benchmark document 

reference special 0-n A bibliographic reference for the Benchmark 

document: metadata or a simple string, plus an 

optional URL 

cpe-list special 0-1 A list of platform descriptions, in Common 

Platform Enumeration (CPE) format [16]

platform URI 0-n Target platforms for this Benchmark, each a 

URI referring to a platform listed in the 

community CPE dictionary or in the 

cpe-list property of this Benchmark 

plain-text string+ 

identifier 

0-n Reusable text blocks, each with a unique 

identifier; these can be included in other text 

blocks in the Benchmark 

model URI+ 

parameters 

0-n Suggested scoring model or models to be used 

when computing a compliance score for this 

Benchmark 

profiles Profile 0-n Profiles that reference and customize sets of 

Items in the Benchmark 

values Value 0-n Tailoring values that support Rules and 

descriptions in the Benchmark 

groups Group 0-n Groups that comprise the Benchmark; each 

group may contain additional Values, Groups, 

and Rules 

rules Rule 0-n Rules that comprise the Benchmark 

test-results TestResult 0-n Benchmark test result records (one per 

Benchmark run) 

metadata special 0-n Discovery metadata for the Benchmark 

signature special 0-1 A digital signature asserting authorship and 

allowing verification of the integrity of the 

Benchmark 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Conceptually, a Benchmark contains Group, Rule, and Value objects, and it may also contain 

Profile and TestResult objects. For ease of reading and simplicity of scoping, all Value objects 

must precede all Groups and Rules, which must precede all Profiles, which must precede all 

TestResults. These objects may be directly embedded in the Benchmark, or incorporated via 

W3C standard XML Inclusion [10]. 

Each status property consists of a status string and a date. Permissible string values are 

“accepted”, “draft”, “interim”, “incomplete”, and “deprecated”. Benchmark authors should mark 

their Benchmarks with a status to indicate a level of maturity or consensus. A Benchmark may 

contain one or more status properties, each holding a different status value and the data on which 

the Benchmark reached that status. 

The cpe-list property contains a listing of one or more platform names, with additional 

descriptive data, expressed in Common Platform Enumeration (CPE) format [16]. In CPE, a 

specific platform is identified by a unique URI. Each Rule, Group, Profile, Value, and the 

Benchmark itself may possess platform properties, each containing a CPE URI, that indicate the 

hardware/software platform to which the object applies. The Benchmark cpe-list property and 

platform properties are optional. Benchmark authors should use them to identify the systems or 

products to which their Benchmarks apply. 

Note that CPE URIs may be used in a Benchmark or other objects without defining them 

explicitly. CPE URIs that are described in the community dictionary should be used without 

re-definition. Authors can use the Benchmark cpe-list property to describe specific CPE URIs 

used in the Benchmark in more detail. 

The plain-text properties, new in XCCDF 1.1, allow commonly used text to be defined once and 

then re-used in multiple text blocks in the Benchmark. Note that each plain-text must have a 

unique id, and that the ids of other Items and plain-text properties must not collide. This 

restriction is imposed to permit easier implementation of document generation and reporting 

tools. 

Benchmark metadata allows authorship, publisher, support, and other information to be 

embedded in a Benchmark. Metadata should comply with existing commercial or government 

metadata specifications, to allow Benchmarks to be discovered and indexed. The XCCDF data 

model allows multiple metadata properties for a Benchmark; each property should provide 

metadata compliant with a different specification. The primary metadata format, which should 

appear in all published Benchmarks, is the simple Dublin Core Elements specification, as 

documented in [13]. 

Note that a digital signature, if any, applies only to the Object in which it appears, but after 

inclusion processing (note: it may be impractical to use inclusion and signatures together). Any 

digital signature format employed for XCCDF Benchmarks must be capable of identifying the 

signer, storing all information needed to verify the signature (usually, a certificate or certificate 

chain), and detecting any change to the content of the Benchmark. XCCDF tools that support 

signatures at all must support the W3C XML-Signature standard enveloped signatures [9]. 

Legal notice text is handled specially, as discussed in Section 3.3. 

Item (base) 

Property Type Count Description 

id identifier 1 Unique object identifier, mandatory 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Property Type Count Description 

title text 0-n Title of the Item (for human readers) 

description text 0-n Text that describes the Item 

warning text 0-n A cautionary note or caveat about the Item 

status string+date 0-n Status of the Item and date at which it attained 

that status, optional 

version string+date 

+URI 

0-1 Version number of the Benchmark, with the 

date and time when the version was completed 

and an optional update URI 

question string 0-n Interrogative text to present to the user during 

tailoring 

hidden boolean 0-1 If this Item should be excluded from any 

generated documents (default: false) 

prohibitChanges boolean 0-1 If tools should prohibit changes to this Item 

during tailoring (default: false) 

abstract boolean 0-1 If true, then this Item is abstract and exists only 

to be extended (default: false) 

cluster-id identifier 0-1 An identifier to be used from a Profile to refer 

to multiple Groups and Rules, optional 

reference special 0-n A reference to a document or resource where 

the user can learn more about the subject of this 

Item: content is Dublin Core metadata or a 

simple string, plus an optional URL 

signature special 0-1 Digital signature over this Item, optional 

Every Item may include one or more status properties. Each status property value represents a 

status that the Item has reached and the date at which it reached that status. Benchmark authors 

can use status elements to record the maturity or consensus level for Rules, Groups, and Values 

in the Benchmark. If an Item does not have an explicit status property value given, then its status 

is taken to be that of the Benchmark itself. The status property is not inherited. 

There are several Item properties that give the Benchmark author control over how Items may be 

tailored and presented in documents. The ‘hidden’ property simply prevents an Item from 

appearing in generated documents. For example, an author might set the hidden property on 

incomplete Items in a draft Benchmark. The ‘prohibitChanges’ property advises tailoring tools 

that the Benchmark author does not wish to allow end users to change anything about the Item. 

Lastly, a value of true for the ‘abstract’ property denotes an Item intended only for other Items to 

extend. In most cases, abstract Items should also be hidden. 

The ‘cluster-id’ property is optional, but it provides a means to identify related Value, Group and 

Rule items throughout the Benchmark. Cluster identifiers need not be unique: all the Items with 

the same cluster identifier belong to the same cluster. A selector in a Profile can refer to a 

cluster, thus making it easier for authors to create and maintain Profiles in a complex 

Benchmark. The cluster-id property is not inherited. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Group :: Item 

Property Type Count Description 

requires identifier 0-n The id of another Group or Rule in the 

Benchmark that must be selected for this 

Group to be applied and scored properly 

conflicts identifier 0-n The id of another Group or Rule in the 

Benchmark that must be unselected for this 

Group to be applied and scored properly 

selected boolean 1 If true, this Group is selected to be processed 

as part of the Benchmark when it is applied 

to a target system; an unselected Group is not 

processed, and none of its contents are 

processed either (i.e., all children of an 

unselected group are implicitly unselected). 

Default is true. Can be overridden by a 

Profile. 

rationale text 0-n Descriptive text giving rationale or 

motivations for abiding by this Group 

platform URI 0-n A platform to which this Group applies, a 

CPE platform URI. 

cluster-id identifier 0-1 An identifier to be used from Benchmark 

profiles to refer to multiple Groups and 

Rules, optional 

extends identifier 0-1 An id of a Group on which to base this 

Group, optional 

weight float 0-1 The relative scoring weight of this Group, for 

computing a compliance score; can be 

overridden by a Profile 

values Value 0-n Values that belong to this Group, optional 

groups Group 0-n Sub-groups under this Group, optional 

rules Rule 0-n Rules that belong to this Group, optional 

A Group can be based on (extend) another Group. The semantics of inheritance work differently 

for different properties, depending on their allowed count. For Items that belong to a Group, the 

extending Group includes all the Items of the extended Group, plus any defined inside the 

extending Group. For any property that is allowed to appear more than once, the extending 

Group gets the sequence of property values from the extended group, plus any of its own values 

for that property. For any property that is allowed to appear at most once, the extending Group 

gets its own value for the property if one appears, otherwise it gets the extended Group’s value of 

that property. Items that belong to an extended group are treated specially: the id property of any 

Item copied as part of an extended group must be replaced with a new, uniquely generated id. A 

Group for which the abstract property is true exists only to be extended by other Groups; it 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

should never appear in a generated document, and none of the Rules defined in it should be 

checked in a compliance test. Abstract Group objects are removed during resolution; for more 

information, see Section 3.3. 

To give the Benchmark author more control over inheritance for extending Groups (and other 

XCCDF objects), all textual properties that may appear more than once can bear an override 

attribute. For more information about inheritance overrides and extension, see Section 3.3. 

The requires and conflicts properties provide a means for Benchmark authors to express 

dependencies among Rules and Groups. Their exact meaning depends on what sort of 

processing the Benchmark is undergoing, but in general the following approach should be 

applied: if a Rule or Group is about to be processed, and any of the Rules or Groups identified in 

a requires property have a selected property value of false or any of the Items identified in a 

conflicts property have a selected property value of true, then processing for the Item should be 

skipped and its selected property should be set to false. 

The platform property of a Group indicates that the Group contains platform-specific Items that 

apply to some set of (usually related) platforms. First, if a Group does not possess any platform 

properties, then it applies to the same set of platforms as its enclosing Group or the Benchmark. 

Second, for tools that perform compliance checking on a platform, any Group whose set of 

platform property values do not include the platform on which the compliance check is being 

performed should be treated as if their selected property were set to false. Third, the platforms to 

which a Group apply should be a subset of the platforms applicable for the enclosing 

Benchmark. Last, if no platform properties appear anywhere on a Group or its enclosing Group 

or Benchmark, then the Group nominally applies to all platforms. 

The weight property denotes the importance of a Group relative to its sibling in the same Group 

or its siblings in the Benchmark (for a Rule that is a child of the Benchmark). Scoring is 

computed independently for each collection of sibling Groups and Rules, then normalized as part 

of the overall scoring process. For more information about scoring, see Section 3.3. 

Rule :: Item 

Property Type Count Description 

selected boolean 1 If true, this Rule is selected to be checked as 

part of the Benchmark when the Benchmark 

is applied to a target system; an unselected 

rule is not checked and does not contribute to 

scoring. Default is true. Can be overridden 

by a Profile. 

extends identifier 0-1 The id of a Rule on which to base this Rule 

(must match the id of another Rule) 

multiple boolean 0-1 Whether this rule should be multiply 

instantiated. If false, then Benchmark tools 

should avoid multiply instantiating this Rule. 

Default is false. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Property Type Count Description 

role string 0-1 Rule’s role in scoring and reporting; one of 

the following: “full”, “unscored”, 

“unchecked”. Default is “full”. Can be 

overridden by a Profile. 

severity string 0-1 Severity level code, to be used for metrics 

and tracking. One of the following: 

“unknown”, “info”, “low”, “medium”, 

“high”. Default is “unknown”. Can be 

overridden by a Profile. 

weight float 0-1 The relative scoring weight of this Rule, for 

computing a compliance score. Default is 

1.0. Can be overridden by a Profile. 

rationale text 0-n Some descriptive text giving rationale or 

motivations for complying with this Rule 

platform URI 0-n Platforms to which this Rule applies; a set of 

CPE URIs. 

requires identifier 0-n The id of another Group or Rule in the 

Benchmark that should be selected for this 

Rule to be applied and scored properly 

conflicts identifier 0-n The id of another Group or Rule in the 

Benchmark that should be unselected for this 

Rule to be applied and scored properly 

ident string+URI 0-n A long-term, globally meaningful name for 

this Rule. May be the name or identifier of a 

security configuration issue or vulnerability 

that the Rule remediates. Has an associated 

URI that denotes the organization or naming 

scheme which assigns the name.(see below). 

profile-note text + 

identifier 

0-n Descriptive text related to a particular 

Profile. This property allows a Benchmark 

author to describe special aspects of the Rule 

related to one or more Profiles. It has an id 

that can be specified as the ‘note-tag’ 

property of a Profile (see the Profile 

description, below). 

fixtext special 0-n Prose that describes how to fix the problem 

of non-compliance with this Rule; each 

fixtext property may be associated with one 

or more fix property values 

fix special 0-n A command string, script, or other system 

modification statement that, if executed on 

the target system, can bring it into full, or at 

least better, compliance with this Rule 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Property Type Count Description 

check special 0-n The definition of, or a reference to, the target 

system check needed to test compliance with 

this Rule. A check consists of three parts: 

the checking system specification on which it 

is based, a list of Value objects to export, and 

the content of the check itself. If a Rule has 

several check properties, each must employ a 

different checking system. 

complex-check special 0-1 A complex check is a boolean expression of 

other checks. At most one complex-check 

may appear in a Rule (see below). 

A Rule can be based on (extend) another Rule. This means that the extending Rule inherits all 

the properties of the extended or base Rule, some of which it might override with new values. 

For any property that is allowed to appear more than once, the extending Rule gets the sequence 

of property values from the extended group, plus any of its own values for that property. For any 

property that is allowed to appear at most once, the extending Rule gets its own value for the 

property if one appears, otherwise it gets the extended Rule’s value of that property. A Rule for 

which the abstract property is true should not be included in any generated document, nor should 

it be checked in any compliance test. Abstract Rules are removed during resolution (see Section 

3.3). 

The ‘multiple’ property provides direction about multiple instantiation to a processing tool 

applying the Rule. By setting ‘multiple’ to true, the Rule’s author is directing that separate 

components of the target to which the Rule can apply should be tested separately and the results 

recorded separately. By setting ‘multiple’ to false, the author is directing that the test results of 

such components be combined. If the processing tool cannot perform multiple instantiation, or if 

multiple instantiation of the Rule is not applicable for the target system, then processing tools 

may ignore this property. 

The ‘role’ property gives the Benchmark author additional control over Rule processing during 

application of a Benchmark. The default role (“full”) means that the Rule is checked, contributes 

to scoring according to the scoring model, and appears in any output reports. The “unscored” 

role means that the Rule is checked and appears in any output reports, but does not contribute to 

score computations. The “unchecked” role means that the Rule does not get checked, its Rule 

result status is set to unknown, and it does not contribute to scoring, but it can appear in output 

reports. The “unchecked” role is meant primarily for Rules that contain informational text, but 

for which no automated check is practical. 

The ‘weight’ property denotes the importance of a rule relative to its sibling in the same Group 

or its siblings in the Benchmark (for a Rule that is a child of the Benchmark). For more 

information about scoring, see Section 3.3. 

Each ‘ident’ property contains a globally meaningful name in some security domain; the string 

value of the property is the name, and a Uniform Resource Identifier (URI) designates the 

scheme or organization that assigned the name. By setting an ‘ident’ property on a Rule, the 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Benchmark author effectively declares that the Rule instantiates, implements, or remediates the 

issue for which the name was assigned. For example, the ident value might be a Common 

Vulnerabilities and Exposures (CVE) identifier; the Rule would be a check that the target 

platform was not subject to the vulnerability named by the CVE identifier, and the URI would be 

that of the CVE Web site. 

The ‘platform’ properties of a Rule indicate the platforms to which the Rule applies. Each 

platform property asserts a single CPE URI. If a Rule does not possess any platform properties, 

then it applies to the same set of platforms as its enclosing Group or Benchmark. For tools that 

perform compliance checking on a platform, if a Rule’s set of platform property values does not 

include the platform on which the compliance check is being performed, the Rule should be 

treated as if its selected property were set to false. Any platform property value that appears on a 

Rule should be a member of the set of platform property values of the enclosing Benchmark. 

Finally, if no platform properties appear anywhere on a Rule or its enclosing Group or 

Benchmark, then the Rule applies to all platforms. 

The check property consists of the following: a selector for use with Profiles, a URI that 

designates the checking system or engine, a set of export declarations, and the check content. 

The checking system URI tells a compliance checking tool what processing engine it must use to 

interpret or execute the check. The nominal or expected checking system is MITRE’s OVAL 

system (designated by http://oval.mitre.org/), but the XCCDF data model allows for 

alternative or additional checking systems. XCCDF also supports conveyance of tailoring values 

from the XCCDF processing environment down to the checking system, via export declarations. 

Each export declaration maps an XCCDF Value object id to an external name or id for use by the 

checking system. The check content is an expression or document in the language of the 

checking system; it may appear inside the XCCDF document (an enveloped check) or it may 

appear as a reference (a detached check). 

In place of a ‘check’ property, XCCDF 1.1 allows a ‘complex-check’ property. A complex 

check is a boolean expression whose individual terms are checks or complex-checks. This 

allows Benchmark authors to re-use checks in more flexible ways, and to mix checks written 

with different checking systems. A Rule may have at most one ‘complex-check’ property; on 

inheritance, the extending Rule’s complex-check replaces the extended Rule’s complex-check. 

If both check properties and a complex-check property appear in a Rule, then the check 

properties must be ignored. The following operators are allowed for combining the constituents 

of a complex-check: 

AND – if and only if all terms evaluate to Pass (true), then the complex-check evaluates 

to Pass. 

OR – if any term evaluates to Pass, then the complex-check evaluates to Pass. 

Truth-tables for the operators appear under their detailed descriptions in the next section. Note 

that each complex-check may also specify that the expression should be negated (boolean not). 

The properties ‘fixtext’ and ‘fix’ exist to allow a Benchmark author to specify a way to 

remediate non-compliance with a Rule. The ‘fixtext’ property provides a prose description of 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

the fix that needs to be made; in some cases this may be all that is possible to do in the 

Benchmark (e.g., if the fix requires manipulation of a GUI or installation of additional software). 

The ‘fix’ property provides a direct means of changing the system configuration to accomplish 

the necessary change (e.g., a sequence of command-line commands; a set of lines in a system 

scripting language like Bourne shell or in a system configuration language like Windows INF 

format; a list of update or patch ID numbers). 

The ‘fix’ and ‘fixtext’ properties are enhanced for XCCDF 1.1, to help tools support more 

sophisticated facilities for automated and interactive remediation of Benchmark findings. The 

following attributes can be associated with a fix or fixtext property value: 

• strategy – a keyword that denotes the method or approach for fixing the problem. This 

applies to both fix and fixtext. Permitted values: unknown (default), configure, 

combination, disable, enable, patch, policy, restrict, update. 

• disruption – an estimate for how much disruption the application of this fix will impose 

on the target. This applies to fix and fixtext. Permitted values: unknown, low, medium, 

high. 

• reboot – whether or not remediation will require a reboot or hard reset of the target. 

This applies to fix and fixtext. Permitted values: true (1) and false (0). 

• system – a URI representing the scheme, language, engine, or process for which the fix 

contents are written. XCCDF 1.1 will define several general-purpose URNs for this, but 

it is expected that tool vendors and system providers may need to define target-specific 

ones. This applies to fix only. 

• id/fixref – these attributes will allow fixtext properties to be associated with specific fix 

properties (pair up explanatory text with specific fix procedures). 

• platform – in case different fix scripts or procedures are required for different target 

platform types (e.g., different patches for Windows 2000 and Windows XP), this 

attribute allows a CPE platform URI to be associated with a fix property. 

For more information, consult the detailed definition of the fix and fixtext elements in Section 

4.2. 

Value :: Item 

Property Type Count Description 

value string + id 1-n The current value of this Value 

default string + id 0-n Default value of this Value object, optional 

type string 0-1 The data type of the Value: “string”, 

“number”, or “boolean” (default: “string”) 

extends identifier 0-1 The id of a Value on which to base this 

Value, optional 

operator string 0-1 The operator to be used for comparing this 

Value to some part of the test system’s 

configuration (see list below), optional 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Property Type Count Description 

lower-bound number + 

identifier 

0-n Minimum legal value for this Value 

(applies only if type is ‘number’) 

upper-bound number + 

identifier 

0-n Maximum legal value for this Value 

(applies only if type is ‘number’) 

choices list + id 0-n A list of legal or suggested values for this 

Value object, to be used during tailoring 

and document generation, optional 

match regular expr. 0-n A regular expression which the Value must 

match to be legal, optional 

(for more information, see [8]) 

interactive boolean 0-1 Tailoring for this Value should also be 

performed during Benchmark application, 

optional (default is false) 

interfaceHint string 0-1 User interface recommendation for 

tailoring, optional 

source URI 0-n URI indicating where the Benchmark tool 

may acquire a value for this Value object 

A Value is content that can be substituted into properties of other Items, including the interior of 

structured check specifications and fix scripts. A tool may choose any convenient form to store a 

Value’s value property, but the data type conveys how the value should be treated during 

Benchmark compliance testing. The data type property may also be used to give additional 

guidance to the user or to validate the user’s input. For example, if a Value object’s type 

property was “number”, then a tool might choose to reject user tailoring input that was not 

composed of digits. The default property holds a default value for the value property; tailoring 

tools may present the default value to users as a suggestion. 

A Value object may extend another Value object. In such cases, the extending object receives all 

the properties of the extended object, and may override them where needed. A Value object with 

the abstract property true should never be included in any generated document, and may not be 

exported to any compliance checking engine. 

When defining a Value object, the Benchmark author may specify the operator to be used for 

checking compliance with the value. For example, one part of an operating system (OS) 

Benchmark might be checking that the configuration included a minimum password length; the 

Value object that holds the tailorable minimum could have type “number” and operator “greater 

than”. Exactly how Values are used in rules may depend on the capabilities of the checking 

system. Tailoring tools and document generation tools may ignore the ‘operator’ property; 

therefore, Benchmark authors should included sufficient information in the description and 

question properties to make the role of the Value clear. The table below describes the operators 

permitted for each Value type. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Value Type Available Operators Remarks 

number equals, not equal, less than, greater than, 

less than or equal, greater than or equal 

Default operator: equals 

boolean equals, not equal Default operator: equals 

string equals, not equal, pattern match 

(pattern match means regular expression 

match; should comply with [8]) 

Default operator: equals 

A Value object includes several properties that constrain or limit the values that the Value may 

be given: value, default, match, choices, upper-bound, and lower-bound. Benchmark authors can 

use these Value properties to assist users in tailoring the Benchmark. These properties may 

appear more than once in a Value, and may be marked with a selector tag id. At most one 

instance of each may omit its selector tag. For more information about selector tags, see the 

description of the Profile object below. 

The upper-bound and lower-bound properties constrain the choices for Value items with a type 

property of ‘number’. For any other type, they are meaningless. The bounds they indicate are 

always inclusive. For example, if the lower-bound property for a Value is given as “3”, then 3 is 

a legal value. 

The ‘choices’ property holds a list of one or more particular values for the Value object; the 

‘choices’ property also bears a boolean flag, ‘mustMatch’, which indicates that the enumerated 

choices are the only legal ones (mustMatch=“1”) or that they are merely suggestions 

(mustMatch=“0”). The choices property should be used when there are a moderate number of 

known values that are most appropriate. For example, if the Value were the authentication mode 

for a server, the choices might be “password” and “pki”. 

The ‘match’ property provides a regular expression pattern that a tool may apply, during 

tailoring, to validate user input. The ‘match’ property applies only when the Value type is 

‘string’ or ‘number’. For example, if the Value type was ‘string’, but the value was meant to be 

a Cisco IOS router interface name, then the Value match property might be set to “[A-Za-z]+ 

*[0-9]+(/[0-9.]+)*”. This would allow a tailoring tool to reject an invalid user input like “f8xq+” 

but accept a legal one like “Ethernet1/3”. 

If a Value’s ‘prohibitChanges’ property is set to true, then it means that the Value’s value may 

not be changed by the user. This might be used by Benchmark authors in defining values that 

are integral to compliance, such as a timeout value, or it might be used by enterprise security 

officers in constraining a Benchmark to more tightly reflect organizational or site security 

policies. (In the latter case, a security officer could use the extension facility to make an 

untailorable version of a Value object, without rewriting it.) A Value object can have a ‘hidden’ 

property; if the hidden property is true, then the Value should not appear in a generated 

document, but its value may still be used. 

If the ‘interactive’ property is set, it is a hint to the Benchmark checking tool to ask the user for a 

new value for the Value at the beginning of each application of the Benchmark. The checking 

tool is free to ignore the property if asking the user is not feasible or not supported. Similarly, 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

the ‘interfaceHint’ property allows the Benchmark author to supply a hint to a benchmarking or 

tailoring tool about how the user might select or adjust the Value. The following strings are 

valid for the ‘interfaceHint’ property: “choice”, “textline”, “text”, “date”, and “datetime”. 

The ‘source’ property allows a Benchmark author to supply a URI, possibly tool-specific, that 

indicates where a benchmarking or tailoring tool may acquire values, value bounds, or value 

choices. 

Profile 

Property Type Count Description 

id identifier 1 Unique identifier for this Profile 

title string 1-n Title of the Item, for human readers 

description text 0-n Text that describes the Profile, optional 

extends identifier 0-1 The id of a Profile on which to base this 

Profile, optional 

abstract boolean 0-1 If true, then this Profile exists solely to be 

extended by other Profiles, and may not be 

applied to a Benchmark directly; 

optional (default: false) 

note-tag identifier 0-1 Tag identifier to match profile-note 

properties in Rules, optional 

status string + date 0-n Status of the Profile and date at which it 

attained that status, optional 

version string + date 0-1 Version of the Profile, with timestamp and 

update URI, optional 

prohibitChanges boolean 0-1 Whether or not tools should prohibit 

changes to this Profile (default: false) 

platform URI 0-n A target platform for this Profile, a CPE 

URI. Multiple platform URIs may be 

listed if the Profile applies to several 

platforms. 

reference string + URL 0-n A reference to a document or resource 

where the user can learn more about the 

subject of this Profile: a string and optional 

URL 

selectors special 0-n References to Groups, Rules, and Values, 

see below (references may be the unique id 

of an Item, or a cluster id) 

signature special 0-1 Digital signature over this Profile, optional 

A Profile object is a named tailoring of a Benchmark. While a Benchmark can be tailored in 

place, by setting properties of various objects, only Profiles allow one Benchmark document to 

hold several independent tailorings. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

A Profile can extend another Profile in the same Benchmark. The set of platform, reference, and 

selector properties of the extended Profile are prepended to the list of properties of the extending 

Profile. Inheritance of title, description, and reference properties are handled in the same way as 

for Item objects. 

The note-tag property is a simple identifier. It specifies which profile-note properties on Rules 

should be associated with this Profile. 

Benchmark authors can use the Profile’s ‘status’ property to record the maturity or consensus 

level of a Profile. If the status is not given explicitly in a Profile definition, then the Profile is 

taken to have the same status as its parent Benchmark. Note that status properties are not 

inherited. 

Each Profile contains a list of selectors which express a particular customization or tailoring of 

the Benchmark. There are four kinds of selectors: 

• select - a Rule/Group selector. This selector designates a Rule, Group, or cluster of 

Rules and Groups. It overrides the selected property on the designated Items. It 

provides a means for including or excluding rules from the Profile. 

• set-value – a Value selector. This selector overrides the value property of a Value 

object, without changing any of its other properties. It provides a means for directly 

specifying the value of a variable to be used in compliance checking or other 

Benchmark processing. This selector may also be applied to the Value items in a 

cluster, in which case it overrides the value properties of all of them. 

• refine-rule – a Rule/Group selector. This selector allows the Profile author to 

override the scoring weight, severity, and role of a Rule, Group, or cluster of Rules 

and Groups. Despite the name, this selector does apply for Groups, but only to their 

weight property. 

• refine-value – a Value selector. This selector designates the Value constraints to be 

applied during tailoring, for a Value object or the Value members of a cluster. It 

provides a means for authors to impose different constraints on tailoring for different 

profiles. (Constraints must be designated with a selector id. For example, a 

particular numeric Value might have several different sets of ‘upper-bound’ and 

‘lower-bound’ properties, designated with different selector ids. The refine-value 

selector tells benchmarking tools which set of bounds to enforce when that particular 

profile is in effect.) 

TestResult 

Property Type Count Description 

id identifier 1 Identifier for this TestResults object 

benchmark URI 0-1 Reference to Benchmark; mandatory if 

this TestResults object is in a file by 

itself, optional otherwise 

version string 0-1 The version number string copied from 

the Benchmark, optional 

title string 0-n Title of the test, for human readers 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Property Type Count Description 

remark string 0-n A remark about the test, possibly 

supplied by the person administering the 

Benchmark checking run, optional 

start-time timestamp 0-1 Time when test began, optional 

end-time timestamp 1 Time when test was completed and the 

results recorded, mandatory 

test-system string 0-1 Name of the test tool or program, 

optional 

target string 1-n Name of the target system whose test 

results are recorded in this object, 

mandatory 

target-address string 0-n Network address of the target 

target-facts special 0-1 A sequence of named facts about the 

target system or platform, including a 

type qualifier, optional 

platform URI 0-n The CPE platform URI indicating a 

platforms which the target system was 

found to meet. Tools may insert multiple 

platform URIs if the target system met 

multiple relevant platform definitions. 

profile identifier 0-1 The identifier of the Benchmark profile 

used for the test, if any 

set-value string + id 0-n Specific settings for Value objects used 

during the test, one for each Value 

rule-results special 1-n Outcomes of individual Rule tests, one 

per Rule instance 

score float + URI 1-n An overall score for this Benchmark test; 

at least one must appear 

signature special 0-1 Digital signature over this TestResult 

object, optional 

A TestResult object represents the results of a single application of the Benchmark to a single 

target platform. The properties of a TestResult object include test time, the identity and other 

facts about the system undergoing the test, and Benchmark information. If the test was 

conducted using a specific Profile of the Benchmark, then a reference to the Profile may be 

included. Also, multiple set-value properties may be included, giving the identifier and value for 

the Values that were used in the test. 

At least one ‘target’ property must appear in the TestResult object. Each appearance of the 

property supplies a name by which the target host or device was identified at the time the test 

was run. The name may be any string, but applications should include the fully qualified 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Domain Name System (DNS) name whenever possible. The ‘target-address’ property is 

optional; each appearance of the property supplies an address which was bound by the target at 

the time the test was run. Typical forms for the address include: Internet Protocol version 4 

(IPv4) address, Internet Protocol version 6 (IPv6) address, and Ethernet media access control 

(MAC) address. 

The ‘target-facts’ list is an optional part of the TestResult object. It contains a list of zero or 

more individual facts about the target system or platform. Each fact consists of the following: a 

name (URI), a type (“string”, “number”, or “boolean”), and the value of the fact itself. 

The main content of a TestResult object is a collection of rule-result records, each giving the 

result of a single instance of a rule application against the target. The TestResult must include 

one rule-result record for each Rule that was selected in the resolved Benchmark; it may also 

include rule-result records for Rules that were unselected in the Benchmark. A rule-result record 

contains the properties listed below. For more information about Benchmark application and 

scoring, see page 38. 

TestResult/rule-result 

Property Type Count Description 

rule-idref identifier 1 Identifier of a Benchmark Rule (from the 

Benchmark designated in the TestResult) 

time timestamp 0-1 Time when application of this instance of 

this Rule was completed, optional 

version string 0-1 The version number string copied from 

the version property of the Rule, optional 

severity string 0-1 The severity string code copied from the 

Rule; defaults to “unknown”, optional 

ident string + URI 0-n A globally meaningful name and URI for 

the issue or vulnerability, copied from 

the Rule 

result string 1 Result of this test: one of status values 

listed below 

override special 0-n An XML block explaining how and why 

an auditor chose to override the Rule’s 

result status, optional 

instance string 0-n Name of the target system component to 

which this result applies, for multiply 

instantiated Rules. May also include 

context and hierarchy information for 

nested contexts, optional (see below for 

details). 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Property Type Count Description 

message string + code 0-n Diagnostic messages from the checking 

engine, with optional severity (this would 

normally appear only for result values of 

“fail” or “error”) 

fix string 0-1 Fix script for this target platform, if 

available (would normally appear only 

for result values of “fail”) 

check special 0-n Encapsulated or referenced results to 

detailed testing output from the checking 

engine (if any); if multiple checks were 

executed as part of a complex-check, 

then data for each may appear here 

The result of a single test may be one of the following: 

pass – the target system or system component satisfied all the conditions of the Rule; a 

pass result contributes to the weighted score and maximum possible score. 

[Abbreviation: P] 

fail – the target system or system component did not satisfy all the conditions of the Rule; 

a fail result contributes to the maximum possible score. [Abbreviation: F] 

error – the checking engine encountered a system error and could not complete the test, 

therefore the status of the target’s compliance with the Rule is not certain. This could 

happen, for example, if a Benchmark testing tool were run with insufficient privileges. 

[Abbreviation: E] 

unknown – the testing tool encountered some problem and the result is unknown. For 

example, a result of ‘unknown’ might be given if the Benchmark testing tool were unable 

to interpret the output of the checking engine. [Abbreviation: U] 

notapplicable – the Rule was not applicable to the target of the test. For example, the 

Rule might have been specific to a different version of the target OS, or it might have 

been a test against a platform feature that was not installed. Results with this status do 

not contribute to the Benchmark score. [Abbreviation: N] 

notchecked – the Rule was not evaluated by the checking engine. This status is designed 

for Rules with a role of “unchecked”, and for Rules that have no check properties. It may 

also correspond to a status returned by a checking engine. Results with this status do not 

contribute to the Benchmark score. [Abbreviation: K] 

notselected – the Rule was not selected in the Benchmark. Results with this status do not 

contribute to the Benchmark score. [Abbreviation: S] 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

informational – the Rule was checked, but the output from the checking engine is simply 

information for auditor or administrator; it is not a compliance category. This status is 

the default for Rules with a role of “unscored”. This status value is designed for Rules 

whose main purpose is to extract information from the target rather than test compliance. 

Results with this status do not contribute to the Benchmark score. [Abbreviation: I] 

fixed – the Rule had failed, but was then fixed (possibly by a tool that can automatically 

apply remediation, or possibly by the human auditor). Results with this status should be 

scored the same as pass. [Abbreviation: X] 

The ‘instance’ property specifies the name of a target subsystem or component that passed or 

failed a Rule. This is important for Rules that apply to components of the target system, 

especially when a target might have several such components. For example, a Rule might 

specify a particular setting that needs to be applied on every interface of a firewall; for 

Benchmark compliance results, a firewall target with three interfaces would have three ruleresult elements with the same rule id, each with an independent value for the ‘result’ property. 

For more discussion of multiply instantiated Rules, see page 40. 

The ‘check’ property consists of the URI that designates the checking system, and detailed 

output data from the checking engine. The detailed output data can take the form of 

encapsulated XML or text data, or it can be a reference to an external URI. (Note: this is 

analogous to the form of the Rule object’s check property, used for referring to checking engine 

input.) 

The override property provides a mechanism for an auditor to change the Rule result assigned by 

the Benchmark checking tool. This is necessary (a) when checking a rule requires reviewing 

manual procedures or other non-IT conditions, and (b) when a Benchmark check gives an 

inaccurate result on a particular target system. The override element contains the following 

properties: 

Property Type Count Description 

time timestamp 1 When the override was applied 

authority string 1 Name or other identification for the 

human principal authorizing the override 

old-result string 1 The rule result status before this override 

new-result string 1 The new, override rule result status 

remark string 1 Rationale or explanation text for why or 

how the override was applied 

XCCDF is not intended to be a database format for detailed results; the TestResult object offers a 

way to store the results of individual tests in modest detail, with the ability to reference lowerlevel testing data. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

3.3. Processing Models 

The XCCDF specification is designed to support automated XCCDF document processing by a 

variety of tools. There are five basic types of processing that a tool might apply to an XCCDF 

document: 

1. Tailoring. This type of processing involves loading an XCCDF document, allowing a 

user to set the value property of Value items and the selected property of all Items, and 

then generating a tailored XCCDF output document. 

2. Document Generation. This type of processing involves loading an XCCDF document 

and generating textual or formatted output, usually in a form suitable for printing or 

human perusal. 

3. Transformation. This is the most open-ended of the processing types: it involves 

transforming an XCCDF document into a document in some other representation. 

Typically, a transformation process will involve some kind of stylesheet or specification 

that directs the transformation (e.g., an Extensible Stylesheet Language Transformation 

[XSLT] stylesheet). This kind of processing can be used in a variety of contexts, 

including document generation. 

4. Compliance Checking. This is the primary form of processing for XCCDF documents. 

It involves loading an XCCDF document, checking target systems or data sets that 

represent the target systems, computing one or more scores, and generating one or more 

XCCDF TestResult objects. Some tools might also generate other outputs or store 

compliance information in some kind of database. 

5. Test Report Generation. This form of processing can be performed only on an XCCDF 

document that includes one or more TestResult objects. It involves loading the 

document, traversing the list of TestResult objects, and generating non-XCCDF output 

and/or human-readable reports about selected ones. 

Tailoring, document generation, and compliance checking all share a similar processing model 

consisting of two steps: loading and traversal. The processing sequence required for loading is 

described in the subsection below. Note that loading must be complete before traversal begins. 

When loading is complete, a Benchmark is said to be resolved. 

Loading Processing Sequence 

Before any loading begins, a tool should initialize an empty set of legal notices and an empty 

dictionary of object ids. 

Sub-Step Description 

Loading.Import Import the XCCDF document into the program and build an initial 

internal representation of the Benchmark object, Groups, Rules, and 

other objects. If the file cannot be read or parsed, then Loading fails. 

(At the beginning of this step, any inclusion processing specified 

with XInclude elements should be performed. The resulting XML 

information set should be validated against the XCCDF schema 

given in Appendix A.) Go to the next step: Loading.Noticing. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Sub-Step Description 

Loading.Noticing For each notice property of the Benchmark object, add the notice to 

the tool’s set of legal notices. If a notice with an identical id value is 

already a member of the set, then replace it. If the Benchmark’s 

resolved property is set, then Loading succeeds, otherwise go to the 

next step: Loading.Resolve.Items. 

Loading.Resolve.Items For each Item in the Benchmark that has an extends property, resolve 

it by using the following steps: (1) if the Item is Group, resolve all 

the enclosed Items, (2) resolve the extended Item, (3) prepend the 

property sequence from the extended Item to the extending Item, 

(4) if the Item is a Group, assign values for the id properties of Items 

copied from the extended Group, (5) remove duplicate properties and 

apply property overrides, and (6) remove the extends property. If 

any Item’s extends property identifier does not match the identifier 

of a visible Item of the same type, then Loading fails. If the directed 

graph formed by the extends properties includes a loop, then Loading 

fails. Otherwise, go to the next step: Loading.Resolve.Profiles. 

Loading.Resolve.Profiles For each Profile in the Benchmark that has an extends property, 

resolve the set of properties in the extending Profile by applying the 

following steps: (1) resolve the extended Profile, (2) prepend the 

property sequence from the extended Profile to that of the extending 

Profile, (3) remove all but the last instance of duplicate properties. If 

any Profile’s extends property identifier does not match the identifier 

of another Profile in the Benchmark, then Loading fails. 

If the directed graph formed by the extends properties of Profiles 

includes a loop, then Loading fails. Otherwise, go to 

Loading.Resolve.Abstract. 

Loading.Resolve.Abstract For each Item in the Benchmark for which the abstract property is 

true, remove the Item. For each Profile in the Benchmark for which 

the abstract property is true, remove the Profile. Go to the next step: 

Loading.Resolve.Finalize. 

Loading.Resolve.Finalize Set the Benchmark resolved property to true; Loading succeeds. 

If the Loading step succeeds for an XCCDF document, then the internal data model should be 

complete, and every Item should contain all of its own content. An XCCDF file that has no 

extends properties is called a resolved document. Only resolved XCCDF documents should be 

subjected to Transformation processing. 

XML Inclusion processing must happen before any validation or processing. Typically, it will 

be performed by the XML parser as the XML file is processed at the beginning of 

Loading.Import. XML Inclusion processing is independent of all XCCDF processing. 

During the Loading.Resolve.Items and Loading.Resolve.Profiles steps, the processor must flatten 

inheritance relationships. The conceptual model for XCCDF object properties is a list of namevalue pairs; property values defined in an extending object are appended to the list inherited from 

the extending object. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

There are five different inheritance processing models for Item and Profile properties. 

• None – the property value or values are not inherited. 

• Prepend – the property values are inherited from the extended object, but values on 

the extending object come first, and inherited values follow. 

• Append – the property values are inherited from the extended object; additional 

values may be defined on the extending object. 

• Replace – the property value is inherited; a property value explicitly defined on the 

extending object replaces an inherited value. 

• Override – the property values are inherited from the extended object; additional 

values may be defined on the extending object. An additional value can override 

(replace) an inherited value, if explicitly tagged as ‘override’. 

The table below shows the inheritance processing model for each of the properties supported on 

Group, Rule, Value, and Profile objects. 

Processing Model Properties Remarks 

None abstract, cluster-id, extends, 

id, signature, status 

These properties cannot be 

inherited at all; they must 

be given explicitly 

Prepend source, choices 

Append requires, conflicts, ident, 

fix, value, default, choices, 

operator, lower-bound, 

upper-bound, match, select, 

note-tag, refine-value, 

refine-rule, set-value 

Additional rules may apply 

during Benchmark 

processing, tailoring, or 

report generation 

Replace hidden, prohibitChanges, 

selected, version, weight, 

operator, interfaceHint, 

check, complex-check, role, 

severity, type, interactive, 

multiple 

For the check property, 

checks from different 

systems are considered 

different properties 

Override title, description, platform, 

question, rationale, warning, 

reference, fixtext, 

profileNote 

For properties that have a 

locale (xml:lang specified), 

values with different 

locales are considered to be 

different properties 

Every resolved document must satisfy the condition that every id attribute is unique. Therefore, 

it is very important that the Loading.Resolution step generate a fresh unique id for any Group, 

Rule, or Value object that gets created through extension of its enclosing Group. One way to do 

this would be to generate and assign a random unique id during sub-step (4) of 

Loading.Resolve.Items. Also note that it is necessary to assign an extends property to the newly 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

created Items, based on the id or extends property of the Item that was copied (if the Item being 

copied has an extends property, then the new Item gets the same value for the extends property, 

otherwise the new Item gets the id value of the Item being copied as its extends property). 

The second step of processing is Traversal. The concept behind Traversal is basically a preorder, depth-first walk through all the Items that make up a Benchmark. However, Traversal 

works slightly differently for each of the three kinds of processing, as described further below. 

Benchmark Processing Algorithm 

The id of a Profile may be specified as input for Benchmark processing. 

Sub-Step Description 

Benchmark.Front Process the properties of the Benchmark object 

Benchmark.Profile If a Profile id was specified, then apply the settings in the Profile to the 

Items of the Benchmark 

Benchmark.Content For each Item in the Benchmark object’s items property, initiate 

Item.Process 

Benchmark.Back Perform any additional processing of the Benchmark object properties 

The sub-steps Front and Back will be different for each kind of processing, and each tool may 

perform specialized handling of Benchmark properties. For document generation, Profiles may 

be processed separately as part of Benchmark.Back, to generate part of the output document. 

Item Processing Algorithm 

Sub-Step Description 

Item.Process Check the contents of the requires and conflicts properties, and if any 

required Items are unselected or any conflicting Items are selected, then 

set the selected and allowChanges properties to false. 

Item.Select If any of the following conditions holds, cease processing of this Item. 

1. The processing type is Tailoring, and the optional property and 

selected property are both false. 

2. The processing type is Document Generation, and the hidden 

property is true. 

3. The processing type is Compliance Checking, and the selected 

property is false. 

4. The processing type is Compliance Checking, and the current 

platform (if known by the tool) is not a member of the set of platforms 

for this Item. 

Group.Front If the Item is a Group, then process the properties of the Group. 

Group.Content If the Item is a Group, then for each Item in the Group’s items property, 

initiate Item.Process. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Sub-Step Description 

Rule.Content If the Item is a Rule, then process the properties of the Rule. 

Value.Content If the Item is a Value, then process the properties of the Value. 

Processing the properties of an Item is the core of Benchmark processing. The list below 

describes some of the processing in more detail. 

• For Tailoring, the key to processing is to query the user and incorporate the user’s 

response into the data. For a Group or Rule, the user should be given a yes/no choice 

if the optional property is true. For a Value item, the user should be given a chance 

to supply a string value, possibly validated using the type property. The output of a 

tailoring tool will usually be another XCCDF file. 

• For Document Generation, the key to processing is to generate an output stream that 

can be formatted as a readable or printable document. The exact formatting 

discipline will depend on the tool and the target output format. In general, the 

selected and optional properties are not germane to Document Generation. The 

platform properties may be used during Document Generation for generation of 

platform-specific versions of a document. 

• For Compliance Checking, the key to processing is applying the Rule checks to the 

target system or collecting data about the target system. Tools will vary in how they 

do this and in how they generate output reports. It is also possible that some Rule 

checks will need to be applied to multiple contexts or features of the target system, 

generating multiple pass or fail results for a single Rule object. 

Note that it is possible (but inadvisable) for a Benchmark author to set up circular dependencies 

or conflicts using the requires and conflicts properties. To prevent ambiguity, tools must process 

the Items of the Benchmark in order, and must not change the selected property of any Rule or 

Group more than once during a processing session. 

Substitution Processing 

XCCDF supports the notion of named parameters, Value objects, which can be set by a user 

during the tailoring process, and then substituted into content specified elsewhere in the 

Benchmark. XCCDF 1.1 also supports the notion of plain-text definitions in a Benchmark; these 

are re-usable chunks of text that may be substituted into other texts using the substitution 

facilities described here. 

As described in the next section, a substitution is always indicated by a reference to the id of a 

particular Value object, plain-text definition, or other Item in the Benchmark. 

During Tailoring and Document Generation, a tool should substitute the title property of the 

Value object for the reference in any text shown to the user or included in the document. At the 

tool author’s discretion, the title may be followed by the Value object’s value property, suitably 

demarcated. For plain-text definitions, any reference to the definition should be replaced by the 

string content of the definition. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Any appearance of the instance element in the content of a fix element should be replaced by a 

locale-appropriate string to represent a target system instance name. 

During Compliance Checking, Value objects designated for export to the checking system are 

passed to it. In general, the interface between the XCCDF checking tool and the underlying 

checking system or engine must support passing the following properties of the Value: value, 

type, and operator. 

During creation of TestResult objects on conclusion of Compliance Checking, any fix elements 

present in applied Rules, and matching the platform to which the compliance test was applied, 

should be subjected to substitution and the resulting string used as the value of the fix element 

for the rule-result element. Each sub element should be replaced by the value of the referenced 

Value object or plain-text definition actually used during the test. Each instance element should 

be replaced by the value of the rule-result instance element. 

Rule Application and Compliance Scoring 

When a Benchmark compliance checking tool performs a compliance run against a system, it 

accepts as inputs the state of the system and a Benchmark, and produces some outputs, as shown 

below. 

Figure 4 – Workflow for Checking Benchmark Compliance 

Benchmark Reports

Fix scripts or updates

Benchmark results

Benchmark

Compliance

Checking Tool

xml

System

Under

Test

XCCDF

state

rules

• Benchmark Report – A human-readable report about compliance, including the 

compliance score, and a listing of which rules passed and which failed on the system. 

If a given rule applies to multiple parts or components of the system, then multiple 

pass/fail entries may appear on this list; multiply-instantiated rules are discussed in 

more detail below. The report may also include recommended steps for improving 

compliance. The format of the benchmark report is not specified here, but might be 

some form of formatted or rich text (e.g., HTML). 

• Benchmark results – A machine-readable file about compliance, meant for storage, 

long-term tracking, or incorporation into other reports (e.g., a site-wide compliance 

report). This file may be in XCCDF, using the TestResult object, or it may be in 

some tool-specific data format. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

• Fix scripts – Machine-readable files, usually text, the application of which will 

remediate some or all of the non-compliance issues found by the tool. These scripts 

may be included in XCCDF TestResult objects. 

Scoring and Results Model 

Semantically, the output or result of a single Benchmark compliance test consists of four parts: 

1. Rule result list – a vector V of result elements e, with each element a 6-tuple 

e={r, p, I, t, F,O} where: 

• r is the Rule id 

• p is the test result, one of {pass, fail, error, unknown, notapplicable, notchecked, 

notselected, informational, fixed}. A test whose result p is ‘error’ or ‘unknown’ is 

treated as ‘fail’ for the purposes of scoring; tool developers may wish to alert the 

user to erroneous and unknown test results. A test whose result p is one of 

{notapplicable, notchecked, informational, notselected} does not contribute to 

scoring in any way. A test whose result p is ‘fixed’ is treated as a pass for score 

computation. 

• I is the instance set, identifying the system components, files, interfaces, or 

subsystems to which the Rule was applied. Each element of I is a triple {n,c,p}, 

where n is the instance name, c is the optional instance context, and p is the optional 

parent context. The context c, when present, describes the scope or significance of 

the name n. The parent context p allows the members of I to express nested 

structure. I must be an empty set for tests that are not the result of multiply 

instantiated Rules (see below). 

• t is the time at which the result of the Rule application was decided. 

• F is the set of fixes, from the Rule’s fix properties, that should bring the target 

system into compliance (or at least closer to compliance) with the rule. F may be 

null if the Rule did not possess any applicable fix properties, and must be null when 

p is equal to pass. Each fix f in F consists of all the properties defined in the 

description of the Rule fix property: content, strategy, disruption, reboot, system, id, 

and platform. 

• O is the set of overrides, each o in O consisting of the five properties listed for the 

rule-result override property: time, authority, old-result, new-result, and remark. 

Overrides do not affect score computation. 

2. Scores – a vector S, consisting of one or more score values s, with each s a pair consisting 

of a real number and a scoring model identifier. 

3. Identification – a vector of strings which identify the Benchmark, Profile (if any), and 

target system to which the Benchmark was applied. 

4. Timestamps – two timestamps recording the beginning and the end of the interval when 

the Benchmark was applied and the results compiled. 

Each element of the pass/fail list V conveys the compliance of the system under test, or one 

component of it, with one Rule of the Benchmark. Each Rule has a weight, title, and other 

attributes as described above. Each element of V may include an instance name, which gives the 

name of a system component to which the pass or fail designation applies. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

XCCDF 1.1 defines a default scoring model and two optional scoring models, and also permits 

Benchmark checking tools to support additional proprietary or consensus models. A Benchmark 

may specify the scoring model to be used. In the absence of an explicit scoring model specified 

in the Benchmark, compliance checking tools must compute a score based on the default 

XCCDF model, and may compute additional scoring values based on other models. The default 

model computes a score based on relative weights of sibling rules, as described in the next subsection. 

The fix scripts are collected from the fix properties of the rules in elements of V where p is False. 

A compliance checking or remediation tool may choose to concatenate, consolidate, and/or 

deconflict the fix scripts; mechanisms for doing so are outside the scope of this specification. In 

the simplest cases, tools must perform Value substitution on each rule’s fix property before 

making it part of the output results. 

Score Computation Algorithms 

This sub-section describes the XCCDF default scoring model, which compliance checking tools 

must support, and two additional models that tools may support. Each scoring model is 

identified by a URI. When a Benchmark compliance test is performed, the tool performing the 

Benchmark may use any score computation model designated by the user. The Benchmark 

author can suggest or recommend scoring models by indicating them in the Benchmark object 

using the “model” property. The default model is indicated implicitly for all Benchmarks. 

The Default Model 

This model is identified by the URI “urn:xccdf:scoring:default”. It was the only model 

supported in XCCDF 1.0, and remains the default for compatibility. 

In the default model, computation of the XCCDF score proceeds independently for each 

collection of siblings in each Group, and then for the siblings within the Benchmark. This 

relative-to-siblings weighted scoring model is designed for flexibility and to foster independent 

authorship of collections of Rules. Benchmark authors must keep the model in mind when 

assigning weights to Groups and Rules. For a very simple Benchmark consisting only of Rules 

and no Groups, weights may be omitted. 

The objects of an XCCDF Benchmark form the nodes of a tree. The default model score 

computation algorithm simply computes a normalized weighted sum at each tree node, omitting 

Rules and Groups that are not selected, and Groups that have no selected Rules under them. The 

algorithm at each selected node is: 

Sub-Step Description 

Score.Rule If the node is a Rule, then assign a count of 1, and if the test result is 

‘pass’, assign the node a score of 100, otherwise assign a score of 0. 

Score.Group.Init If the node is a Group or the Benchmark, assign a count of 0, a score s 

of 0.0, and an accumulator a of 0.0. 

Score.Group.Recurse For each selected child of this Group or Benchmark, do the following: 

(1) compute the count and weighted score for the child using this 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Sub-Step Description 

algorithm, (2) if the child’s count value is not 0, then add the child’s 

weighted score to this node’s score s, add 1 to this node’s count, and 

add the child’s weight value to the accumulator a. 

Score.Group.Normalize Normalize this node’s score: compute s = s / a.

Score.Weight Assign the node a weighted score equal to the product of its score and 

its weight. 

The final test score is the normalized score value on the root node of the tree, which is the 

Benchmark object. 

The Flat Model 

This model is identified by the URI “urn:xccdf:scoring:flat”. 

Under this model, the set of Rule results is treated as a vector V, as described above. The 

following algorithm is used to compute the score. 

Sub-Step Description 

Score.Init Initialize both the score s and the maximum score m to 0.0. 

Score.Rules For each element e in V where e.p is not equal to ‘notapplicable’: 

 - add the weight of rule e.r to m

 - if the value e.p equals ‘pass’ or ‘fixed’, add the weight of 

 the rule e.r to s. 

Thus, the flat model simply computes the sum of the weights for the Rules that passed as the 

score, and the sum of the weights of all the applicable Rules as the maximum possible score. 

This model is simple and easy to compute, but scores between different target systems may not 

be directly comparable because the maximum score can vary. 

The Flat Unweighted Model 

This model is identified by the URI “urn:xccdf:scoring:flat-unweighted”. It is computed in 

exactly the same way as the flat model, except that all weights are taken to be 1.0. 

Multiply-Instantiated Rules 

A security auditor applying a security guidance document to a system typically wants to know 

two things: how well does the system comply, and how can non-compliant items be reconciled 

(either fixed or determined not to be salient)? 

Many XCCDF documents include Rules that apply to system components. For example, a host 

OS Benchmark would probably contain Rules that apply to all users, and a router Benchmark 

will contain Rules that apply to all network interfaces. When the system holds many of such 

components, it is not adequate for a tool to inform the administrator or auditor that a Rule failed; 

it should report exactly which components failed the Rule. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

A processing engine that performs a Benchmark compliance test may deliver zero or more 

pass/fail triples, as described above. In the most common case, each compliance test Rule will 

yield one result element. In a case where a Rule was applied multiple times to multiple 

components of the system under test, a single Rule could yield multiple result elements. If each 

of multiple relevant components passes the Rule, the processing engine may deliver a single 

result element with an instance set I=null. For the purposes of scoring, a Rule contributes to the 

positive score only if all instances of that Rule have a test result of ‘pass’. If any component of 

the target system fails a Rule, then the entire Rule is considered to have failed. This is 

sometimes called “strict scoring”. 

 41 
SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

4. XML Representation 

This section defines a concrete representation of the XCCDF data model in XML, using both 

core XML syntax and XML Namespaces. 

4.1. XML Document General Considerations 

The basic document format consists of a root “Benchmark” element, representing a Benchmark 

object. Its child elements are the contents of the Benchmark object, as described in Section 3.2. 

All the XCCDF elements in the document will belong to the XCCDF namespace, including the 

root element. The namespace URI corresponding to this version of the specification is 

“http://checklists.nist.gov/xccdf/1.1”. The namespace of the root Benchmark element serves to 

identify the XCCDF version for a document. Applications that process XCCDF can use the 

namespace URI to decide whether or not they can process a given document. If a namespace 

prefix is used, the suggested prefix string is “cdf”. 

XCCDF attributes are not namespace qualified. All attributes begin with a lowercase letter, 

except the “Id” attribute (for compatibility with XML Digital Signatures [9]). 

The example below illustrates the outermost structure of an XCCDF XML document. 

Example 1 – Top-Level XCCDF XML 

<?xml version="1.0" ?> 

<cdf:Benchmark id="example1" xml:lang="en" Id="toSign" 

 xmlns:htm="http://www.w3.org/1999/xhtml" 

 xmlns:cdf="http://checklists.nist.gov/xccdf/1.1" 

 xmlns:cdfp="http://www.cisecurity.org/xccdf/platform/0.2.3"/> 

 <cdf:status date="2004-10-12">draft</cdf:status> 

 <cdf:title>Example Benchmark File</cdf:title> 

 <cdf:description> 

 A <htm:b>Small</htm:b> Example 

 </cdf:description> 

 <cdf:version>0.2</cdf:version> 

 <cdf:reference href="http://www.ietf.org/rfc/"> 

 Internet RFCs 

 </cdf:reference> 

</cdf:Benchmark> 

Validation is strongly suggested but not required for tools that process XCCDF documents. The 

XML Schema attribute ‘schemaLocation’ may be used to refer to the XCCDF Schema (see 

Appendix A). 

Properties of XCCDF objects marked as type ‘text’ in Section 3.2 may contain embedded 

formatting, presentation, and hyperlink structure. XHTML Basic tags must be used to express 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

the formatting, presentation, and hyperlink structure within XCCDF documents. In particular, 

the core modules noted in the XHMTL Basic Recommendation [4] are permitted in XCCDF 

documents, plus the Image module and the Presentation module. How an XCCDF processing 

tool handles embedded XHTML content in XCCDF text properties is implementation-dependent, 

but at the least every tool must be able to process XCCDF files even when embedded XHTML 

elements are present. Tools that perform document generation processing should attempt to 

preserve the formatting semantics implied by the Text and List modules, support the link 

semantics implied by the Hypertext module, and incorporate the images referenced via the Image 

module. 

4.2. XML Element Dictionary 

This subsection describes each of the elements and attributes of the XCCDF XML specification. 

Each description includes the parent elements feasible for that element, as well as the child 

elements it might normally contain. Most elements are in the XCCDF namespace, which for 

version 1.1 is “http://checklists.nist.gov/xccdf/1.1”. The full schema appears in Appendix A. 

Many of the elements listed below are described as containing formatted text (type ‘text’ in 

Section 3.2). These elements may contain Value substitutions, and formatting expressed as 

described in Section 4.3. 

XML is case-sensitive. The XML syntax for XCCDF follows a common convention for 

representing object-oriented data models in XML: elements that correspond directly to object 

classes in the data model have names with initial caps. Mandatory attributes and elements are 

shown in bold. Child elements are listed in the order in which they must appear. Elements 

which are not part of the XCCDF namespace are shown in italics. 

<Benchmark> 

This is the root element of the XCCDF document; it must appear exactly once. It encloses the 

entire Benchmark, and contains both descriptive information and Benchmark structural 

information. The id attribute must be a unique identifier. 

Content: elements 

Cardinality: 1 

Parent Element: none 

Attributes: id, resolved, 

Id (note: “Id” is needed only for digital signature security) 

Child Elements: status, title, description, notice, front-matter, rear-matter, reference,

cpe-list, platform, version, metadata, Profile, Value, Group, Rule, 

signature 

Note that the order of Group and Rule child elements may matter for the appearance of a 

generated document. Group and Rule children may be freely intermingled, but they must appear 

after any Value children. All the other children must appear in the order shown, and multiple 

instances of a child element must be adjacent. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

<Group> 

A Group element contains descriptive information about a portion of a Benchmark, as well as 

Rules, Values, and other Groups. A Group must have a unique id attribute to be referenced from 

other XCCDF documents or extended by other Groups. The id attribute must be a unique 

identifier. The ‘extends’ attribute, if present, must have a value equal to the id attribute of 

another Group. The ‘cluster-id’ attribute is an id; it designates membership in a cluster of Items, 

which are used for controlling Items via Profiles. The ‘hidden’ and ‘allowChanges’ attributes 

are of boolean type and default to false. The weight attribute is a positive real number. 

Content: Elements 

Cardinality: 0-n 

Parent Elements: Benchmark, Group 

Attributes: id, cluster-id, extends, hidden, prohibitChanges, selected, weight, 

Id 

Child Elements: status, version, title, description, warning, question, reference, 

rationale, platform, requires, conflicts, Value, Group, Rule 

All child elements are optional, but every group should have a title, as this will help human 

editors and readers understand the purpose of the Group. Group and Rule children may be freely 

intermingled. All the other children must appear in the order shown, and multiple instances of a 

child element must be adjacent. 

The extends attribute allows a Benchmark author to define a group as an extension of another 

group. The example XML fragment below shows an example of an extended and extending 

Group. 

Example 2 – A Simple XCCDF Group 

 <cdf:Group id="basegrp" selected="0" hidden="1"> 

 <cdf:title>Example Base Group</cdf:title> 

 <cdf:reference>Consult the vendor documentation.</cdf:reference> 

 </cdf:Group> 

 <cdf:Group extends="basegrp" id="fileperm" selected="1"> 

 <cdf:title>File Permissions</cdf:title> 

 <cdf:description> 

 Rules related to file access control and 

 user permissions. 

 </cdf:description> 

 <cdf:question> 

 Include checks for file access controls? 

 </cdf:question> 

 <cdf:reference href="http://www.vendor.com/docs/perms.html"> 

 Administration manual, permissions settings reference 

 </cdf:reference> 

 . . . 

 </cdf:Group> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

An XCCDF Group may only extend a Group that is within its visible scope. The visible scope 

includes sibling elements, siblings of ancestor elements, and the visible scope of any Group that 

an ancestor Group extended. 

Note that circular dependencies of extension are not permitted. 

<Rule> 

A Rule element defines a single Item to be checked as part of a Benchmark, or an extendable 

base definition for such Items. A Rule must have a unique id attribute, and this id is used when 

the Rule is used for extension, referenced from Profiles, or referenced from other XCCDF 

documents. 

The ‘extends’ attribute, if present, must have a value equal to the id attribute of another Rule. 

The ‘weight’ attribute must be a positive real number. Rules may not be nested. 

Content: elements 

Cardinality: 0-n 

Parent Elements: Benchmark, Group 

Attributes: id, cluster-id, extends, hidden, multiple, prohibitChanges, role, 

selected, severity, weight, Id 

Child Elements: status, version, title, description, warning, question, reference, 

rationale, platform, requires, conflicts, ident, profile-note, fixtext, 

fix, complex-check, check 

The check child element of a Rule is the vital piece that specifies how to check compliance with 

a security practice or guideline. See the description of the check element below for more 

information. Example 3 shows a very simple Rule element. 

Example 3 – A Simple XCCDF Rule 

 <cdf:Rule id="pwd-perm" selected="1" weight="6.5" severity="high"> 

 <cdf:title>Password File Permission</cdf:title> 

 <cdf:description>Check the access control on the password 

 file. Normal users should not be able to write to it. 

 </cdf:description> 

 <cdf:requires idref="passwd-exists"/> 

 <cdf:fixtext> 

 Set permissions on the passwd file to owner-write, world-read 

 </cdf:fixtext> 

 <cdf:fix strategy="restrict" reboot="0" disruption="low"> 

 chmod 644 /etc/passwd 

 </cdf:fix> 

 <cdf:check system="http://www.mitre.org/XMLSchema/oval"> 

 <cdf:check-content-ref href="ovaldefs.xml" name="OVAL123"/> 

 </cdf:check> 

 </cdf:Rule> 

 45 
SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

An XCCDF Rule may only extend a Rule that is within its visible scope. The visible scope 

includes sibling Rules, Rules that are siblings of ancestor Groups, and the visible scope of any 

Group that an ancestor Group extended. 

Circular dependencies of extension may not be defined. 

<Value> 

A Value element represents a named parameter whose title or value may be substituted into other 

strings in the Benchmark (depending on the form of processing to which the Benchmark is being 

subjected), or it may represent a basis for the definition of such parameters via extension. A 

Value object must have a unique id attribute to be referenced for substitution or extension or for 

inclusion in another Benchmark. 

A Value object may appear as a child of the Benchmark, or as a child of a Group. Value objects 

may not be nested. The value and default child elements must appear first. 

Content: elements 

Cardinality: 0-n 

Parent Elements: Benchmark, Group 

Attributes: id, cluster-id, extends, hidden, prohibitChanges, operator, type, 

interactive, interfaceHint, Id 

Child Elements: status, version, title, description, warning, question, reference, 

value, default, match, lower-bound, upper-bound, choices, source 

The type attribute is optional, but if it appears it must be one of ‘number’, ‘string’, or ‘boolean’. 

A tool performing tailoring processing may use this type name to perform user input validation. 

Example 4, below, shows a very simple Value object. 

Example 4 – Example of a Simple XCCDF Value 

 <cdf:Value id="web-server-port" type="number" operator="equals"> 

 <cdf:title>Web Server Port</cdf:title> 

 <cdf:description>TCP port on which the server listens 

 </cdf:description> 

 <cdf:value>12080</cdf:value> 

 <cdf:default>80</cdf:default> 

 <cdf:lower-bound>0</cdf:lower-bound> 

 <cdf:upper-bound>65535</cdf:upper-bound> 

 </cdf:Value> 

(Note that the match element applies only for validation during XCCDF tailoring, while the 

operator attribute applies only for rule checking. People often confuse these.) 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

<Profile> 

A Profile element encapsulates a tailoring of the Benchmark. It consists of an id, descriptive text 

properties, and zero or more selectors that refer to Group, Rule, and Value objects in the 

Benchmark. There are three selector elements: select, set-value, and refine-value. 

Profile elements may only appear as direct children of the Benchmark element. A Profile may 

be defined as extending another Profile, using the ‘extends’ attribute. 

Content: elements 

Cardinality: 0-n 

Parent Elements: Benchmark 

Attributes: abstract, id, extends, prohibitChanges, Id, note-tag

Child Elements: status, version, title, description, reference, platform, select, 

set-value, refine-value, refine-rule 

Profiles are designed to support encapsulation of a set of tailorings. A Profile implicitly includes 

all the Groups and Rules in the Benchmark, and the select element children of the Profile affect 

which Groups and Rules are selected for processing when the Profile is in effect. The example 

below shows a very simple Profile. 

Example 5 – Example of a Simple XCCDF Profile 

 <cdf:Profile id="strict" prohibitChanges="1" 

 extends="lenient" note-tag="strict-tag"> 

 <cdf:title>Strict Security Settings</cdf:title> 

 <cdf:description> 

 Strict lockdown rules and values, for hosts deployed to 

 high-risk environments. 

 </cdf:description> 

 <cdf:set-value idref="password-len">10</cdf:set-value> 

 <cdf:refine-value idref="session-timeout" selector="quick"/> 

 <cdf:refine-rule idref="session-auth-rule" selector="harsh"/> 

 <cdf:select idref="password-len-rule" selected="1"/> 

 <cdf:select idref="audit-cluster" selected="1"/> 

 <cdf:select idref="telnet-disabled-rule" selected="1"/> 

 <cdf:select idref="telnet-settings-cluster" selected="0"/> 

</cdf:Value> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

<TestResult> 

The TestResult object encapsulates the result of applying a Benchmark to one target system. The 

TestResult element normally appears as the child of the Benchmark element, although it may 

also appear as the top-level element of a file. 

Content: elements 

Cardinality: 0-n 

Parent Elements: Benchmark 

Attributes: id, start-time, end-time, Id 

Child Elements: title, remark, profile, set-value, target, target-address, target-facts, 

rule-result, score 

The id attribute is a mandatory unique-id for a test result. The start-time and end-time attributes 

must have the format of a timestamp; the end-time attribute is mandatory, and gives the time that 

the application of the Benchmark completed. 

The example below shows a TestResult object with a few rule-result children. 

Example 6 – Example of XCCDF Benchmark Test Results 

 <cdf:TestResult id="ios-test5" end-time="2004-09-25T7:45:02-04:00" 

 xmlns:cdf="http://checklists.nist.gov/xccdf/1.1"> 

 <cdf:benchmark href="ios-sample-12.4.xccdf.xml"/> 

 <cdf:title>Sample Results Block</cdf:title> 

 <cdf:remark>Test run by Bob on Sept 25</cdf:remark> 

 <cdf:target>lower.test.net</cdf:target> 

 <cdf:target-address>192.168.248.1</cdf:target-address> 

 <cdf:target-address>2001:8::1</cdf:target-address> 

 <cdf:target-facts> 

 <cdf:fact type="string" name="urn:xccdf:fact:ethernet:MAC"> 

 02:50:e6:c0:14:39 

 </cdf:fact> 

 <cdf:fact name="urn:xccdf:fact:OS:IOS">1</cdf:fact> 

 </cdf:target-facts> 

 <cdf:set-value idref="exec-timeout-time">10</cdf:set-value> 

 <cdf:rule-result idref ="ios12-no-finger-service" 

 time="2004-09-25T13:45:00-04:00"> 

 <cdf:result>pass</cdf:result> 

 </cdf:rule-result> 

 <cdf:rule-result idref ="req-exec-timeout" 

 time="2004-09-25T13:45:06-04:00"> 

 <cdf:result>fail</cdf:result> 

 <cdf:instance>console</cdf:instance> 

 <cdf:fix> 

 line console 

 exec-timeout 10 0 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 </cdf:fix> 

 </cdf:rule-result> 

 <cdf:score>67.5</cdf:score> 

</cdf:TestResult> 

<benchmark> 

This simple element may only appear as the child of a TestResult. It indicates the Benchmark 

for which the TestResult records results. It has one attribute, which gives the URI of the 

Benchmark XCCDF document. It must be an empty element. 

Content none 

Cardinality: 0-1 

Parent Elements: TestResult 

Attributes: href

Child Elements: none 

The Benchmark element should be used only in a standalone TestResult file (an XCCDF 

document file whose root element is TestResult). 

<check> 

This element holds a specification for how to check compliance with a Rule. It may appear as a 

child of a Rule element, or in somewhat abbreviated form as a child of a rule-result element 

inside a TestResult object. 

The child elements of the check element specify the values to pass to a checking engine, and the 

logic for the checking engine to apply. The logic may be embedded directly as inline text or 

XML data, or may be a reference to an element of an external file indicated by a URI. If the 

compliance checking system uses XML namespaces, then the system attribute for the system 

should be its namespace. The default or nominal content for a check element is a compliance 

test expressed as an OVAL Definition or a reference to an OVAL Definition, with the system 

attribute set to the OVAL namespace. 

The check element may also be used as part of a TestResult rule-result element; in that case it 

holds or refers to detailed output from the checking engine. 

Content: elements 

Cardinality: 0-n 

Parent Elements: Rule, rule-result 

Attributes: id, selector, system 

Child Elements: check-export, check-content-ref, check-content 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

A check element may have a selector attribute, which may be referenced from a Benchmark 

Profile as a means of refining the application of the Rule. When Profiles are not used, then all 

check elements with non-empty selectors are ignored. 

Several check elements may appear as children of the same Rule element. Sibling check 

elements must have different values for the combination of their selector and system attributes, 

and different values for their id attribute (if any). A tool processing the Benchmark for 

compliance checking must pick at most one check or complex-check element to process for each 

Rule. 

The check element may contain zero or more check-export elements, followed by zero or more 

check-content-ref elements, followed by at most one check-content element. If two or more 

check-content-ref elements appear, then they represent alternative locations from which a tool 

may obtain the check content. Tools should process the alternatives in order, and use the first 

one found. If both check-content-ref elements and check-content elements appear, tools should 

use the check-content only if all references are inaccessible. 

When a check element is a child of a rule-result object check-export elements must not appear. 

<check-export> 

This specifies a mapping from an XCCDF Value object to a checking system variable. The 

value-id attribute must match the id attribute of a Value object in the Benchmark. 

Content: none 

Cardinality: 0-n 

Parent Elements: check 

Attributes: value-id, export-name 

Child Elements: none 

<check-content> 

This element holds the actual code of a Benchmark compliance check, in the language or system 

specified by the check element’s system attribute. Exactly one of check-content or checkcontent-ref must appear in each check element. The body of this element can be any XML, but 

cannot contain any XCCDF elements. XCCDF tools are not required to process this element; 

typically it will be passed to a checking system or engine. 

Content: any non-XCCDF 

Cardinality: 0-1 

Parent Elements: check 

Attributes: none 

Child Elements: special 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

<check-content-ref> 

This element points to a Benchmark compliance check, in the language or system specified by 

the check element’s system attribute. Exactly one of check-content or check-content-ref must 

appear in each check element. The ‘href’ attribute identifies the document, and the optional 

name attribute may be used to refer to a particular part, element, or component of the document. 

Content: none 

Cardinality: 0-n 

Parent Elements: check 

Attributes: href, name 

Child Elements: none 

<choices> 

The choices element may be a child of a Value, and it enumerates one or more legal values for 

the Value. If the boolean ‘mustMatch’ attribute is true, then the list represents all the legal 

values; if mustMatch is absent or false, then the list represents suggested values, but other values 

might also be legal (subject to the parent Value’s upper-bound, lower-bound, or match 

attributes). The choices element may have a selector attribute that is used for tailoring via a 

Profile. The list given by this element is intended for use during tailoring and document 

generation; it has no role in Benchmark compliance checking. 

Content: elements 

Cardinality: 0-n 

Parent Elements: Value 

Attributes: mustMatch, selector 

Child Elements: choice 

<choice> 

This string element is used to hold a possible legal value for a Value object. It must appear as 

the child of a choices element, and has no attributes or child elements. 

Content: string 

Cardinality: 1-n 

Parent Elements: choices 

Attributes: none 

Child Elements: none 

If a tool presents the choice values from a choices element to a user, they should be presented in 

the order in which they appear. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

<complex-check> 

This element may only appear as a child of a Rule. It contains a boolean expression composed 

of operators (and, or, not) and individual checks. 

Content: elements 

Cardinality: 0-1 

Parent Elements: Rule 

Attributes: operator, negate 

Child Elements: complex-check, check 

Truth tables for boolean operation in complex checks are given below; all the abbreviations in 

the truth tables come from the description of the ‘result’ element in the TestResult object (see 

page 48). 

With an “AND” operator, the complex-check evaluates to Pass only if all of its enclosed terms 

(checks and complex-checks) evaluate to Pass. For purposes of evaluation, Pass (P) and Fixed 

(X) are considered equivalent. The truth table for “AND” is given below. 

AND P F U E N 

P P F U E P 

F F F F F F 

U U F U U U 

E E F U E E 

N P F U E N 

The ‘OR’ operator evaluates to Pass if any of its enclosed terms evaluate to Pass. The truth table 

for “OR” is given below. 

OR P F U E N 

P P P P P P 

F P F U E F 

U P U U U U 

E P E U E E 

N P F U E N 

If the negate attribute is set to true, then the result of the complex-check must be complemented 

(inverted). The full truth table for negation is given below. 

P F U E N 

not F P U E N 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

The example below shows a complex-check with several components. 

Example 7 – Example of XCCDF Complex Check 

<cdf:complex-check operator="OR"> 

 <cdf:check system="http://oval.mitre.org/XMLSchema/oval"> 

 <cdf:check-content-ref href="xpDefs.xml" name="XP-P1"/> 

 </cdf:check> 

 <cdf:complex-check operator="AND" negate="1"> 

 <cdf:check system="http://oval.mitre.org/XMLSchema/oval"> 

 <cdf:check-content-ref href="xpDefs.xml" name="XP-CX"/> 

 </cdf:check> 

 <cdf:check system="http://www.cisecurity.org/xccdf/interactive/1.0"> 

 <cdf:check-content-ref href="xpInter.xml" name="XP-6"/> 

 </cdf:check> 

 </cdf:complex-check> 

</cdf:complex-check> 

<conflicts> 

The conflicts element may be a child of any Group or Rule, and it specifies a list of the id 

properties of other Group or Rule item whose selection conflicts with this one. Each conflicts 

element specifies a single conflicting Item using its ‘idref’ attribute; if the semantics of the 

Benchmark need multiple conflicts, then multiple conflicts elements may appear. A conflicts 

element must be empty. 

Content: none 

Cardinality: 0-n 

Parent Elements: Group, Rule 

Attributes: idref 

Child Elements: none 

<cpe-list> 

This element holds names and descriptions for one or more platforms, using the XML schema 

defined for the Common Platform Enumeration (CPE) [16]. CPE Names are URIs, and may be 

used for all platform identification in an XCCDF document. 

Content: elements (from the CPE schema) 

Cardinality: 0-1 

Parent Elements: Benchmark 

Attributes: none 

Child Elements: cpe-item 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

<default> 

This string element is used to hold the default or reset value of a Value object. It may only 

appear as a child of a Value element, and has no child elements. This element may have a 

selector attribute, which may be used to designate different defaults for different Benchmark 

Profiles. 

Content: string 

Cardinality: 0-n 

Parent Elements: Value 

Attributes: selector 

Child Elements: none 

<description> 

This element provides the descriptive text for a Benchmark, Rule, Group, or Value. It has no 

attributes. Multiple description elements may appear with different values for their xml:lang 

attribute (see also next section). 

Content: mixed 

Cardinality: 0-n 

Parent Elements: Benchmark, Group, Rule, Value, Profile 

Attributes: xml:lang, override

Child Elements: sub, xhtml elements

The ‘sub’ element may appear inside a description, and in many other descriptive text elements. 

During document generation, each instance of the ‘sub’ element should be replaced by the title of 

the Item or other object to which it refers. For more information, see page 36. 

<fact> 

This element holds a single type-name-value fact about the target of a test. The name is a URI. 

Pre-defined names start with “urn:xccdf:fact”, but tool developers may define additional 

platform-specific and tool-specific facts. 

Content: string 

Cardinality: 0-n 

Parent Elements: target-facts 

Attributes: name, type

Child Elements: none

The following types are supported: “number”, “string”, and “boolean” (the default). 

 54 
SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

<fix> 

This element may appear as the child of a Rule element, or a rule-result element. When it 

appears as a child of a Rule element, it contains string data for a command, script, or procedure 

that should bring the target into compliance with the Rule. It may not contain XHTML 

formatting. The fix element may contain XCCDF Value substitutions specified with the sub 

element, or instance name substitution specified with an instance element. 

Content mixed 

Cardinality: 0-n 

Parent Elements: Rule, rule-result 

Attributes: id, complexity, disruption, platform, reboot, strategy, system

Child Elements: instance, sub 

The fix element supports several attributes that the Rule author can use to provide additional 

information about the remediation that the fix element contains. The attributes and their 

permissible values are listed below. 

Attribute Values 

id A local id for the fix, which allows fixtext elements 

to refer to it. These need not be unique; several fix 

elements might have the same id but different values 

for the other attributes. 

complexity A keyword that indicates the complexity or difficulty 

of applying the fix to the target. Allowed values: 

• unknown – default, complexity not defined 

• low – the fix is very simple to apply 

• medium –fix is moderately difficult or complex 

• high – the fix is very complex to apply 

disruption A keyword that designates the potential for disruption 

or degradation of target operation. Allowed values: 

• unknown – default, disruption not defined 

• low – little or no disruption expected 

• medium – potential for minor or short-lived 

disruption 

• high – potential for serious disruption 

platform A platform identifier; this should appear on a fix 

when the content applies to only one platform out of 

several to which the Rule could apply. 

reboot Boolean – if remediation will require a reboot or hard 

reset of the target (‘1’ means reboot required) 

strategy A keyword that designates the approach or method 

that the fix uses. Allowed values: 

• unknown – default, strategy not defined 

 55 
SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Attribute Values 

• configure – adjust target configuration/settings 

• patch – apply a patch, hotfix, update, etc. 

• disable – turn off or uninstall a target component 

• enable – turn on or install a target component 

• restrict – adjust permissions, access rights, 

filters, or other access restrictions 

• policy – remediation requires out-of-band 

adjustments to policies or procedures 

• combination – strategy is a combination or two 

or more approaches

system A URI that identifies the scheme, language, or engine 

for which the fix is written. Several general URIs are 

defined, but platform-specific URIs may be expected. 

(For a list of pre-defined fix system URIs, see 

Appendix C.) 

The platform attribute defines the platform for which the fix is intended, if its parent Rule 

applied to multiple platforms. The value of the platform attribute should be one of the platform 

strings defined for the Benchmark. If the fix’s platform attribute is not given, then the fix applies 

to all platforms to which its enclosing Rule applies. 

As a special case, fix elements may also appear as children of a rule-result element in a 

TestResult. In this case, the fix element should not any child elements, its content should be a 

simple string. When a fix element is the child of rule-result, it is assumed to have been 

‘instantiated’ by the testing tool, and any substitutions or platform selection already made. 

<fixtext> 

This element, which may only appear as a child of a Rule element, provides text that explains 

how to bring a target system into compliance with the Rule. Multiple instances may appear in a 

Rule, with different attribute values. 

Content: mixed 

Cardinality: 0-n 

Parent Elements: Rule 

Attributes: xml:lang, fixref, disruption, reboot, strategy, override 

Child Elements: sub, xhtml elements

The fixtext element and its counterpart, the fix element, are fairly complex. They can accept a 

number of attributes that describe aspects of the remediation. The xml:lang attribute designates 

the locale for which the text was written; it is expected that fix elements usually will be localeindependent. The following attributes may appear on the fixtext element (for details about most 

of them, refer to the table under the fix element definition, p. 55). 

Attribute Values 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Attribute Values 

fixref A reference to the id of a fix element 

complexity A keyword that indicates the difficulty or complexity 

of applying the described fix to the target 

disruption A keyword that designates the potential for disruption 

or degradation of target operation

reboot Boolean – if the remediation described in the fixtext 

will require a reboot or reset of the target 

strategy A keyword that designates the approach or method 

that the fix uses 

The fixtext element may contain XHTML elements, to aid in formatting. 

<front-matter> 

This element contains textual content intended for use during Document Generation processing 

only; it is introductory matter that should appear at or near the beginning of the generated 

document. Multiple instances may appear with different xml:lang values. 

Content: mixed 

Cardinality: 0-n 

Parent Elements: Benchmark 

Attributes: xml:lang 

Child Elements: sub, xhtml elements

<ident> 

This element contains a string (name) which is a long-term globally meaningful identifier in 

some naming scheme. The content of the element is the name, and the system attribute contains 

a URI which designates the organization or scheme that assigned the name (see Section 8 for 

assigned URIs). 

Content: string 

Cardinality: 0-n 

Parent Elements: Benchmark 

Attributes: system 

Child Elements: none

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

<instance> 

The instance element may appear in two situations. First, it may appear as part of a TestResult, 

as a child of a rule-result element; in that situation it contains the name of a target component to 

which a Rule was applied, in the case of multiply-instantiated rules. 

Content: string 

Cardinality: 0-n 

Parent Elements: rule-result 

Attributes: context, parentContext 

Child Elements: none

If the context attribute is omitted, the value of the context defaults to “undefined”. At most one 

instance child of a rule-result may have a context of “undefined”. 

Second, the instance element may appear as part of a Rule, as a child of the fix element. In that 

situation it represents a place in the fix text where the name of a target component should be 

substituted, in the case of multiply-instantiated rules. 

Content: none 

Cardinality: 0-n 

Parent Elements: fix 

Attributes: context 

Child Elements: none

If the context attribute is omitted, the value of the context defaults to “undefined”. 

<lower-bound> 

This element may appear zero or more times as a child of a Value element. It is used to 

constrain value input during tailoring, when the Value’s type is “number”. It contains a number; 

values supplied by the user for tailoring the Benchmark must be no less than this number. This 

element may have a selector tag attribute, which identifies it for Value refinement by a Profile. 

If more than one lower-bound element appears as the child of a Value, at most one of them may 

omit the selector attribute. 

Content: number 

Cardinality: 0-n 

Parent Elements: Value 

Attributes: selector 

Child Elements: none 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

<match> 

This element may appear zero or more times as a child of a Value element. It is used to 

constrain value input during tailoring. It contains a regular expression that a user’s input for the 

value must match. This element may have a selector tag attribute, which identifies it for Value 

refinement by a Profile. If more than one match element appears as the child of a Value, at most 

one of them may omit the selector attribute. 

Content: string 

Cardinality: 0-n 

Parent Elements: Value 

Attributes: selector 

Child Elements: none 

<message> 

This element is optional, but may appear one or more times as a child of a rule-result element 

inside a TestResult object. It holds a single informational or error message that was returned by 

the checking engine. 

Content: string 

Cardinality: 0-n 

Parent Elements: rule-result 

Attributes: severity 

Child Elements: none 

The severity attribute denotes the seriousness or conditions of the message. In XCCDF schema 

version 1.1.3.2 there are three message severity values: “error”, “warning”, and “info”. These 

elements do not affect scoring; they are present merely to convey diagnostic information from 

the checking engine. XCCDF tools that deal with TestResult data might choose to log these 

messages or display them to the user. 

<metadata> 

The metadata element is optional, but may appear one or more times as a child of the Benchmark 

element. It contains document metadata expressed in XML. The default format for Benchmark 

document metadata is the Dublin Core Metadata Initiative (DCMI) Simple DC Element 

specification, as described in [11] and [13]. An example of the default format is shown in 

Example 8. Tools, especially document generation tools, should be prepared to process Dublin 

Core metadata in this element. 

Content: element 

Cardinality: 0-n 

Parent Elements: Benchmark 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Attributes: none 

Child Elements: non-XCCDF (Dublin Core elements recommended)

Another suitable metadata format for XCCDF Benchmarks is the XML description format 

mandated by NIST for its Security Configuration Checklist Program [12]. 

Example 8 – Example of Benchmark Metadata Expressed with Dublin Core Elements 

 <cdf:metadata xmlns:dc="http://purl.org/dc/elements/1.1/"> 

 <dc:title>Security Benchmark for Ethernet Hubs</dc:title> 

 <dc:creator>James Smith</dc:creator> 

 <dc:publisher>Center for Internet Security</dc:publisher> 

 <dc:subject>network security for layer 2 devices</dc:subject> 

 </cdf:metadata> 

<model> 

This element contains a specification for a suggested scoring model. This element may only 

appear as a child of a Benchmark, and has one mandatory attribute: the URI of the scoring 

model. Some models may need additional parameters; to support such a model, zero or more 

‘param’ elements may appear as children of the ‘model’ element. 

Content: element 

Cardinality: 0-n 

Parent Elements: Benchmark 

Attributes: system 

Child Elements: param 

This specification defines the following three scoring model URIs; compliance checking tool 

developers may define additional models. For more information see Section 3.3. 

• urn:xccdf:scoring:default – this is the default weighted aggregated model. All 

tools must support this model, and it is the default for Benchmarks that do not 

include any other model specifications. 

• urn:xccdf:scoring:flat – this simple model computes the sum of the weights of 

rules that pass. All tools should support this model. 

• urn:xccdf:scoring:flat-unweighted – this simplest of all models simply 

computes the number of rules that passed. It does not use weights. All tools should 

support this model. 

<new-result> 

An override rule result status. This element appears in an override element, inside a rule-result 

element, in a TestResult object. Its content must be one of the result status values listed in 

Section 3.2. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Content: string 

Cardinality: 1 

Parent Elements: override 

Attributes: none 

Child Elements: none 

<notice> 

This string element may only appear as the child of a Benchmark element, and supplies legal 

notice or copyright text about the Benchmark document. It may not contain any child elements. 

The id attribute must be a unique identifier. 

Content: mixed 

Cardinality: 0-n 

Parent Elements: Benchmark 

Attributes: id 

Child Elements: xhtml elements 

The notice element may contain XHTML markup to give it internal structure and formatting. 

<old-result> 

This element holds an overridden rule result status. This element appears in an override element, 

inside a rule-result element, in a TestResult object. Its content must be one of the result status 

values listed in Section 3.2. 

Content: string 

Cardinality: 1 

Parent Elements: override 

Attributes: none 

Child Elements: none 

<override> 

This element may appear only as a child of a rule-result, and represents a human override of a 

Benchmark rule check result. It consists of five parts: a timestamp, the name of the human 

authority for the override, the old and new result status values, and remark text. 

Content: elements 

Cardinality: 0-n 

Parent Elements: rule-result 

Attributes: time, authority 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Child Elements: old-result, new-result, remark 

Example 9, below, shows how an override block would appear in a rule-result. 

Example 9 – Example of rule-result Element with an Override 

<cdf:rule-result idref="rule76" 

 time="2005-04-26T14:38:19Z" severity="low"> 

 <cdf:result>pass</cdf:result> 

 <cdf:override time="2005-04-26T15:03:20Z" authority="Bob Smith"> 

 <cdf:old-result>fail</cdf:old-result> 

 <cdf:new-result>pass</cdf:new-result> 

 <cdf:remark> 

 Manual inspection showed this rule be satisfied. The 

 relevant registry key was protected per policy, but with 

 a more restrictive ACL than the benchmark was designed 

 to check. The rule result has been overridden to ‘pass’. 

 </cdf:remark> 

 </cdf:override> 

 <cdf:instance context="registry"> 

 HKLM\SOFTWARE\Policies 

 </cdf:instance> 

 <cdf:check system="http://www.mitre.org/XMLSchema/oval"> 

 <cdf:check-content-ref href="oval-out.xml" name="OVAL123"/> 

 </cdf:check> 

</cdf:rule-result> 

Note: if an override is added to a rule-result, then it will break any digital signature applied to the 

enclosing TestResult object. 

<param> 

This element may appear only as a child of a model element. It supplies a parameter that the 

compliance checking tool will need when computing the score using that model. None of the 

scoring models defined in the XCCDF 1.1 specification require parameters, but proprietary 

models may. 

Content: string 

Cardinality: 0-n 

Parent Elements: model 

Attributes: name 

Child Elements: none 

Param elements with equal values for the name attribute may not appear as children of the same 

model element. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

<plain-text> 

This element holds a re-usable chunk of text for a Benchmark. It may be used anywhere that 

XHTML content or the XCCDF sub element may be used. Each plain-text definition must have 

a unique id. 

Content: string 

Cardinality: 0-n 

Parent Elements: Benchmark, 

Attributes: id 

Child Elements: none 

Note that plain-text definitions may only appear as children of Benchmark. The id on a plaintext definition must not be equal to any of the ids on Value, Group, or Rule objects. 

<platform> 

The ‘platform’ element specifies a target platform for the Benchmark or a particular Item, 

Profile, or TestResult. This element has no content; the platform identifier appears in the ‘idref’ 

attribute. Multiple ‘platform’ elements may appear as children of a Benchmark, Item, or Profile, 

if the Benchmark or Item is suitable for multiple kinds of target systems. 

Content: none 

Cardinality: 0-n 

Parent Elements: Benchmark, Group, Rule, Value, TestResult 

Attributes: idref, override 

Child Elements: none 

The platform element is optional. It indicates a platform with a CPE Name. The CPE Name 

may be defined in the Benchmark cpe-list element. 

The override attribute may not appear when the platform element is a child of a TestResult. 

<platform-definitions>, <Platform-Specification> 

Each of these elements contains information about platforms to which the Benchmark may 

apply. The <platform-definitions> element contains a set of platform component and platform 

definitions using the CIS platform schema; it is permitted in XCCDF 1.1 for compatibility with 

1.0. Both of these elements are deprecated, and appear in this specification only for backward 

compatibility. Common Platform Enumeration (CPE) Names should be used instead, see page 

53. 

Content: elements 

Cardinality: 0-1 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Parent Elements: Benchmark 

Attributes: none 

Child Elements: special

<profile> 

This element specifies the Benchmark Profile used in applying a Benchmark; it can appear only 

as a child of a TestResult element. 

Content: none 

Cardinality: 0-1 

Parent Elements: TestResult 

Attributes: idref 

Child Elements: none 

<profile-note> 

This element holds descriptive text about how one or more Profiles affect a Rule. It can appear 

only as a child of the Rule element. 

Content: mixed 

Cardinality: 0-n 

Parent Elements: Rule 

Attributes: tag, xml:lang

Child Elements: sub, xhtml elements 

The mandatory ‘tag’ attribute holds an identifier; Profiles can refer to this identifier using the 

‘note-tag’ attribute. 

<question> 

This element specifies an interrogatory string with which to prompt the user during tailoring. It 

may also be included into a generated document. Note that this element may not contain any 

XCCDF child elements, nor may it contain XHTML formatting elements. Multiple instances 

may appear with different xml:lang attributes. 

Content: string 

Cardinality: 0-n 

Parent Elements: Group, Rule, Value 

Attributes: xml:lang, override

Child Elements: none 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

For Rule and Group objects, the question text should be a simple binary (yes/no) question, 

because tailoring for Rules and Groups is for selection only. For Value objects, the question 

should reflect the designed data value needed for tailoring. 

<rationale> 

This element, which may appear as a child of a Group or Rule element, provides text that 

explains why that Group or Rule is important to the security of a target platform. 

Content: mixed 

Cardinality: 0-n 

Parent Elements: Group, Rule 

Attributes: xml:lang, override

Child Elements: sub, xhtml elements

<rear-matter> 

This element contains textual content intended for use during Document Generation processing 

only; it is concluding material that should appear at or near the end of the generated document. 

Multiple instances may appear with different xml:lang attributes. 

Content: mixed 

Cardinality: 0-n 

Parent Elements: Benchmark 

Attributes: xml:lang

Child Elements: sub, xhtml elements

<reference> 

This element provides supplementary descriptive text for a Benchmark, Rule, Group, or Value. 

It may have a simple string value, or a value consisting of simple Dublin Core elements as 

described in [13]. It may also have an attribute, ‘href’, giving a URL for the referenced resource. 

Multiple reference elements may appear; a document generation processing tool may 

concatenate them, or put them into a reference list, and may choose to number them. 

Content: string or elements 

Cardinality: 0-n 

Parent Elements: Benchmark, Group, Rule, Value, Profile 

Attributes: xml:lang, href 

Child Elements: none or Dublin Core Elements 

References should be given as Dublin Core descriptions; a bare string is allowed for simplicity. 

If a bare string appears, then it is taken to be the string content for a Dublin Core ‘title’ element. 

For more information, consult [11]. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

<refine-rule> 

This element adjusts the check tailoring selector, weight, severity, and role properties of a Rule. 

It has five attributes: the id of a Rule (mandatory), and adjusted values for check selector, 

weight, severity, and role (all optional). 

Content: none 

Cardinality: 0-n 

Parent Elements: Profile 

Attributes: idref, role, selector, severity, weight

Child Elements: none 

The ‘idref’ attribute must match the id attribute of a Rule, or a cluster-id of one or more Items in 

the Benchmark. The ‘idref’ attribute values of sibling refine-rule element children of a Profile 

must be different. When the ‘idref’ attribute refers to a Group, or if some of the Items in a 

cluster are Groups, then only the ‘weight’ attribute applies to them. 

Selector tags apply only to the check children of a Rule. If the selector tag specified in a refinerule element in a Profile does not match any of the selectors specified on any of the check 

children of a Rule, then the check child element without a selector attribute must be used. 

<refine-value> 

This element specifies the selector tag to be applied when tailoring a Value during use of a 

particular Profile. It has three attributes: the id of a Value or Item cluster (mandatory), the id of a 

Value selector tag, and a new setting for the Value operator. 

Content: none 

Cardinality: 0-n 

Parent Elements: Profile 

Attributes: idref, operator, selector

Child Elements: none 

The ‘idref’ attribute must match the id attribute of a Value, or a cluster-id of one or more Items 

in the Benchmark. The ‘idref’ attribute values of sibling refine-value element children of a 

Profile must be different. 

The ‘operator’ attribute of the refine-value element can be used to override or replace the 

operator attribute of a Value. This is useful for refining the semantics of a Value. 

Selector tags apply to the following child elements of Value: choices, default, value, match, 

lower-bound, and upper-bound. If the selector tag specified in a refine-value element in a Profile 

does not match any of the selectors specified on any of the Value children, then the child with no 

selector tag is used. The example below illustrates how selector tags and the refine-value 

element work. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Example 10 – Example of Profile refine-value Selector Tags 

 <cdf:Value id="pw-length" type="number" operator="equals"> 

 <cdf:title>Minimum password length policy</cdf:title> 

 <cdf:value>8</cdf:value> 

 <cdf:value selector="high">14</cdf:value> 

 <cdf:lower-bound>8</cdf:lower-bound> 

 <cdf:lower-bound selector="high">12</cdf:lower-bound> 

 </cdf:Value> 

 <cdf:Profile id="enterprise-internet"> 

 <cdf:title>Enterprise internet server profile</cdf:title> 

 <cdf:refine-value idref="pw-length" selector="high"/> 

 </cdf:Profile> 

 <cdf:Profile id="home"> 

 <cdf:title>Home host profile</cdf:title> 

 </cdf:Profile> 

<remark> 

The remark element may appear as the child of a TestResult or override element; it contains a 

textual remark about the test. 

Content: string 

Cardinality: 0-n (TestResult), 1 (override) 

Parent Elements: TestResult, override 

Attributes: xml:lang 

Child Elements: none

The remark content may not contain any XHTML tags or other structure; it must be a plain 

string. 

<requires> 

The requires element may be a child of any Group or Rule, and it specifies the id properties of 

one or more other Group or Rule which, at least one of which must be selected in order for this 

Item to be selected. In a sense, the requires element is the opposite of the conflicts element. 

Each requires element specifies a list of one or more required Items by their ids, using the ‘idref’ 

attribute. If more than one id is given, then if at least one of the specified Groups or Rules is 

selected, then the requirement is met. 

Content: none 

Cardinality: 0-n 

Parent Elements: Group, Rule 

Attributes: idref 

Child Elements: none 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

<result> 

This simple element holds the verdict of applying a Benchmark Rule to a target or component of 

a target. It may have only one of nine values: “pass”, “fail”, “error”, “unknown”, “notchecked”, 

“notapplicable”, “notselected”, “fixed” or “informational”. For more information see page 30. 

Content: string 

Cardinality: 1 

Parent Elements: rule-result 

Attributes: None 

Child Elements: None 

<rule-result> 

This element holds the result of applying a Rule from the Benchmark to a target system or 

component of a target system. It may only appear as the child of a TestResult element. 

Content: elements 

Cardinality: 0-n 

Parent Elements: TestResult 

Attributes: idref, role, time, severity, version 

Child Elements: result, override, ident, message, instance, fix, check 

The ‘idref’ attribute of a rule-result element must refer to a Rule element in the Benchmark. The 

result child element expresses the result (pass, fail, error, etc.) of applying the Rule to the target 

system. If the Rule is multiply instantiated, the instance elements indicate the particular system 

component. If present, the override element provides information about a human override of a 

computed result status value. 

<score> 

This element contains the weighted score for a Benchmark test, as a real number. Scoring 

models are defined in Section 3.3. This element may only appear as a child of a TestResult 

element. 

Content: string (non-negative number) 

Cardinality: 1-n 

Parent Elements: TestResult 

Attributes: system, maximum 

Child Elements: none 

The system attribute, a URI, identifies the scoring model (see the description of the model 

element on page 60 for a list of pre-defined models). If the system attribute does not appear, 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

then the model used was the default model. The maximum attribute, a real number, gives the 

maximum possible value of the score for this Benchmark test. If the maximum attribute does not 

appear, then it is taken to have a value of 100. 

<select> 

This element is part of a Profile; it overrides the selected attribute of a Rule or Group. Two 

attributes must be given with this element: the id of a Rule or Group (idref), and a boolean value 

(selected). If the boolean value is given as true, then the Rule or Group is selected for this 

Profile, otherwise it is unselected for this Profile. 

Content: none 

Cardinality: 0-n 

Parent Elements: Profile 

Attributes: idref, selected 

Child Elements: none 

The ‘idref’ attribute must match the id attribute of a Group or Rule in the Benchmark, or the 

cluster id assigned to one or more Rules or Groups. The ‘idref’ attribute values of sibling select 

element children of a Profile must be different. 

<set-value> 

This element specifies a value for a Value object. It may appear as part of a Profile; in that case 

it overrides the value property of a Value object. It may appear as part of a TestResult; in that 

case it supplies the value used in the test. This element has one mandatory attribute and no child 

elements. 

Content: string 

Cardinality: 0-n 

Parent Elements: Profile, TestResult 

Attributes: idref 

Child Elements: none 

In the content of a Profile, the identifier given for the ‘idref’ attribute may be a cluster id, in 

which case it applies only to the Value item members of the cluster; in the context of a 

TestResult, the identifier must match the id of a Value object in the Benchmark. The ‘idref’ 

attribute values of sibling set-value element children of a Profile must be different. 

<signature> 

This element can hold an enveloped digital signature expressed according to the XML Digital 

Signature standard [9]. This element takes no attributes, and must contain exactly one element 

from the XML-Signature namespace. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Content: elements 

Cardinality: 0-1 

Parent Elements: Benchmark, Rule, Group, Value, Profile, TestResult 

Attributes: none

Child Elements Signature (in XML-Signature namespace) 

At most one enveloped signature can appear in an XCCDF document. If multiple signatures are 

needed, others must be detached signatures. 

The signature element should contain one child element, Signature from the XML-Signature 

namespace, and that Signature should contain exactly one Reference to the block enclosing the 

signature. The Reference URI should be a relative URI to the Id attribute value of the enclosing 

object. For example, if the Id="abc", then the Reference URI would be "#abc". 

<source> 

The source element contains a URI indicating where a tailoring or benchmarking tool might 

obtain the value, or information about the value, for a Value object. XCCDF does not attach any 

meaning to the URI; it may be an arbitrary community or tool-specific value, or a pointer 

directly to a resource. 

Content: none 

Cardinality: 0-n 

Parent Elements: Value 

Attributes: uri 

Child Elements: none 

If several values for the source property appear, then they represent alternative means or 

locations for obtaining the value, in descending order of preference (i.e., most preferred first). 

<status> 

This element provides a revision or standardization status for a Benchmark, along with the date 

at which the Benchmark attained that status. It must appear once in a Benchmark object, and 

may appear once in any Item. If an Item does not have its own status element, its status is that of 

its parent element. The permitted string values for status are “accepted”, “deprecated”, “draft”, 

“interim”, and “incomplete”. 

Content: string (enumerated choices) 

Cardinality: 0-n 

Parent Elements: Benchmark, Rule, Group, Value, Profile 

Attributes: date 

Child Elements: none 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

A Benchmark must have at least one status child element. 

<sub> 

This element represents a reference to a parameter value that may be set during tailoring. The 

element never has any content, and must have its single attribute, value. The value attribute must 

equal the id attribute of a Value object or plain-text definition. 

Content: none 

Cardinality: 0-n 

Parent Elements: description, fix, fixtext, front-matter, rationale, rear-matter, title, 

warning 

Attributes: idref 

Child Elements: none 

<target> 

This element gives the name or description of a target system to which a Benchmark test was 

applied. It may only appear as a child of a TestResult element. 

Content: string 

Cardinality: 1 

Parent Elements: TestResult 

Attributes: none 

Child Elements: none 

<target-address> 

This element gives the network address of a target system to which a Benchmark test was 

applied. It may only appear as a child of a TestResult element. 

Content: string 

Cardinality: 0-n 

Parent Elements: TestResult 

Attributes: none 

Child Elements: none 

<target-facts> 

The TestResult object must be able to hold an arbitrary set of facts about the target of a test. 

This element holds those facts, each one of which is a fact element. It is an optional member of 

TestResult. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Content: string 

Cardinality: 0-1 

Parent Elements: TestResult 

Attributes: none 

Child Elements: fact 

<title> 

This element provides the descriptive title for a Benchmark, Rule, Group, or Value. Multiple 

instances may appear with different languages (different values of the xml:lang attribute). 

Content: string 

Cardinality: 0-n 

Parent Elements: Benchmark, Value, Group, Rule, Profile, TestResult 

Attributes: xml:lang, override 

Child Elements: none

This element may not contain XHTML markup. 

The ‘override’ attribute controls how the title property is inherited, if the Item in which it appears 

extends another Item. 

<upper-bound> 

This element may appear zero or more times as a child of a Value element. It is used to 

constrain value input during tailoring, when the Value’s type is “number”. It contains a number; 

values supplied by the user for tailoring the Benchmark must be no greater than this number. 

This element may have a selector tag attribute, which identifies it for Value refinement by a 

Profile. If more than one upper-bound element appears as the child of a Value, at most one may 

omit the selector attribute. 

Content: number 

Cardinality: 0-n 

Parent Elements: Value 

Attributes: selector 

Child Elements: none 

<value> 

This string element is used to hold the value of a Value object. It must appear as the child of a 

Value element, and no child elements. This element may have a selector tag attribute, which 

identifies it for Value refinement by a Profile. This element may appear more than once, but at 

most one of the sibling instances of this element may omit the selector tag. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Content: String 

Cardinality: 1-n 

Parent Elements: Value 

Attributes: Selector 

Child Elements: None 

<version> 

This element gives a version number for a Benchmark, Group, Rule, Value, or Profile. The 

version number content may be any string. This element allows an optional time attribute, which 

is a timestamp of when the Object was defined. This element also allows an optional update 

attribute, which should be the URI specifying where updates to the Object may be obtained. 

Content: string 

Cardinality: 1 (Benchmark), 0-1 (all others) 

Parent Elements: Benchmark, Group, Rule, Value, Profile 

Attributes: time, update 

Child Elements: none

<warning> 

This element provides supplementary descriptive text for a Benchmark, Rule, Group, or Value. 

It has no attributes. Multiple warning elements may appear; processing tools should concatenate 

them for generating reports or documents (see also next section). 

Content: mixed 

Cardinality: 0-n 

Parent Elements: Benchmark, Group, Rule, Value 

Attributes: xml:lang, override 

Child Elements: sub, xhtml elements

This element is intended to convey important cautionary information for the Benchmark user 

(e.g., “Complying with this rule will cause the system to reject all IP packets”). Processing tools 

may present this information specially in generated documents. 

4.3. Handling Text and String Content 

This sub-section provides additional information about how XCCDF processing tools must 

handle textual content in Benchmarks. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

XHTML Formatting and Locale 

Some text-valued XCCDF elements may contain formatting specified with elements from the 

XHTML Core Recommendation. 

Many of the string and textual elements of XCCDF are listed as appearing multiple times under 

the same parent element. These elements, listed below, can have an xml:lang attribute that 

specifies the natural language locale for which they are written (e.g., “en” for English, “fr” for 

French). A processing tool should employ these attributes when possible during tailoring, 

document generation, and producing compliance reports, to create localized output. An example 

of using the xml:lang attribute is shown below. 

Example 11 – A Simple Value Object with Questions in Different Languages 

 <cdf:Value id="web-server-port" type="number"> 

 <cdf:title>Web Server Port</cdf:title> 

 <cdf:question xml:lang="en"> 

 What is the web server’s TCP port? 

 </cdf:question> 

 <cdf:question xml:lang="fr"> 

 Quel est le port du TCP du web serveur? 

 </cdf:question> 

 <cdf:value>80</cdf:value> 

</cdf:Value> 

Multiple values for the same property in a single Item are handled differently, as described 

below. Multiple instances with different values of their xml:lang attribute are always permitted; 

an Item with no value for the xml:lang attribute is taken to have the same language as the 

Benchmark itself (as given by the xml:lang attribute on the Benchmark element). 

Elements Inheritance Behavior 

description, title, fixtext, rationale, 

question, front-matter, rear-matter 

At most one instance per language; inherited 

values with the same language get replaced 

warning, reference, notice Multiple instances treated as an ordered list; 

inherited instances prepended to the list 

The platform element may also appear multiple times, each with a different id, to express the 

notion that a Rule, Group, Benchmark, or Profile applies to several different products or systems. 

String Substitution and Reference Processing 

There are three kinds of string substitution and one kind of reference processing that XCCDF 

document generation and reporting tools must support. 

1. XCCDF sub element - 

The sub element supports substitution of information from a Value object, or the string 

content of a plain-text definition. The formatting for a sub element reference to a Value 

object is implementation-dependent for document generation, as described in Section 3.3. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Formatting for a sub element reference to a plain-text definition is very simple: the string 

content of the plain-text definition replaces the sub element. 

2. XHTML object element - 

The object element supports substitutions of a variety of information from another Item 

or Profile, or the string content of a plain-text definition. To avoid possible conflicts with 

uses of an XHTML object that should not be processed specially, all XCCDF object 

references must be a relative URI beginning with “#xccdf:”. The following URI values 

can be used to refer to things from an "object" element, using the "data" attribute: 

• #xccdf:value:id

Insert the value of the plain-text block, Value, or fact with id id:. When a URI of this 

form is used, the value of the reference should be substituted for the entire “object” 

element and its content (if any). In keeping with the standard semantics of XHTML, 

if the id cannot be resolved, then the textual content of the “object” element should be 

retained. 

• #xccdf:title:id

Insert the string content of the “title” child of the Item with id id. Use the current 

language value locale setting, if any. When a URI of this form is used, the title string 

should be substituted for the entire “object” element and its content (if any). In 

keeping with the standard semantics of XHTML, if the id cannot be resolved, then the 

textual content of the “object” element should be retained. 

3. XHTML anchor (a) element - 

The anchor element can be used to create an intra-document link to another XCCDF Item 

or Profile. To avoid possible conflicts with uses of the XHTML anchor element that 

should not be processed specially, all XCCDF anchor references must be a relative URI 

beginning with “#xccdf:”. The following URI values can be used to refer to things 

from an anchor (“a”) element, using the ‘href’ attribute: 

• #xccdf:link:id

Create an intra-document link to the point in the document where the Item id is 

described. The content of the element should be the text of the link. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

5. Conclusions 

The XCCDF specification defines a means for expressing security guidance documents in a way 

that should foster development of interoperable tools and content. It is designed to permit the 

same document to serve in several roles: 

• Source code for generation of publication documents and hardcopy 

• Script for eliciting local security policy settings and values from a user 

• Structure for containing and organizing code that drives system analysis and 

configuration checking engines 

• Source code for text to appear in security policy compliance reports 

• A record of a compliance test, including the results of applying various rules 

• Structure for expressing compliance scoring/weighting decisions. 

XCCDF 1.1 was designed as a compatible extension of 1.0, based on suggestions from early 

adopters and potential users. Many features have been added, but every valid 1.0 document 

should be a valid 1.1 document, once the namespace is adjusted. The forward compatibility will 

help ensure that content written for XCCDF 1.0 will not be made obsolete by the 1.1 

specification. XCCDF 1.1.3 is a minor update of the specification and schema of XCCDF 1.1, 

mainly to add clarity and fix problems identified by initial users. 

Adoption of a common format should permit security professionals, security tool vendors, and 

system auditors to exchange information more quickly and precisely, and also permit greater 

automation of security testing and configuration checking. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

6. Appendix A – XCCDF Schema 

The XML Schema below describes XCCDF in a manner that should allow automatic validation 

of most aspects of the format. It is not possible to express all of the constraints that XCCDF 

imposes in a Schema, unfortunately, and a few of the constraints that it is possible to express 

have been omitted for simplicity. 

Whether or not to validate XCCDF XML documents is an implementation decision left to tool 

developers, but it is strongly recommended. 

XCCDF 1.1 Schema (1.1.3.2) 

<?xml version="1.0" encoding="UTF-8"?> 

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" 

 xmlns:cdf="http://checklists.nist.gov/xccdf/1.1" 

 xmlns:dc="http://purl.org/dc/elements/1.1/" 

 xmlns:cisp="http://www.cisecurity.org/xccdf/platform/0.2.3" 

 xmlns:cdfp="http://checklists.nist.gov/xccdf-p/1.1" 

 xmlns:cpe="http://cpe.mitre.org/XMLSchema/cpe/1.0" 

 xmlns:xsi="http://www.w3.org/2001/XMLSchema-Instance" 

 targetNamespace="http://checklists.nist.gov/xccdf/1.1" 

 elementFormDefault="qualified" attributeFormDefault="unqualified"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 This schema defines the eXtensible Configuration Checklist 

 Description Format (XCCDF), a data format for defining 

 security benchmarks and checklists, and for recording 

 the results of applying such benchmarks. 

 For more information, consult the specification 

 document, "Specification for the Extensible Configuration 

 Checklist Description Format", version 1.1 revision 3. 

 This schema was developed by Neal Ziring, with ideas and 

 assistance from David Waltermire. The following helpful 

 individuals also contributed ideas to the definition 

 of this schema: David Proulx, Andrew Buttner, Ryan Wilson, Matthew Kerr, 

 Stephen Quinn. Ian Crawford found numerous discrepancies between 

 this schema and the spec document. 

 Peter Mell and his colleagues also made many suggestions. 

 <version date="28 December 2006">1.1.3.2</version> 

 </xsd:documentation> 

 </xsd:annotation> 

 <!-- Import base XML namespace --> 

 <xsd:import namespace="http://www.w3.org/XML/1998/namespace" 

 schemaLocation="xml.xsd"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Import the XML namespace because this schema uses 

 the xml:lang and xml:base attributes. 

 </xsd:documentation> 

 </xsd:annotation> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 </xsd:import> 

 <!-- Import Dublin Core metadata namespace --> 

 <xsd:import namespace="http://purl.org/dc/elements/1.1/" 

 schemaLocation="simpledc20021212.xsd"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Import the simple Dublin Core namespace because this 

 schema uses it for benchmark metadata and for references. 

 </xsd:documentation> 

 </xsd:annotation> 

 </xsd:import> 

 <!-- Import CIS platform specification namespace - DEPRECATED --> 

 <xsd:import namespace="http://www.cisecurity.org/xccdf/platform/0.2.3" 

 schemaLocation="platform-0.2.3.xsd"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Import the CIS platform schema, which we use for 

 describing target IT platforms in the Benchmark. The 

 CIS platform schema was designed by David Waltermire. 

 Use of the CIS platform schema in XCCDF benchmarks is 

 deprecated. The CIS platform schema is included only for 

 backward compatibility with version 1.0. Use CPE instead. 

 </xsd:documentation> 

 </xsd:annotation> 

 </xsd:import> 

 <!-- Import XCCDF-P platform specification namespace - DEPRECATED --> 

 <xsd:import namespace="http://checklists.nist.gov/xccdf-p/1.1" 

 schemaLocation="xccdfp-1.1.xsd"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Import the XCCDF-P platform schema, which we use 

 for describing target IT platforms in the Benchmark. 

 The CIS platform schema was designed by Neal Ziring 

 using ideas and concepts developed by DISA, CIS, and 

 others. Use of XCCDF-P platform specification in 

 XCCDF benchmarks is deprecated. XCCDF-P is included 

 in this schema only for backward compatibility with 

 version 1.1 and 1.1.2. Use CPE instead. 

 </xsd:documentation> 

 </xsd:annotation> 

 </xsd:import> 

 <!-- Import CPE platform definition namespace --> 

 <xsd:import namespace="http://cpe.mitre.org/XMLSchema/cpe/1.0" 

 schemaLocation="cpe-1.0.xsd"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Import the Common Platform Enumeration XML schema, 

 which can be used for naming and describing target 

 IT platforms in the Benchmark. Every CPE Name is 

 a URI that begins with "cpe:". For more information 

 consult the document "Common Platform Enumeration (CPE) 

 - Name Format and Description" by Buttner, Wittbold, 

 and Ziring (2007). 

 Note that it is not necessary to define all the 

 CPE URIs used in a benchmark; common platforms will 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 be defined in a community concensus dictionary. Only 

 unusual or custom platforms typically will need to be 

 identified in a CPE cpe-list element in a benchmark. 

 </xsd:documentation> 

 </xsd:annotation> 

 </xsd:import> 

 <!-- ************************************************************** --> 

 <!-- ***************** Benchmark Element ************************ --> 

 <!-- ************************************************************** --> 

 <xsd:element name="Benchmark"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 The benchmark tag is the top level element representing a 

 complete security checklist, including descriptive text 

 and test items. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:complexType> 

 <xsd:sequence> 

 <xsd:element ref="cdf:status" 

 minOccurs="1" maxOccurs="unbounded"/> 

 <xsd:element name="title" type="cdf:textType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="description" type="cdf:htmlTextWithSubType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="notice" type="cdf:noticeType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="front-matter" type="cdf:htmlTextWithSubType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="rear-matter" type="cdf:htmlTextWithSubType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="reference" type="cdf:referenceType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="plain-text" type="cdf:plainTextType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:choice minOccurs="0" maxOccurs="1"> 

 <xsd:element ref="cisp:platform-definitions" 

 minOccurs="0" maxOccurs="1"/> 

 <xsd:element ref="cdfp:Platform-Specification" 

 minOccurs="0" maxOccurs="1"/> 

 <xsd:element ref="cpe:cpe-list" 

 minOccurs="0" maxOccurs="1"/> 

 </xsd:choice> 

 <xsd:element name="platform" type="cdf:URIidrefType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="version" type="cdf:versionType" 

 minOccurs="1" maxOccurs="1"/> 

 <xsd:element name="metadata" type="cdf:metadataType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element ref="cdf:model" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element ref="cdf:Profile" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element ref="cdf:Value" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:choice minOccurs="0" maxOccurs="unbounded"> 

 <xsd:element ref="cdf:Group"/> 

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 <xsd:element ref="cdf:Rule"/> 

 </xsd:choice> 

 <xsd:element ref="cdf:TestResult" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="signature" type="cdf:signatureType" 

 minOccurs="0" maxOccurs="1"/> 

 </xsd:sequence> 

 <xsd:attribute name="id" type="xsd:NCName" use="required"/> 

 <!-- the 'Id' attribute is needed for XML-Signature --> 

 <xsd:attribute name="Id" type="xsd:ID" use="optional"/> 

 <xsd:attribute name="resolved" type="xsd:boolean" 

 default="false" use="optional"/> 

 <xsd:attribute ref="xml:lang"/> 

 </xsd:complexType> 

 <xsd:key name="noticeIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 Legal notices must have unique id values. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath="cdf:notice"/> 

 <xsd:field xpath="@id"/> 

 </xsd:key> 

 <xsd:key name="itemIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 Items must have unique id values, and also they 

 must not collide 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath=".//cdf:Value|.//cdf:Group|.//cdf:Rule|./cdf:plaintext"/> 

 <xsd:field xpath="@id"/> 

 </xsd:key> 

 <xsd:key name="modelSystemKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 Model system attributes must be unique. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath="./cdf:model"/> 

 <xsd:field xpath="@system"/> 

 </xsd:key> 

 <xsd:key name="valueIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 Value item ids are special keys, need this for 

 the valueIdKeyRef and valueExtIdKeyRef keyrefs below. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath=".//cdf:Value"/> 

 <xsd:field xpath="@id"/> 

 </xsd:key> 

 <xsd:key name="groupIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 Group item ids are special keys, need this for 

 the groupIdKeyRef keyref below. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath=".//cdf:Group"/> 

 <xsd:field xpath="@id"/> 

 </xsd:key> 

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 <xsd:key name="ruleIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 Rule items have a unique key, we need 

 this for the ruleIdKeyRef keyref below. 

 (Rule key refs are used by rule-results.) 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath=".//cdf:Rule"/> 

 <xsd:field xpath="@id"/> 

 </xsd:key> 

 <xsd:key name="selectableItemIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 Group and Rule item ids are special keys, we 

 need this for the requiresIdKeyRef keyref below. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath=".//cdf:Group | .//cdf:Rule"/> 

 <xsd:field xpath="@id"/> 

 </xsd:key> 

 <xsd:key name="plainTextValueIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 Plaintext objects and Value objects each have 

 and id, and they must be unique and not overlap. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath="./cdf:plain-text | .//Value"/> 

 <xsd:field xpath="@id"/> 

 </xsd:key> 

 <xsd:key name="profileIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 Profile objects have a unique id, it is used 

 for extension, too. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath="./cdf:Profile"/> 

 <xsd:field xpath="@id"/> 

 </xsd:key> 

 <xsd:keyref name="valueExtIdKeyRef" refer="cdf:valueIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 An extends attribute on Value object 

 must reference an existing Value. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath=".//cdf:Value"/> 

 <xsd:field xpath="@extends"/> 

 </xsd:keyref> 

 <xsd:keyref name="groupExtIdKeyRef" refer="cdf:groupIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 An extends attribute on Group object 

 must reference an existing Group. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath=".//cdf:Group"/> 

 <xsd:field xpath="@extends"/> 

 </xsd:keyref> 

 <xsd:keyref name="ruleExtIdKeyRef" refer="cdf:ruleIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 An extends attribute on Rule object 

 must reference an existing Rule. 

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 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath=".//cdf:Rule"/> 

 <xsd:field xpath="@extends"/> 

 </xsd:keyref> 

 <xsd:keyref name="profileExtIdKeyRef" refer="cdf:profileIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 An extends attribute on Profile object 

 must reference an existing Profile. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath="./cdf:Profile"/> 

 <xsd:field xpath="@extends"/> 

 </xsd:keyref> 

 <xsd:keyref name="valueIdKeyRef" refer="cdf:valueIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 Check-export elements must reference existing values. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath=".//cdf:check/cdf:check-export"/> 

 <xsd:field xpath="@value-id"/> 

 </xsd:keyref> 

 <xsd:keyref name="subValueKeyRef" refer="cdf:plainTextValueIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 Sub elements must reference existing Value or 

 plain-text ids. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath=".//cdf:sub"/> 

 <xsd:field xpath="@value"/> 

 </xsd:keyref> 

 <xsd:keyref name="ruleIdKeyRef" 

 refer="cdf:ruleIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 The rule-result element idref must refer to an 

 existing Rule. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath="./cdf:TestResult/cdf:rule-result"/> 

 <xsd:field xpath="@idref"/> 

 </xsd:keyref> 

 <xsd:keyref name="profileIdKeyRef" 

 refer="cdf:profileIdKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 The requires a profile element in a TestResult 

 element to refer to an existing Profile 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath="./cdf:TestResult/profile"/> 

 <xsd:field xpath="@idref"/> 

 </xsd:keyref> 

 </xsd:element> 

 <xsd:complexType name="noticeType" mixed="true"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for legal notice element that has text 

 content and a unique id attribute. 

 </xsd:documentation> 

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 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:any namespace="http://www.w3.org/1999/xhtml" 

 minOccurs="0" maxOccurs="unbounded" 

 processContents="skip"/> 

 </xsd:sequence> 

 <xsd:attribute name="id" type="xsd:NCName"/> 

 <xsd:attribute ref="xml:base"/> 

 <xsd:attribute ref="xml:lang"/> 

 </xsd:complexType> 

 <xsd:complexType name="plainTextType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for a reusable text block, with an 

 unique id attribute. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:simpleContent> 

 <xsd:extension base="xsd:string"> 

 <xsd:attribute name="id" type="xsd:NCName" use="required"/> 

 </xsd:extension> 

 </xsd:simpleContent> 

 </xsd:complexType> 

 <xsd:complexType name="referenceType" mixed="true"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for a reference citation, an href URL attribute 

 (optional), with content of text or simple Dublin Core 

 elements. Elements of this type can also have an override 

 attribute to help manage inheritance. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:any namespace="http://purl.org/dc/elements/1.1/" 

 processContents="lax" 

 minOccurs="0" maxOccurs="unbounded"/> 

 </xsd:sequence> 

 <xsd:attribute name="href" type="xsd:anyURI"/> 

 <xsd:attribute name="override" type="xsd:boolean"/> 

 </xsd:complexType> 

 <xsd:complexType name="signatureType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 XML-Signature over the Benchmark; note that this will 

 always be an 'enveloped' signature, so the single 

 element child of this element should be dsig:Signature. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:any namespace="http://www.w3.org/2000/09/xmldsig#" 

 processContents="skip" minOccurs="1" maxOccurs="1"/> 

 </xsd:sequence> 

 </xsd:complexType> 

 <xsd:complexType name="metadataType"> 

 <xsd:annotation> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 <xsd:documentation xml:lang="en"> 

 Metadata for the Benchmark, should be Dublin Core 

 or some other well-specified and accepted metadata 

 format. If Dublin Core, then it will be a sequence 

 of simple Dublin Core elements. The NIST checklist 

 metadata should also be supported, although the 

 specification document is still in draft in NIST 

 special pub 800-70. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:choice minOccurs="1" maxOccurs="1"> 

 <xsd:any namespace="http://purl.org/dc/elements/1.1/" 

 minOccurs="1" maxOccurs="unbounded"/> 

 <xsd:any namespace="http://checklists.nist.gov/sccf/0.1" 

 processContents="skip" 

 minOccurs="1" maxOccurs="unbounded"/> 

 </xsd:choice> 

 </xsd:sequence> 

 </xsd:complexType> 

 <!-- ************************************************************** --> 

 <!-- ************* Global elements and types ******************** --> 

 <!-- ************************************************************** --> 

 <xsd:element name="status"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 The acceptance status of an Item with an optional date attribute 

 that signifies the date of the status change. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:complexType> 

 <xsd:simpleContent> 

 <xsd:extension base="cdf:statusType"> 

 <xsd:attribute name="date" type="xsd:date" 

 use="optional"/> 

 </xsd:extension> 

 </xsd:simpleContent> 

 </xsd:complexType> 

 </xsd:element> 

 <xsd:element name="model"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 A suggested scoring model for a Benchmark, also 

 encapsulating any parameters needed by the model. 

 Every model is designated with a URI, which 

 appears here as the system attribute. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:complexType> 

 <xsd:sequence> 

 <xsd:element name="param" type="cdf:paramType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 </xsd:sequence> 

 <xsd:attribute name="system" type="xsd:anyURI" 

 use="required"/> 

 </xsd:complexType> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 <xsd:key name="paramNameKey"> 

 <xsd:annotation><xsd:documentation xml:lang="en"> 

 Parameter names must be unique. 

 </xsd:documentation></xsd:annotation> 

 <xsd:selector xpath="./cdf:param"/> 

 <xsd:field xpath="@name"/> 

 </xsd:key> 

 </xsd:element> 

 <xsd:complexType name="paramType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for a scoring model parameter: a name and a 

 string value. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:simpleContent> 

 <xsd:extension base="xsd:string"> 

 <xsd:attribute name="name" type="xsd:NCName" use="required"/> 

 </xsd:extension> 

 </xsd:simpleContent> 

 </xsd:complexType> 

 <xsd:simpleType name="statusType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 The possible status codes for an Benchmark or Item to be 

 inherited from the parent element if it is not defined. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:restriction base="xsd:string"> 

 <xsd:enumeration value="accepted"/> 

 <xsd:enumeration value="deprecated"/> 

 <xsd:enumeration value="draft"/> 

 <xsd:enumeration value="incomplete"/> 

 <xsd:enumeration value="interim"/> 

 </xsd:restriction> 

 </xsd:simpleType> 

 <xsd:complexType name="versionType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for a version number, with a timestamp attribute 

 for when the version was made. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:simpleContent> 

 <xsd:extension base="xsd:string"> 

 <xsd:attribute name="time" type="xsd:dateTime" use="optional"/> 

 <xsd:attribute name="update" type="xsd:anyURI" use="optional"/> 

 </xsd:extension> 

 </xsd:simpleContent> 

 </xsd:complexType> 

 <!-- ************************************************************** --> 

 <!-- ******************** Text Types **************************** --> 

 <!-- ************************************************************** --> 

 <xsd:complexType name="textType"> 

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 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for a string with an xml:lang attribute. 

 Elements of this type can also have an override 

 attribute to help manage inheritance. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:simpleContent> 

 <xsd:extension base="xsd:string"> 

 <xsd:attribute ref="xml:lang"/> 

 <xsd:attribute name="override" type="xsd:boolean" 

 use="optional" default="0"/> 

 </xsd:extension> 

 </xsd:simpleContent> 

 </xsd:complexType> 

 <xsd:complexType name="htmlTextType" mixed="true"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for a string with XHTML elements and xml:lang attribute. 

 Elements of this type can also have an override 

 attribute to help manage inheritance. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:any namespace="http://www.w3.org/1999/xhtml" 

 minOccurs="0" maxOccurs="unbounded" 

 processContents="skip"/> 

 </xsd:sequence> 

 <xsd:attribute ref="xml:lang"/> 

 <xsd:attribute name="override" type="xsd:boolean" 

 use="optional" default="0"/> 

 </xsd:complexType> 

 <xsd:complexType name="htmlTextWithSubType" mixed="true"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for a string with embedded Value substitutions and 

 XHTML elements, and an xml:lang attribute. Elements of 

 this type can also have an override attribute to help 

 manage inheritance. [Note: this definition is rather 

 loose, it allows anything whatsoever to occur insides 

 XHTML tags inside here. Further, constraints of the XHTML 

 schema do not get checked! It might be possible to solve 

 this using XML Schema redefinition features.] 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:choice minOccurs="0" maxOccurs="unbounded"> 

 <xsd:element name="sub" type="cdf:idrefType"/> 

 <xsd:any namespace="http://www.w3.org/1999/xhtml" 

 processContents="skip"/> 

 </xsd:choice> 

 <xsd:attribute ref="xml:lang"/> 

 <xsd:attribute name="override" type="xsd:boolean" 

 use="optional" default="0"/> 

 </xsd:complexType> 

 <xsd:complexType name="profileNoteType" mixed="true"> 

 <xsd:annotation> 

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 <xsd:documentation xml:lang="en"> 

 Type for a string with embedded Value substitutions and 

 XHTML elements, an xml:lang attribute, and a profile-note tag. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:choice minOccurs="0" maxOccurs="unbounded"> 

 <xsd:element name="sub" type="cdf:idrefType"/> 

 <xsd:any namespace="http://www.w3.org/1999/xhtml" 

 processContents="skip"/> 

 </xsd:choice> 

 <xsd:attribute ref="xml:lang"/> 

 <xsd:attribute name="tag" type="xsd:NCName" use="required"/> 

 </xsd:complexType> 

 <xsd:complexType name="textWithSubType" mixed="true"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for a string with embedded Value substitutions 

 and XHTML elements, and an xml:lang attribute. 

 Elements of this type can also have an override 

 attribute to help manage inheritance. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:element name="sub" type="cdf:idrefType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 </xsd:sequence> 

 <xsd:attribute ref="xml:lang"/> 

 <xsd:attribute name="override" type="xsd:boolean" 

 use="optional" default="0"/> 

 </xsd:complexType> 

 <xsd:complexType name="idrefType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for elements that have no content, 

 just a mandatory id reference. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:attribute name="idref" type="xsd:NCName" use="required"/> 

 </xsd:complexType> 

 <xsd:complexType name="idrefListType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for elements that have no content, 

 just a space-separated list of id references. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:attribute name="idref" type="xsd:NMTOKENS" use="required"/> 

 </xsd:complexType> 

 <xsd:complexType name="overrideableIdrefType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for elements that have no content, 

 just a mandatory id reference, but also have 

 an override attribute for controlling inheritance. 

 </xsd:documentation> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 </xsd:annotation> 

 <xsd:complexContent> 

 <xsd:extension base="cdf:idrefType"> 

 <xsd:attribute name="override" type="xsd:boolean" 

 use="optional" default="0"/> 

 </xsd:extension> 

 </xsd:complexContent> 

 </xsd:complexType> 

 <xsd:complexType name="URIidrefType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for elements that have no content, 

 just a mandatory URI as an id. (This is mainly 

 for CPE URIs used as platform identifiers.) 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:attribute name="idref" type="xsd:anyURI" use="required"/> 

 </xsd:complexType> 

 <xsd:complexType name="overrideableURIidrefType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for elements that have no content, 

 just a mandatory URI reference, but also have 

 an override attribute for controlling inheritance. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:complexContent> 

 <xsd:extension base="cdf:URIidrefType"> 

 <xsd:attribute name="override" type="xsd:boolean" 

 use="optional" default="0"/> 

 </xsd:extension> 

 </xsd:complexContent> 

 </xsd:complexType> 

 <!-- ************************************************************** --> 

 <!-- **************** Item Element (Base Class) ****************** --> 

 <!-- ************************************************************** --> 

 <xsd:element name="Item" type="cdf:itemType" > 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type element type imposes constraints shared by all 

 Groups, Rules and Values. The itemType is abstract, so 

 the element Item can never appear in a valid XCCDF document. 

 </xsd:documentation> 

 </xsd:annotation> 

 </xsd:element> 

 <xsd:complexType name="itemType" abstract="1"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 This abstract item type represents the basic data shared by all 

 Groups, Rules and Values 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:element ref="cdf:status" 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="version" type="cdf:versionType" 

 minOccurs="0" maxOccurs="1"/> 

 <xsd:element name="title" type="cdf:textWithSubType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="description" type="cdf:htmlTextWithSubType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="warning" type="cdf:warningType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="question" type="cdf:textType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="reference" type="cdf:referenceType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 </xsd:sequence> 

 <xsd:attribute name="id" type="xsd:NCName" use="required"/> 

 <xsd:attribute name="abstract" type="xsd:boolean" 

 default="false" use="optional"/> 

 <xsd:attribute name="cluster-id" type="xsd:NCName" 

 use="optional"/> 

 <xsd:attribute name="extends" type="xsd:NCName" use="optional"/> 

 <xsd:attribute name="hidden" type="xsd:boolean" 

 default="false" use="optional"/> 

 <xsd:attribute name="prohibitChanges" type="xsd:boolean" 

 default="false" use="optional"/> 

 <xsd:attribute ref="xml:lang"/> 

 <xsd:attribute ref="xml:base"/> 

 <xsd:attribute name="Id" type="xsd:ID" use="optional"/> 

 </xsd:complexType> 

 <!-- ************************************************************** --> 

 <!-- ************ Selectable Item Type (Base Class) ************** --> 

 <!-- ************************************************************** --> 

 <xsd:complexType name="selectableItemType" abstract="true"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 This abstract item type represents the basic data shared by all 

 Groups and Rules. It extends the itemType given above. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:complexContent> 

 <xsd:extension base="cdf:itemType"> 

 <xsd:sequence> 

 <xsd:element name="rationale" 

 type="cdf:htmlTextWithSubType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="platform" 

 type="cdf:overrideableURIidrefType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="requires" type="cdf:idrefListType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="conflicts" type="cdf:idrefType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 </xsd:sequence> 

 <xsd:attribute name="selected" type="xsd:boolean" 

 default="true" use="optional"/> 

 <xsd:attribute name="weight" type="cdf:weightType" 

 default="1.0" use="optional"/> 

 </xsd:extension> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 </xsd:complexContent> 

 </xsd:complexType> 

 <!-- ************************************************************** --> 

 <!-- ********************** Group Element *********************** --> 

 <!-- ************************************************************** --> 

 <xsd:element name="Group" type="cdf:groupType"/> 

 <xsd:complexType name="groupType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for the Group element that represents a grouping of 

 Groups, Rules and Values. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:complexContent> 

 <xsd:extension base="cdf:selectableItemType"> 

 <xsd:sequence> 

 <xsd:element ref="cdf:Value" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:choice minOccurs="0" maxOccurs="unbounded"> 

 <xsd:element ref="cdf:Group"/> 

 <xsd:element ref="cdf:Rule"/> 

 </xsd:choice> 

 <xsd:element name="signature" type="cdf:signatureType" 

 minOccurs="0" maxOccurs="1"/> 

 </xsd:sequence> 

 </xsd:extension> 

 </xsd:complexContent> 

 </xsd:complexType> 

 <!-- ************************************************************** --> 

 <!-- ******************** Rule Element ************************** --> 

 <!-- ************************************************************** --> 

 <xsd:element name="Rule" type="cdf:ruleType"> 

 <xsd:unique name="ruleCheckSelectorKey"> 

 <xsd:selector xpath="./cdf:check"/> 

 <xsd:field xpath="@selector"/> 

 <xsd:field xpath="@system"/> 

 </xsd:unique> 

 <xsd:unique name="ruleCheckIdKey"> 

 <xsd:selector xpath=".//cdf:check"/> 

 <xsd:field xpath="@id"/> 

 </xsd:unique> 

 </xsd:element> 

 <xsd:complexType name="ruleType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for the Rule element that represents a 

 specific benchmark test. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:complexContent> 

 <xsd:extension base="cdf:selectableItemType"> 

 <xsd:sequence> 

 <xsd:element name="ident" type="cdf:identType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="profile-note" minOccurs="0" 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 type="cdf:profileNoteType" 

 maxOccurs="unbounded"/> 

 <xsd:element name="fixtext" type="cdf:fixTextType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="fix" type="cdf:fixType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:choice> 

 <xsd:element name="check" type="cdf:checkType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="complex-check" minOccurs="0" 

 type="cdf:complexCheckType" maxOccurs="1"/> 

 </xsd:choice> 

 <xsd:element name="signature" type="cdf:signatureType" 

 minOccurs="0" maxOccurs="1"/> 

 </xsd:sequence> 

 <xsd:attribute name="role" type="cdf:roleEnumType" 

 use="optional" default="full"/> 

 <xsd:attribute name="severity" type="cdf:severityEnumType" 

 default="unknown" use="optional"/> 

 <xsd:attribute name="multiple" type="xsd:boolean" 

 use="optional"/> 

 </xsd:extension> 

 </xsd:complexContent> 

 </xsd:complexType> 

 <!-- ************************************************************** --> 

 <!-- ***************** Rule-related Types ************************ --> 

 <!-- ************************************************************** --> 

 <xsd:complexType name="identType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for a long-term globally meaningful identifier, 

 consisting of a string (ID) and a URI of the naming 

 scheme within which the name is meaningful. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:simpleContent> 

 <xsd:extension base="xsd:string"> 

 <xsd:attribute name="system" type="xsd:anyURI" use="required"/> 

 </xsd:extension> 

 </xsd:simpleContent> 

 </xsd:complexType> 

 <xsd:complexType name="warningType" mixed="true"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for the warning element under the Rule 

 object, a rich text string with substitutions 

 allowed, plus an attribute for the kind of warning. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:complexContent> 

 <xsd:extension base="cdf:htmlTextWithSubType"> 

 <xsd:attribute name="category" 

 type="cdf:warningCategoryEnumType" 

 use="optional" default="general"/> 

 </xsd:extension> 

 </xsd:complexContent> 

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 </xsd:complexType> 

 <xsd:simpleType name="warningCategoryEnumType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Allowed warning category keywords for the warning 

 element. The allowed categories are: 

 general=broad or general-purpose warning (default 

 for compatibility for XCCDF 1.0) 

 functionality=warning about possible impacts to 

 functionality or operational features 

 performance=warning about changes to target 

 system performance or throughput 

 hardware=warning about hardware restrictions or 

 possible impacts to hardware 

 legal=warning about legal implications 

 regulatory=warning about regulatory obligations 

 or compliance implications 

 management=warning about impacts to the mgmt 

 or administration of the target system 

 audit=warning about impacts to audit or logging 

 dependency=warning about dependencies between 

 this Rule and other parts of the target 

 system, or version dependencies. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:restriction base="xsd:string"> 

 <xsd:enumeration value="general"/> 

 <xsd:enumeration value="functionality"/> 

 <xsd:enumeration value="performance"/> 

 <xsd:enumeration value="hardware"/> 

 <xsd:enumeration value="legal"/> 

 <xsd:enumeration value="regulatory"/> 

 <xsd:enumeration value="management"/> 

 <xsd:enumeration value="audit"/> 

 <xsd:enumeration value="dependency"/> 

 </xsd:restriction> 

 </xsd:simpleType> 

 <xsd:complexType name="fixTextType" mixed="true"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for the fixText element that represents 

 a rich text string, with substitutions allowed, and 

 a series of attributes that qualify the fix. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:complexContent> 

 <xsd:extension base="cdf:htmlTextWithSubType"> 

 <xsd:attribute name="fixref" type="xsd:NCName" 

 use="optional"/> 

 <xsd:attribute name="reboot" type="xsd:boolean" 

 use="optional" default="0"/> 

 <xsd:attribute name="strategy" type="cdf:fixStrategyEnumType" 

 use="optional" default="unknown"/> 

 <xsd:attribute name="disruption" type="cdf:ratingEnumType" 

 use="optional" default="unknown"/> 

 <xsd:attribute name="complexity" type="cdf:ratingEnumType" 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 use="optional" default="unknown"/> 

 </xsd:extension> 

 </xsd:complexContent> 

 </xsd:complexType> 

 <xsd:complexType name="fixType" mixed="true"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for a string with embedded Value and instance 

 substitutions and an optional platform id ref attribute, but 

 no embedded XHTML markup. 

 The platform attribute should refer to a platform-definition 

 element in the platform-definitions child of the Benchmark. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:choice minOccurs="0" maxOccurs="unbounded"> 

 <xsd:element name="sub" type="cdf:idrefType"/> 

 <xsd:element name="instance" type="cdf:instanceFixType"/> 

 </xsd:choice> 

 <xsd:attribute name="id" type="xsd:NCName" use="optional"/> 

 <xsd:attribute name="reboot" type="xsd:boolean" 

 use="optional" default="0"/> 

 <xsd:attribute name="strategy" type="cdf:fixStrategyEnumType" 

 use="optional" default="unknown"/> 

 <xsd:attribute name="disruption" type="cdf:ratingEnumType" 

 use="optional" default="unknown"/> 

 <xsd:attribute name="complexity" type="cdf:ratingEnumType" 

 use="optional" default="unknown"/> 

 <xsd:attribute name="system" type="xsd:anyURI" use="optional"/> 

 <xsd:attribute name="platform" type="xsd:anyURI" use="optional"/> 

 </xsd:complexType> 

 <xsd:simpleType name="fixStrategyEnumType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Allowed strategy keyword values for a Rule fix or 

 fixtext. The allowed values are: 

 unknown= strategy not defined (default for forward 

 compatibility for XCCDF 1.0) 

 configure=adjust target config or settings 

 patch=apply a patch, hotfix, or update 

 policy=remediation by changing policies/procedures 

 disable=turn off or deinstall something 

 enable=turn on or install something 

 restrict=adjust permissions or ACLs 

 update=install upgrade or update the system 

 combination=combo of two or more of the above 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:restriction base="xsd:string"> 

 <xsd:enumeration value="unknown"/> 

 <xsd:enumeration value="configure"/> 

 <xsd:enumeration value="combination"/> 

 <xsd:enumeration value="disable"/> 

 <xsd:enumeration value="enable"/> 

 <xsd:enumeration value="patch"/> 

 <xsd:enumeration value="policy"/> 

 <xsd:enumeration value="restrict"/> 

 <xsd:enumeration value="update"/> 

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 </xsd:restriction> 

 </xsd:simpleType> 

 <xsd:simpleType name="ratingEnumType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Allowed rating values values for a Rule fix 

 or fixtext: disruption, complexity, and maybe overhead. 

 The possible values are: 

 unknown= rating unknown or 

 impossible to estimate (default for 

 forward compatibility for XCCDF 1.0) 

 low = little or no potential for disruption, 

 very modest complexity 

 medium= some chance of minor disruption, 

 substantial complexity 

 high = likely to cause serious disruption, 

 extremely complex 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:restriction base="xsd:string"> 

 <xsd:enumeration value="unknown"/> 

 <xsd:enumeration value="low"/> 

 <xsd:enumeration value="medium"/> 

 <xsd:enumeration value="high"/> 

 </xsd:restriction> 

 </xsd:simpleType> 

 <xsd:complexType name="instanceFixType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for an instance element in a fix element. The 

 instance element inside a fix element designates a 

 spot where the name of the instance should be 

 substituted into the fix template to generate the 

 final fix data. The instance element in this usage 

 has one optional attribute: context. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:attribute name="context" type="xsd:string" 

 default="undefined" use="optional"/> 

 </xsd:complexType> 

 <xsd:complexType name="complexCheckType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 The type for an element that can contains a boolean 

 expression based on checks. This element can have only 

 complex-check and check elements as children. It has two 

 attributes: operator and negate. The operator attribute 

 can have values "OR" or "AND", and the negate attribute is 

 boolean. See the specification document for truth tables 

 for the operators and negations. Note: complex-check is 

 defined in this way for conceptual equivalence with OVAL. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:choice minOccurs="1" maxOccurs="unbounded"> 

 <xsd:element name="check" type="cdf:checkType"/> 

 <xsd:element name="complex-check" type="cdf:complexCheckType"/> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 </xsd:choice> 

 <xsd:attribute name="operator" 

 type="cdf:ccOperatorEnumType" use="required"/> 

 <xsd:attribute name="negate" default="0" 

 type="xsd:boolean" use="optional"/> 

 </xsd:complexType> 

 <xsd:simpleType name="ccOperatorEnumType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 The type for the allowed operator names for the 

 complex-check operator attribute. For now, we just 

 allow boolean AND and OR as operators. (The 

 complex-check has a separate mechanism for inversion.) 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:restriction base="xsd:string"> 

 <xsd:enumeration value="OR"/> 

 <xsd:enumeration value="AND"/> 

 </xsd:restriction> 

 </xsd:simpleType> 

 <xsd:complexType name="checkType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for the check element, a checking system 

 specification URI, and XML content. The content of the 

 check element is: zero or more check-export elements, 

 zero or more check-content-ref elements, and finally 

 an optional check-content element. An content-less 

 check element isn't legal, but XSD cannot express that! 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:element name="check-export" type="cdf:checkExportType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="check-content-ref" 

 minOccurs="0" maxOccurs="unbounded" 

 type="cdf:checkContentRefType"/> 

 <xsd:element name="check-content" 

 minOccurs="0" maxOccurs="1" 

 type="cdf:checkContentType"/> 

 </xsd:sequence> 

 <xsd:attribute name="system" type="xsd:anyURI" use="required"/> 

 <xsd:attribute name="id" type="xsd:NCName" use="optional"/> 

 <xsd:attribute name="selector" default="" 

 type="xsd:string" use="optional"/> 

 <xsd:attribute ref="xml:base"/> 

 </xsd:complexType> 

 <xsd:complexType name="checkExportType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for the check-export element, which specifies 

 a mapping between an XCCDF internal Value id and a 

 value name to be used by the checking system or processor. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:attribute name="value-id" type="xsd:NCName" use="required"/> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 <xsd:attribute name="export-name" type="xsd:string" use="required"/> 

 </xsd:complexType> 

 <xsd:complexType name="checkContentRefType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for the check-content-ref element, which 

 points to the code for a detached check in another file. 

 This element has no body, just a couple of attributes: 

 href and name. The name is optional, if it does not appear 

 then this reference is to the entire other document. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:attribute name="href" type="xsd:anyURI" use="required"/> 

 <xsd:attribute name="name" type="xsd:string"/> 

 </xsd:complexType> 

 <xsd:complexType name="checkContentType" mixed="true"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for the check-content element, which holds 

 the actual code of an enveloped check in some other 

 (non-XCCDF) language. This element can hold almost 

 anything; XCCDF tools do not process its content directly. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:choice minOccurs="0" maxOccurs="unbounded"> 

 <xsd:any namespace="##other" processContents="skip"/> 

 </xsd:choice> 

 </xsd:complexType> 

 <xsd:simpleType name="weightType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for a Rule's weight, a non-negative real number. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:restriction base="xsd:decimal"> 

 <xsd:minInclusive value="0.0"/> 

 <xsd:totalDigits value="3"/> 

 </xsd:restriction> 

 </xsd:simpleType> 

 <!-- ************************************************************** --> 

 <!-- ******************* Value Element ************************** --> 

 <!-- ************************************************************** --> 

 <xsd:element name="Value" type="cdf:valueType"> 

 <xsd:unique name="valueSelectorKey"> 

 <xsd:selector xpath="./cdf:value"/> 

 <xsd:field xpath="@selector"/> 

 </xsd:unique> 

 <xsd:unique name="defaultSelectorKey"> 

 <xsd:selector xpath="./cdf:default"/> 

 <xsd:field xpath="@selector"/> 

 </xsd:unique> 

 </xsd:element> 

 <xsd:complexType name="valueType"> 

 <xsd:annotation> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 <xsd:documentation xml:lang="en"> 

 Data type for the Value element, which represents 

 a tailorable string, numeric, or boolean value in 

 the Benchmark. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:complexContent> 

 <xsd:extension base="cdf:itemType"> 

 <xsd:sequence> 

 <xsd:element name="value" type="cdf:selStringType" 

 minOccurs="1" maxOccurs="unbounded"/> 

 <xsd:element name="default" type="cdf:selStringType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="match" type="cdf:selStringType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="lower-bound" type="cdf:selNumType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="upper-bound" type="cdf:selNumType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="choices" type="cdf:selChoicesType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="source" type="cdf:uriRefType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="signature" type="cdf:signatureType" 

 minOccurs="0" maxOccurs="1"/> 

 </xsd:sequence> 

 <xsd:attribute name="type" type="cdf:valueTypeType" 

 default="string" use="optional"/> 

 <xsd:attribute name="operator" type="cdf:valueOperatorType" 

 default="equals" use="optional"/> 

 <xsd:attribute name="interactive" type="xsd:boolean" 

 default="0" use="optional"/> 

 <xsd:attribute name="interfaceHint" use="optional" 

 type="cdf:interfaceHintType"/> 

 </xsd:extension> 

 </xsd:complexContent> 

 </xsd:complexType> 

 <!-- ************************************************************** --> 

 <!-- *************** Value-related Types ************************ --> 

 <!-- ************************************************************** --> 

 <xsd:complexType name="selChoicesType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 The choice element specifies a list of legal or suggested 

 choices for a Value object. It holds one or more choice 

 elements, a mustMatch attribute, and a selector attribute. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:element name="choice" type="xsd:string" 

 minOccurs="1" maxOccurs="unbounded"/> 

 </xsd:sequence> 

 <xsd:attribute name="mustMatch" type="xsd:boolean" use="optional"/> 

 <xsd:attribute name="selector" default="" 

 type="xsd:string" use="optional"/> 

 </xsd:complexType> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 <xsd:complexType name="selStringType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 This type is for an element that has string content 

 and a selector attribute. It is used for some of 

 the child elements of Value. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:simpleContent> 

 <xsd:extension base="xsd:string"> 

 <xsd:attribute name="selector" default="" 

 type="xsd:string" use="optional"/> 

 </xsd:extension> 

 </xsd:simpleContent> 

 </xsd:complexType> 

 <xsd:complexType name="selNumType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 This type is for an element that has numeric content 

 and a selector attribute. It is used for two of 

 the child elements of Value. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:simpleContent> 

 <xsd:extension base="xsd:decimal"> 

 <xsd:attribute name="selector" default="" 

 type="xsd:string" use="optional"/> 

 </xsd:extension> 

 </xsd:simpleContent> 

 </xsd:complexType> 

 <xsd:complexType name="uriRefType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Data type for elements that have no content, 

 just a mandatory URI. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:attribute name="uri" type="xsd:anyURI" use="required"/> 

 </xsd:complexType> 

 <xsd:simpleType name="valueTypeType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Allowed data types for Values, just string, numeric, 

 and true/false. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:restriction base="xsd:string"> 

 <xsd:enumeration value="number"/> 

 <xsd:enumeration value="string"/> 

 <xsd:enumeration value="boolean"/> 

 </xsd:restriction> 

 </xsd:simpleType> 

 <xsd:simpleType name="valueOperatorType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 Allowed operators for Values. Note that most of 

 these are valid only for numeric data, but the 

 schema doesn't enforce that. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:restriction base="xsd:string"> 

 <xsd:enumeration value="equals" /> 

 <xsd:enumeration value="not equal" /> 

 <xsd:enumeration value="greater than" /> 

 <xsd:enumeration value="less than" /> 

 <xsd:enumeration value="greater than or equal" /> 

 <xsd:enumeration value="less than or equal" /> 

 <xsd:enumeration value="pattern match" /> 

 </xsd:restriction> 

 </xsd:simpleType> 

 <xsd:simpleType name="interfaceHintType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Allowed interface hint values. When an interfaceHint 

 appears on the Value, it provides a suggestion to a 

 tailoring or benchmarking tool about how to present the 

 UI for adjusting a Value. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:restriction base="xsd:string"> 

 <xsd:enumeration value="choice"/> 

 <xsd:enumeration value="textline"/> 

 <xsd:enumeration value="text"/> 

 <xsd:enumeration value="date"/> 

 <xsd:enumeration value="datetime"/> 

 </xsd:restriction> 

 </xsd:simpleType> 

 <!-- ************************************************************** --> 

 <!-- ******************* Profile Element ************************ --> 

 <!-- ************************************************************** --> 

 <xsd:element name="Profile" type="cdf:profileType"> 

 <!-- selector key constraints --> 

 <xsd:unique name="itemSelectKey"> 

 <xsd:selector xpath="./cdf:select"/> 

 <xsd:field xpath="@idref"/> 

 </xsd:unique> 

 <xsd:unique name="refineRuleKey"> 

 <xsd:selector xpath="./cdf:refine-rule"/> 

 <xsd:field xpath="@idref"/> 

 </xsd:unique> 

 <xsd:unique name="refineValueKey"> 

 <xsd:selector xpath="./cdf:refine-value"/> 

 <xsd:field xpath="@idref"/> 

 </xsd:unique> 

 <xsd:unique name="setValueKey"> 

 <xsd:selector xpath="./cdf:set-value"/> 

 <xsd:field xpath="@idref"/> 

 </xsd:unique> 

 </xsd:element> 

 <xsd:complexType name="profileType"> 

 <xsd:annotation> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 <xsd:documentation xml:lang="en"> 

 Data type for the Profile element, which holds a 

 specific tailoring of the Benchmark. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:element ref="cdf:status" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="version" type="cdf:versionType" 

 minOccurs="0" maxOccurs="1"/> 

 <xsd:element name="title" type="cdf:textWithSubType" 

 minOccurs="1" maxOccurs="unbounded"/> 

 <xsd:element name="description" type="cdf:htmlTextWithSubType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="reference" type="cdf:referenceType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="platform" type="cdf:URIidrefType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="select" type="cdf:profileSelectType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="set-value" type="cdf:profileSetValueType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="refine-value" 

 type="cdf:profileRefineValueType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="refine-rule" 

 type="cdf:profileRefineRuleType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="signature" type="cdf:signatureType" 

 minOccurs="0" maxOccurs="1"/> 

 </xsd:sequence> 

 <xsd:attribute name="id" type="xsd:NCName" use="required"/> 

 <xsd:attribute name="prohibitChanges" type="xsd:boolean" 

 default="false" use="optional"/> 

 <xsd:attribute name="abstract" type="xsd:boolean" 

 default="false" use="optional"/> 

 <xsd:attribute name="note-tag" type="xsd:NCName" 

 use="optional"/> 

 <xsd:attribute name="extends" type="xsd:NCName" use="optional"/> 

 <xsd:attribute ref="xml:base"/> 

 <xsd:attribute name="Id" type="xsd:ID" use="optional"/> 

 </xsd:complexType> 

 <!-- ************************************************************** --> 

 <!-- *************** Profile-related Types *********************** --> 

 <!-- ************************************************************** --> 

 <xsd:complexType name="profileSelectType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for the select element in a Profile; all it has are two 

 attributes, no content. The two attributes are idref which 

 refers to a Group or Rule, and selected which is boolean. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:attribute name="idref" type="xsd:NCName" use="required"/> 

 <xsd:attribute name="selected" type="xsd:boolean" use="required"/> 

 </xsd:complexType> 

 <xsd:complexType name="profileSetValueType"> 

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 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for the set-value element in a Profile; it 

 has one attribute and string content. The 

 attribute is 'idref' which refers to a Value. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:simpleContent> 

 <xsd:extension base="xsd:string"> 

 <xsd:attribute name="idref" type="xsd:NCName"/> 

 </xsd:extension> 

 </xsd:simpleContent> 

 </xsd:complexType> 

 <xsd:complexType name="profileRefineValueType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for the refine-value element in a Profile; all it has 

 are three attributes, no content. The three attributes are 

 'idref' which refers to a Value, 'selector' which designates 

 certain element children of the Value, and 'operator' which 

 can override the operator attribute of the Value. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:attribute name="idref" 

 type="xsd:NCName" use="required"/> 

 <xsd:attribute name="selector" 

 type="xsd:string" use="optional"/> 

 <xsd:attribute name="operator" 

 type="cdf:valueOperatorType" use="optional"/> 

 </xsd:complexType> 

 <xsd:complexType name="profileRefineRuleType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for the refine-rule element in a Profile; all it has 

 are four attributes, no content. The main attribute is 

 'idref' which refers to a Rule, and three attributes that 

 allow the Profile author to adjust aspects of how a Rule is 

 processed during a benchmark run: weight, severity, role. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:attribute name="idref" type="xsd:NCName" use="required"/> 

 <xsd:attribute name="weight" type="cdf:weightType" use="optional"/> 

 <xsd:attribute name="selector" 

 type="xsd:string" use="optional"/> 

 <xsd:attribute name="severity" 

 type="cdf:severityEnumType" use="optional"/> 

 <xsd:attribute name="role" 

 type="cdf:roleEnumType" use="optional"/> 

 </xsd:complexType> 

 <!-- ************************************************************** --> 

 <!-- ******************* TestResult Element ********************* --> 

 <!-- ************************************************************** --> 

 <xsd:element name="TestResult" type="cdf:testResultType"/> 

 <xsd:complexType name="testResultType"> 

 <xsd:annotation> 

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 <xsd:documentation xml:lang="en"> 

 Data type for the TestResult element, which holds the 

 results of one application of the Benchmark. The optional 

 test-system attribute gives the name of the benchmarking tool. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:element name="benchmark" minOccurs="0" maxOccurs="1"> 

 <xsd:complexType> 

 <xsd:attribute name="href" type="xsd:anyURI" use="required"/> 

 </xsd:complexType> 

 </xsd:element> 

 <xsd:element name="title" type="cdf:textType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="remark" type="cdf:textType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="profile" type="cdf:idrefType" 

 minOccurs="0" maxOccurs="1"/> 

 <xsd:element name="target" type="xsd:string" 

 minOccurs="1" maxOccurs="unbounded"/> 

 <xsd:element name="target-address" type="xsd:string" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="target-facts" type="cdf:targetFactsType" 

 minOccurs="0" maxOccurs="1"/> 

 <xsd:element name="platform" type="cdf:URIidrefType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="set-value" type="cdf:profileSetValueType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="rule-result" type="cdf:ruleResultType" 

 minOccurs="0" maxOccurs="unbounded"> 

 <!-- Each context name in an instance must be unique. --> 

 <xsd:key name="instanceContextKey"> 

 <xsd:selector xpath="cdf:instance"/> 

 <xsd:field xpath="@context"/> 

 </xsd:key> 

 <!-- parentContext must refer to valid sibling context --> 

 <xsd:keyref name="parentKeyRef" refer="cdf:instanceContextKey"> 

 <xsd:selector xpath="./cdf:instance"/> 

 <xsd:field xpath="@parentContext"/> 

 </xsd:keyref> 

 </xsd:element> 

 <xsd:element name="score" type="cdf:scoreType" 

 minOccurs="1" maxOccurs="unbounded"/> 

 <xsd:element name="signature" type="cdf:signatureType" 

 minOccurs="0" maxOccurs="1"/> 

 </xsd:sequence> 

 <xsd:attribute name="id" type="xsd:NCName" use="required"/> 

 <xsd:attribute name="start-time" type="xsd:dateTime" use="optional"/> 

 <xsd:attribute name="end-time" type="xsd:dateTime" use="required"/> 

 <xsd:attribute name="test-system" type="xsd:string" use="optional"/> 

 <xsd:attribute name="version" type="xsd:string" use="optional"/> 

 <xsd:attribute name="Id" type="xsd:ID" use="optional"/> 

 </xsd:complexType> 

 <xsd:complexType name="scoreType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for a score value in a TestResult, the content is a 

 real number and the element can have two optional attributes. 

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 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:simpleContent> 

 <xsd:extension base="xsd:decimal"> 

 <xsd:attribute name="system" type="xsd:anyURI" 

 use="optional"/> 

 <xsd:attribute name="maximum" type="xsd:decimal" 

 use="optional"/> 

 </xsd:extension> 

 </xsd:simpleContent> 

 </xsd:complexType> 

 

 <xsd:complexType name="targetFactsType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 This element holds a list of facts about the target system 

 or platform. Each fact is an element of type factType. 

 Each fact must have a name, but duplicate names are allowed. 

 (For example, if you had a fact about MAC addresses, and the 

 target system had three NICs, then you'd need three 

 instance of the "urn:xccdf:fact:ethernet:MAC" fact.) 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:element name="fact" type="cdf:factType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 </xsd:sequence> 

 </xsd:complexType> 

 <xsd:complexType name="factType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Element type for a fact about a target system: a 

 name-value pair with a type. The content of the element 

 is the value, the type attribute gives the type. This 

 is an area where XML schema is weak: we can't make the 

 schema validator check that the content matches the type. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:simpleContent> 

 <xsd:extension base="xsd:string"> 

 <xsd:attribute name="name" type="xsd:anyURI" use="required"/> 

 <xsd:attribute name="type" type="cdf:valueTypeType" 

 default="boolean" use="optional"/> 

 </xsd:extension> 

 </xsd:simpleContent> 

 </xsd:complexType> 

 <xsd:complexType name="ruleResultType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 This element holds all the information about the application of one 

 rule to a target. It may only appear as part of a TestResult object. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:element name="result" type="cdf:resultEnumType" 

 minOccurs="1" maxOccurs="1"/> 

 <xsd:element name="override" type="cdf:overrideType" 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="ident" type="cdf:identType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="message" type="cdf:messageType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="instance" type="cdf:instanceResultType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <xsd:element name="fix" type="cdf:fixType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 <!-- will we need a new restricted form for this? --> 

 <xsd:element name="check" type="cdf:checkType" 

 minOccurs="0" maxOccurs="unbounded"/> 

 </xsd:sequence> 

 <xsd:attribute name="idref" type="xsd:NCName" use="required"/> 

 <xsd:attribute name="role" type="cdf:roleEnumType" use="optional"/> 

 <xsd:attribute name="severity" type="cdf:severityEnumType" 

 use="optional"/> 

 <xsd:attribute name="time" type="xsd:dateTime" use="optional"/> 

 <xsd:attribute name="version" type="xsd:string" use="optional"/> 

 </xsd:complexType> 

 <xsd:complexType name="instanceResultType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for an instance element in a rule-result. 

 The content is a string, but the element may 

 also have two attribute: context and parentContext. 

 This type records the details of the target system 

 instance for multiply instantiated rules. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:simpleContent> 

 <xsd:extension base="xsd:string"> 

 <xsd:attribute name="context" default="undefined" 

 type="xsd:string" use="optional"/> 

 <xsd:attribute name="parentContext" type="xsd:string" use="optional"/> 

 </xsd:extension> 

 </xsd:simpleContent> 

 </xsd:complexType> 

 <xsd:complexType name="overrideType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for an override block in a rule-result. 

 It contains five mandatory parts: time, authority, 

 old-result, new-result, and remark. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:sequence> 

 <xsd:element name="old-result" type="cdf:resultEnumType" 

 minOccurs="1" maxOccurs="1"/> 

 <xsd:element name="new-result" type="cdf:resultEnumType" 

 minOccurs="1" maxOccurs="1"/> 

 <xsd:element name="remark" type="cdf:textType" 

 minOccurs="1" maxOccurs="1"/> 

 </xsd:sequence> 

 <xsd:attribute name="time" type="xsd:dateTime" use="required"/> 

 <xsd:attribute name="authority" type="xsd:string" use="required"/> 

 </xsd:complexType> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 <xsd:complexType name="messageType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Type for a message generated by the checking 

 engine or XCCDF tool during benchmark testing. 

 Content is string plus required severity attribute. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:simpleContent> 

 <xsd:extension base="xsd:string"> 

 <xsd:attribute name="severity" type="cdf:msgSevEnumType" 

 use="required"/> 

 </xsd:extension> 

 </xsd:simpleContent> 

 </xsd:complexType> 

 <xsd:simpleType name="msgSevEnumType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Allowed values for message severity. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:restriction base="xsd:string"> 

 <xsd:enumeration value="error"/> 

 <xsd:enumeration value="warning"/> 

 <xsd:enumeration value="info"/> 

 </xsd:restriction> 

 </xsd:simpleType> 

 <xsd:simpleType name="resultEnumType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Allowed result indicators for a test, several possibilities: 

 pass= the test passed, target complies w/ benchmark 

 fail= the test failed, target does not comply 

 error= an error occurred and test could not complete, 

 or the test does not apply to this plaform 

 unknown= could not tell what happened, results 

 with this status are not to be scored 

 notapplicable=Rule did not apply to test target 

 fixed=rule failed, but was later fixed (score as pass) 

 notchecked=Rule did not cause any evaluation by 

 the checking engine (role of "unchecked") 

 notselected=Rule was not selected in the Benchmark, 

 and therefore was not checked (selected="0") 

 informational=Rule was evaluated by the checking 

 engine, but isn't to be scored (role of "unscored") 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:restriction base="xsd:string"> 

 <xsd:enumeration value="pass"/> 

 <xsd:enumeration value="fail"/> 

 <xsd:enumeration value="error"/> 

 <xsd:enumeration value="unknown"/> 

 <xsd:enumeration value="notapplicable"/> 

 <xsd:enumeration value="notchecked"/> 

 <xsd:enumeration value="notselected"/> 

 <xsd:enumeration value="informational"/> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 <xsd:enumeration value="fixed"/> 

 </xsd:restriction> 

 </xsd:simpleType> 

 <xsd:simpleType name="severityEnumType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Allowed severity values for a Rule. 

 there are several possible values: 

 unknown= severity not defined (default, for compatibility with XCCDF 1.0) 

 info = rule is informational only, failing the rule does not 

 imply failure to conform to guidance of the benchmark. 

 (usually would also have a weight of 0) 

 low = not a serious problem 

 medium= fairly serious problem 

 high = a grave or critical problem 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:restriction base="xsd:string"> 

 <xsd:enumeration value="unknown"/> 

 <xsd:enumeration value="info"/> 

 <xsd:enumeration value="low"/> 

 <xsd:enumeration value="medium"/> 

 <xsd:enumeration value="high"/> 

 </xsd:restriction> 

 </xsd:simpleType> 

 <xsd:simpleType name="roleEnumType"> 

 <xsd:annotation> 

 <xsd:documentation xml:lang="en"> 

 Allowed checking and scoring roles for a Rule. 

 There are several possible values: 

 full = if the rule is selected, then check it and let the 

 result contribute to the score and appear in reports 

 (default, for compatibility for XCCDF 1.0). 

 unscored = check the rule, and include the results in 

 any report, but do not include the result in 

 score computations (in the default scoring model 

 the same effect can be achieved with weight=0) 

 unchecked = don't check the rule, just force the result 

 status to 'unknown'. Include the rule's 

 information in any reports. 

 </xsd:documentation> 

 </xsd:annotation> 

 <xsd:restriction base="xsd:string"> 

 <xsd:enumeration value="full"/> 

 <xsd:enumeration value="unscored"/> 

 <xsd:enumeration value="unchecked"/> 

 </xsd:restriction> 

 </xsd:simpleType> 

</xsd:schema> 

Testing 

The XCCDF 1.1 schema has been checked for syntax and tested with the Apache 

Xerces 2.6 schema-validating parser and with Altova XMLSpytm 2005 release 3. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

7. Appendix B – Sample Benchmark File 

The sample below illustrates some of the concepts of XCCDF. It gives a few simple rules about 

configuration of a Cisco IOS router, based on material from the publicly available NSA Router 

Security Configuration Guide. 

<?xml version="1.0" encoding="UTF-8"?> 

<cdf:Benchmark id="ios-test-1" resolved="0" xml:lang="en" 

 xmlns:cdf="http://checklists.nist.gov/xccdf/1.1" 

 xmlns:cpe="http://cpe.mitre.org/XMLSchema/cpe/1.0" 

 xmlns:dc="http://purl.org/dc/elements/1.1/" 

 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 

 xmlns:htm="http://www.w3.org/1999/xhtml" 

 xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" 

 xsi:schemaLocation="http://checklists.nist.gov/xccdf/1.1 xccdf-1.1.xsd 

http://cpe.mitre.org/XMLSchema/cpe/1.0 cpe-1.0.xsd"> 

 <cdf:status date="2006-12-12">draft</cdf:status> 

 <cdf:title>XCCDF Sample for Cisco IOS</cdf:title> 

 <cdf:description> 

 This document defines a small set of rules for securing Cisco 

 IOS routers. The set of rules constitute a <htm:i>benchmark</htm:i>. 

 A benchmark usually represents an industry consensus of best 

 practices. It lists steps to be taken as well as rationale for 

 them. This example benchmark is merely a small subset of the 

 rules that would be necessary for securing an IOS router. 

 </cdf:description> 

 <cdf:notice id="Sample-Terms-Of-Use" xml:lang="en"> 

 This document may be copied and used subject to the 

 subject to the NIST terms of use 

 (http://www.nist.gov/public_affairs/disclaim.htm) 

 and the NSA Legal Notices 

 (http://www.nsa.gov/notices/notic00004.cfm?Address=/). 

 </cdf:notice> 

 <cdf:front-matter> 

 <htm:p> 

 This benchmark assumes that you are running IOS 11.3 or later. 

 </htm:p> 

 </cdf:front-matter> 

 <cdf:reference href="http://www.nsa.gov/ia/"> 

 NSA Router Security Configuration Guide, Version 1.1c 

 </cdf:reference> 

 <cdf:reference> 

 <dc:title>Hardening Cisco Routers</dc:title> 

 <dc:creator>Thomas Akin</dc:creator> 

 <dc:publisher>O'Reilly and Associates</dc:publisher> 

 <dc:identifier>http://www.ora.com/</dc:identifier> 

 </cdf:reference> 

 <cdf:plain-text id="os-name"> 

 Cisco Internet Operating System (tm) 

 </cdf:plain-text> 

 107 
SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 <cpe:cpe-list> 

 <cpe:cpe-item name="cpe://cisco:ios:12.3"> 

 <cpe:title>Cisco IOS version 12.3</cpe:title> 

 </cpe:cpe-item> 

 <cpe:cpe-item name="cpe://cisco:ios:12.2"> 

 <cpe:title>Cisco IOS version 12.2</cpe:title> 

 </cpe:cpe-item> 

 <cpe:cpe-item name="cpe://cisco:ios:12.1"> 

 <cpe:title>Cisco IOS version 12.1</cpe:title> 

 </cpe:cpe-item> 

 <cpe:cpe-item name="cpe://cisco:ios:12.0"> 

 <cpe:title>Cisco IOS version 12.0</cpe:title> 

 </cpe:cpe-item> 

 <cpe:cpe-item name="cpe://cisco:ios:11.3"> 

 <cpe:title>Cisco IOS version 11.3</cpe:title> 

 </cpe:cpe-item> 

 </cpe:cpe-list> 

 <cdf:platform idref="cpe://cisco:ios:12.3"/> 

 <cdf:platform idref="cpe://cisco:ios:12.2"/> 

 <cdf:platform idref="cpe://cisco:ios:12.1"/> 

 <cdf:platform idref="cpe://cisco:ios:12.0"/> 

 <cdf:platform idref="cpe://cisco:ios:11.3"/> 

 <cdf:version>0.1.15</cdf:version> 

 <cdf:model system="urn:xccdf:scoring:default"/> 

 <cdf:model system="urn:xccdf:scoring:flat"/> 

 <cdf:model system="urn:bindview.com:scoring:relative"> 

 <cdf:param name="floor">0.0</cdf:param> 

 <cdf:param name="ceiling">1000</cdf:param> 

 </cdf:model> 

 <cdf:Profile id="profile1" prohibitChanges="1" note-tag="lenient"> 

 <cdf:title>Sample Profile No. 1</cdf:title> 

 <cdf:select idref="mgmt-plane" selected="0"/> 

 <cdf:select idref="ctrl-plane" selected="1"/> 

 <cdf:select idref="finger" selected="1"/> 

 <cdf:set-value idref="exec-timeout-time">30</cdf:set-value> 

 <cdf:refine-value idref="buffered-logging-level" 

 selector="lenient"/> 

 </cdf:Profile> 

 <cdf:Profile id="profile2" extends="profile1" note-tag="strict"> 

 <cdf:title override="1">Sample Profile No. 2</cdf:title> 

 <cdf:select idref="mgmt-plane" selected="1"/> 

 <cdf:select idref="data-plane" selected="1"/> 

 <cdf:set-value idref="exec-timeout-time">10</cdf:set-value> 

 <cdf:refine-value idref="buffered-logging-level" selector="strict"/> 

 <cdf:refine-rule idref="no-tcp-small-servers" 

 weight="0.8" severity="medium"/> 

 </cdf:Profile> 

 <cdf:Value id="exec-timeout-time" type="number" 

 operator="less than or equal"> 

 <cdf:title>IOS - line exec timeout value</cdf:title> 

 <cdf:description> 

 The length of time, in minutes, that an interactive session 

 should be allowed to stay idle before being terminated. 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 </cdf:description> 

 <cdf:question>Session exec timeout time (in minutes)</cdf:question> 

 <cdf:value>10</cdf:value> 

 <cdf:default>15</cdf:default> 

 <cdf:lower-bound>1</cdf:lower-bound> 

 <cdf:upper-bound>60</cdf:upper-bound> 

 </cdf:Value> 

 <cdf:Group id="mgmt-plane" selected="1" prohibitChanges="1" weight="3"> 

 <cdf:title>Management Plane Rules</cdf:title> 

 <cdf:description> 

 Services, settings, and data streams related tosetting up 

 and examining the static configuration of the router, and the 

 authentication and authorization of administrators/operators. 

 </cdf:description> 

 <cdf:requires idref="no-directed-broadcast no-tcp-small-servers"/> 

 <cdf:Rule id="no-finger-service-base" selected="0" weight="5.0" 

 prohibitChanges="1" hidden="1" 

 abstract="1" cluster-id="finger"> 

 <cdf:title>IOS - no IP finger service</cdf:title> 

 <cdf:description> 

 Disable the finger service, it can reveal information 

 about logged in users to unauthorized parties. 

 (For <cdf:sub idref="os-name"/> version 11.3 and later.) 

 </cdf:description> 

 <cdf:question>Prohibit the finger service</cdf:question> 

 <cdf:fixtext fixref="no-finger" xml:lang="en"> 

 Turn off the finger service altogether, 

 it is <htm:i>very</htm:i> rarely used. 

 </cdf:fixtext> 

 <cdf:check system="http://oval.mitre.org/XMLSchema/oval"> 

 <cdf:check-content-ref href="iosDefns.xml" name="OVAL1002"/> 

 </cdf:check> 

 </cdf:Rule> 

 <cdf:Rule id="ios11-no-finger-service" 

 selected="0" prohibitChanges="1" 

 hidden="0" weight="5" extends="no-finger-service-base"> 

 <cdf:title override="1">IOS 11 - no IP finger service</cdf:title> 

 <cdf:platform idref="cpe://cisco:ios:11.3"/> 

 <cdf:fix id="no-finger" system="urn:xccdf:fix:system:commands" 

 disruption="low" strategy="disable"> 

 no service finger 

 </cdf:fix> 

 </cdf:Rule> 

 <cdf:Rule id="ios12-no-finger-service" 

 selected="0" prohibitChanges="1" 

 hidden="0" weight="5" extends="no-finger-service-base"> 

 <cdf:title override="1">IOS 12 - no IP finger service</cdf:title> 

 <cdf:platform idref="cpe://cisco:ios:12.3"/> 

 <cdf:platform idref="cpe://cisco:ios:12.2"/> 

 <cdf:platform idref="cpe://cisco:ios:12.1"/> 

 <cdf:platform idref="cpe://cisco:ios:12.0"/> 

 <cdf:fix id="no-finger" system="urn:xccdf:fix:system:commands" 

 disruption="low" strategy="disable"> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 no ip finger 

 </cdf:fix> 

 </cdf:Rule> 

 <cdf:Rule id="req-exec-timeout" selected="1" weight="8" multiple="1"> 

 <cdf:title>Require exec timeout on admin sessions</cdf:title> 

 <cdf:description> 

 Configure each administrative access line to terminate idle 

 sessions after a fixed period of time determined by local policy 

 </cdf:description> 

 <cdf:question>Require admin session idle timeout</cdf:question> 

 <cdf:profile-note tag="lenient"> 

 Half an hour 

 </cdf:profile-note> 

 <cdf:profile-note tag="strict"> 

 Ten minutes or less 

 </cdf:profile-note> 

 <cdf:fix strategy="configure" disruption="low" 

 system="urn:xccdf:fix:commands"> 

 line vty 0 4 

 exec-timeout <cdf:sub idref="exec-timeout-time"/> 

 </cdf:fix> 

 <cdf:check system="http://oval.mitre.org/XMLSchema/oval" id="foo"> 

 <cdf:check-export value-id="exec-timeout-time" 

 export-name="var-2"/> 

 <cdf:check-content-ref href="iosDefns.xml" name="OVAL708"/> 

 </cdf:check> 

 </cdf:Rule> 

 </cdf:Group> 

 <cdf:Group id="ctrl-plane" selected="1" prohibitChanges="1" weight="3"> 

 <cdf:title>Control Plane Rules</cdf:title> 

 <cdf:description> 

 Services, settings, and data streams that support the 

 operation and dynamic status of the router. 

 </cdf:description> 

 <cdf:question>Check rules related to system control</cdf:question> 

 <cdf:Value id="buffered-logging-level" type="string" 

 operator="equals" prohibitChanges="0" 

 interfaceHint="choice"> 

 <cdf:title>Logging level for buffered logging</cdf:title> 

 <cdf:description> 

 Logging level for buffered logging; this setting is 

 a severity level. Every audit message of this 

 severity or more (worse) will be logged. 

 </cdf:description> 

 <cdf:question>Select a buffered logging level</cdf:question> 

 <cdf:value selector="strict">informational</cdf:value> 

 <cdf:value selector="lenient">warning</cdf:value> 

 <cdf:value>notification</cdf:value> 

 <cdf:choices mustMatch="1"> 

 <cdf:choice>warning</cdf:choice> 

 <cdf:choice>notification</cdf:choice> 

 <cdf:choice>informational</cdf:choice> 

 </cdf:choices> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 <cdf:source uri="urn:OS:Cisco:IOS:logging:levels"/> 

 </cdf:Value> 

 <cdf:Rule id="no-tcp-small-servers" selected="1" 

 prohibitChanges="1" weight="7"> 

 <cdf:title>Disable tcp-small-servers</cdf:title> 

 <cdf:description> 

 Disable unnecessary services such as echo, chargen, etc. 

 </cdf:description> 

 <cdf:question>Prohibit TCP small services</cdf:question> 

 <cdf:fixtext> 

 Disable TCP small servers in IOS global config mode. 

 </cdf:fixtext> 

 <cdf:fix>no service tcp-small-servers</cdf:fix> 

 <cdf:check system="http://oval.mitre.org/XMLSchema/oval"> 

 <cdf:check-content-ref href="iosDefns.xml" name="OVAL1000"/> 

 </cdf:check> 

 </cdf:Rule> 

 <cdf:Rule id="no-udp-small-servers" selected="1" role="full" 

 prohibitChanges="1" weight="5.7"> 

 <cdf:title>Disable udp-small-servers</cdf:title> 

 <cdf:description> 

 Disable unnecessary UDP services such as echo, chargen, etc. 

 </cdf:description> 

 <cdf:question>Forbid UDP small services</cdf:question> 

 <cdf:fixtext> 

 Disable UDP small servers in IOS global config mode. 

 </cdf:fixtext> 

 <cdf:fix>no service udp-small-servers</cdf:fix> 

 <cdf:check system="http://oval.mitre.org/XMLSchema/oval"> 

 <cdf:check-content-ref href="iosDefns.xml" name="OVAL1001"/> 

 </cdf:check> 

 </cdf:Rule> 

 <cdf:Rule id="enabled-buffered-logging-at-level" selected="1" 

 prohibitChanges="0" weight="8.5"> 

 <cdf:title xml:lang="en"> 

 Ensure buffered logging enabled at proper level 

 </cdf:title> 

 <cdf:description> 

 Make sure that buffered logging is enabled, and that 

 the buffered logging level to one of the appropriate 

 levels, Warning or higher. 

 </cdf:description> 

 <cdf:question>Check buffered logging and level</cdf:question> 

 <cdf:fix> 

 logging on 

 logging buffered <cdf:sub idref="buffered-logging-level"/> 

 </cdf:fix> 

 <cdf:complex-check operator="AND" negate="1"> 

 <cdf:check system="http://oval.mitre.org/XMLSchema/oval"> 

 <cdf:check-export value-id="buffered-logging-level" 

 export-name="var-4"/> 

 <cdf:check-content-ref href="iosDefns.xml" 

 name="org.cisecurity.cisco.ios.logging.buf.level"/> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 </cdf:check> 

 <cdf:check system="http://oval.mitre.org/XMLSchema/oval"> 

 <cdf:check-content-ref href="iosDefns.xml" 

 name="org.cisecurity.cisco.ios.logging.enabled"/> 

 </cdf:check> 

 </cdf:complex-check> 

 </cdf:Rule> 

 </cdf:Group> 

 <cdf:Group id="data-plane" selected="1" prohibitChanges="1" weight="2"> 

 <cdf:title>Data Plane Level 1</cdf:title> 

 <cdf:description> 

 Services and settings related to the data passing through 

 the router (as opposed to directed to it). Basically, the 

 data plane is for everything not in control or mgmt planes. 

 </cdf:description> 

 <cdf:question>Check rules related to data flow</cdf:question> 

 

 <cdf:Group id="routing-rules" selected="1" prohibitChanges="1"> 

 <cdf:title>Routing Rules</cdf:title> 

 <cdf:description> 

 Rules in this group affect traffic forwarded through the 

 router, including router actions taken on receipt of 

 special data traffic. 

 </cdf:description> 

 <cdf:question>Apply standard forwarding protections</cdf:question> 

 <cdf:Rule id="no-directed-broadcast" weight="7" multiple="1" 

 selected="1" prohibitChanges="1"> 

 <cdf:title>IOS - no directed broadcasts</cdf:title> 

 <cdf:description> 

 Disable IP directed broadcast on each interface. 

 </cdf:description> 

 <cdf:question>Forbid IP directed broadcast</cdf:question> 

 <cdf:fixtext> 

 Disable IP directed broadcast on each interface 

 using IOS interface configuration mode. 

 </cdf:fixtext> 

 <cdf:fix> 

 interface <cdf:instance context="interface"/> 

 no ip directed-broadcast 

 </cdf:fix> 

 <cdf:check system="http://oval.mitre.org/XMLSchema/oval"> 

 <cdf:check-content-ref href="iosDefns.xml" name="OVAL1101"/> 

 </cdf:check> 

 </cdf:Rule> 

 </cdf:Group> 

 </cdf:Group> 

 <cdf:TestResult id="ios-test-5" 

 end-time="2004-09-25T13:45:02-04:00"> 

 <cdf:benchmark href="ios-sample-v1.1.xccdf.xml"/> 

 <cdf:title>Sample Results Block</cdf:title> 

 <cdf:remark>Test run by Bob on Sept 25</cdf:remark> 

 <cdf:target>lower.test.net</cdf:target> 

 <cdf:target-address>192.168.248.1</cdf:target-address> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

 <cdf:target-address>2001:8::1</cdf:target-address> 

 <cdf:target-facts> 

 <cdf:fact type="string" name="urn:xccdf:fact:ethernet:MAC"> 

 02:50:e6:c0:14:39 

 </cdf:fact> 

 <cdf:fact name="urn:xccdf:fact:OS:IOS">1</cdf:fact> 

 <cdf:fact name="urn:xccdf:fact:OS:IOS:12">1</cdf:fact> 

 <cdf:fact name="urn:xccdf:fact:OS:IOS:12:3">1</cdf:fact> 

 <cdf:fact name="urn:xccdf:fact:OS:IOS:12:3:14T">1</cdf:fact> 

 <cdf:fact type="string" name="urn:xccdf:fact:OS:IOS:relname"> 

 12.3(14)T 

 </cdf:fact> 

 </cdf:target-facts> 

 <cdf:set-value idref="exec-timeout-time">10</cdf:set-value> 

 <cdf:rule-result idref ="ios12-no-finger-service" 

 time="2004-09-25T13:45:00-04:00"> 

 <cdf:result>pass</cdf:result> 

 </cdf:rule-result> 

 <cdf:rule-result idref ="req-exec-timeout" 

 time="2004-09-25T13:45:06-04:00"> 

 <cdf:result>pass</cdf:result> 

 <cdf:override time="2004-09-25T13:59:00-04:00" 

 authority="Neal Ziring"> 

 <cdf:old-result>fail</cdf:old-result> 

 <cdf:new-result>pass</cdf:new-result> 

 <cdf:remark>Test override</cdf:remark> 

 </cdf:override> 

 <cdf:instance context="line">console</cdf:instance> 

 <cdf:fix> 

 line console 

 exec-timeout 10 0 

 </cdf:fix> 

 </cdf:rule-result> 

 <cdf:rule-result idref="ios12-no-finger-service"> 

 <cdf:result>notselected</cdf:result> 

 </cdf:rule-result> 

 <cdf:score system="urn:xccdf:model:default">67.5</cdf:score> 

 <cdf:score system="urn:xccdf:model:flat" maximum="214"> 

 157.5 

 </cdf:score> 

 </cdf:TestResult> 

</cdf:Benchmark> 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

8. Appendix C – Pre-Defined URIs 

The following URLs and URNs are defined for XCCDF 1.1. 

Long-Term Identification Systems 

These URIs may appear as the value of the system attribute of an ident element in a Rule. 

http://cve.mitre.org/ 

MITRE’s Common Vulnerabilities and Exposures – the identifier value should be a CVE 

number or CVE candidate number. 

http://www.cert.org/ 

CERT Coordination Center – the identifier value should be a CERT advisory identifier 

(e.g. “CA-2004-02”). 

http://www.us-cert.gov/cas/techalerts/ 

US-CERT technical cyber security alerts – the identifier value should be a technical 

cyber security alert ID (e.g. “TA05-189A”) 

http://www.kb.cert.org/ 

US-CERT vulnerability notes database – the identifier values should be a vulnerability 

note number (e.g. “709220”). 

http://iase.disa.mil/IAalerts/ 

DISA Information Assurance Vulnerability Alerts (IAVA) – the identifier value should 

be a DOD IAVA identifier. 

Check Systems 

These URIs may appear as the value of the system attribute of a check element (see p. 49). 

http://oval.mitre.org/XMLSchema/oval 

MITRE’s Open Vulnerability Assessment Language (see [15]). 

http://www.cisecurity.org/xccdf/interactive/1.0 

Center for Internet Security interactive query check system, used for asking the user 

questions about the target system during application of a security guidance document. 

Scoring Models 

These URIs may appear as the value of the system attribute on the model element or a score 

element (see pp. 60 and 68). 

urn:xccdf:scoring:default 

This specifies the default (XCCDF 1.0) scoring model. 

urn:xccdf:scoring:flat 

This specifies the flat, weighted scoring model. 

urn:xccdf:scoring:flat-unweighted 

This specifies the flat scoring model with weights ignored (all weights set to 1). 

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Remediation Systems 

The URIs represent remediation sources, mechanisms, schemes, or providers. They may appear 

as the system attribute on a fix element (see p. 55). 

urn:xccdf:fix:commands 

This specifies that the content of the fix element is a list of target system commands; 

executed in order, the commands should bring the target system into compliance with the 

Rule. 

urn:xccdf:fix:urls 

This specifies that the content of the fix element is a list of one or more URLs. The 

resources identified by the URLs should be applied to bring the system into compliance 

with the Rule. 

urn:xccdf:fix:script:language

A URN of this form specifies that the content of the fix element is a script written in the 

given language. Executing the script should bring the target system into compliance with 

the Rule. The following languages are pre-defined: 

• sh – Bourne shell 

• csh – C Shell 

• perl – Perl 

• batch – Windows batch script 

• python – Python and all Python-based scripting languages 

• vbscript – Visual Basic Script (VBS) 

• javascript – Javascript (ECMAScript, JScript) 

• tcl – Tcl and all Tcl-based scripting languages 

urn:xccdf:fix:patch:vendor

A URN of this form specifies that the content of the fix element is a patch identifier, in 

proprietary format as defined by the vendor. The vendor string should be the common 

short name of the vendor (e.g., “Sun”, “Microsoft”) or the vendor’s DNS name (e.g., 

“hp.com”, “apache.org”). 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

9. Appendix D – References 

[1] Fallside, David C., XML Schema Part 0: Primer, W3C Recommendation, May 

2001. (http://www.w3.org/) 

[2] Biron, Paul V. and Malhotra, Ashok, XML Schema Part 2: Datatypes, W3C 

Recommendation, May 2001. (http://www.w3.org/) 

[3] Buttner, Andrew, “<Oval SQL=’false’>”, presentation, The MITRE Corporation, 

October 2003. 

[4] Baker, Mark et al, XHTML Basic, W3C Recommendation, 

December 2000. (http://www.w3.org/) 

[5] Bray, Tim et al, Namespaces in XML, W3C Recommendation, 

January 1999. (http://www.w3.org/) 

[6] Jones, George, “Introduction to RAT”, presentation, Center for Internet Security, 

October 2003. 

[7] Calabrese, Chris, “VulnTrack”, presentation at 1st XCCDF Workshop, October 

2003. 

[8] Davis, Mark, “Unicode Regular Expressions”, Unicode Technical 

Recommendation No. 18, version 9, January 2004. 

[9] Bartel et al, “XML – Signature Syntax and Processing”, W3C Recommendation, 

February 2002. (http://www.w3.org/) 

[10] Marsh, J. and Orchard, D., “XML Inclusions (XInclude) Version 1.0”, 

W3C Candidate Recommendation, April 2004. (http://www.w3.org/) 

[11] Hillmann, Diane, “Using Dublin Core”, DCMI, August 2003. 

(http://dublincore.org/) 

[12] “Security Configuration Checklists Program for IT Products”, NIST Special 

Publication 800-70, August 2004. (http://checklists.nist.gov/) 

[13] Johnston, P. and Powell, A., “Guidelines for Implementing Dublin Core in 

XML”, DCMI, April 2003. (http://dublincore.org/) 

[14] Ziring, N. and Wack, J., “Specification for the Extensible Configuration Checklist 

Description Format (XCCDF)”, NIST IR 7188, January 2005. 

[15] “OVAL – The Open Vulnerability and Assessment Language”, The MITRE 

Corporation, September 2006. (http://oval.mitre.org/) 

[16] Buttner, A., Wittbold, T., and Ziring, N., “Common Platform Enumeration (CPE) 

– Name Format and Description”, MITRE Corporation, December 2006. 

(http://cpe.mitre.org/) 

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SPECIFICATION FOR THE EXTENSIBLE CONFIGURATION CHECKLIST DESCRIPTION FORMAT (XCCDF) VERSION 1.1.3 

Appendix E – Acronym List 

CIS Center for Internet Security 

COTS Commercial Off-the-Shelf 

CPE Common Platform Enumeration 

CVE Common Vulnerabilities and Exposures 

DISA Defense Information Systems Agency 

DNS Domain Name System 

DOD Department of Defense 

FIPS Federal Information Processing Standards 

FISMA Federal Information Security Management Act 

FSO Field Security Office 

GOTS Government Off-the-Shelf 

GUI Graphical User Interface 

HIPAA Health Insurance Portability and Accountability Act 

HTML Hypertext Markup Language 

IPv4 Internet Protocol version 4 

IPv6 Internet Protocol version 6 

IT Information Technology 

ITL Information Technology Laboratory 

MAC Media Access Control 

NIST National Institute of Standards and Technology 

NSA National Security Agency 

NVD National Vulnerability Database 

OMB Office of Management and Budget 

OS Operating System 

OVAL Open Vulnerability and Assessment Language 

SP Special Publication 

STIG Secure Technology Implementation Guide 

UML Unified Modeling Language 

URI Uniform Resource Identifier 

URL Uniform Resource Locator 

VMS Vulnerability Management System 

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W3C World Wide Web Consortium 

XCCDF Extensible Configuration Checklist Description Format 

XHTML Extensible Hypertext Markup Language 

XML Extensible Markup Language 

XSLT Extensible Stylesheet Language Transformation 

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