Data from Configuration Repository: Network Device Configuration Dump

Adversaries may access network configuration files to collect sensitive data about the device and the network. The network configuration is a file containing parameters that determine the operation of the device. The device typically stores an in-memory copy of the configuration while operating, and a separate configuration on non-volatile storage to load after device reset. Adversaries can inspect the configuration files to reveal information about the target network and its layout, the network device and its software, or identifying legitimate accounts and credentials for later use.

Adversaries can use common management tools and protocols, such as Simple Network Management Protocol (SNMP) and Smart Install (SMI), to access network configuration files.(Citation: US-CERT TA18-106A Network Infrastructure Devices 2018)(Citation: Cisco Blog Legacy Device Attacks) These tools may be used to query specific data from a configuration repository or configure the device to export the configuration for later analysis.

Identify network traffic sent or received by untrusted hosts or networks. Configure signatures to identify strings that may be found in a network device configuration.(Citation: US-CERT TA18-068A 2018)


Data from Configuration Repository: SNMP (MIB Dump)

Adversaries may target the Management Information Base (MIB) to collect and/or mine valuable information in a network managed using Simple Network Management Protocol (SNMP).

The MIB is a configuration repository that stores variable information accessible via SNMP in the form of object identifiers (OID). Each OID identifies a variable that can be read or set and permits active management tasks, such as configuration changes, through remote modification of these variables. SNMP can give administrators great insight in their systems, such as, system information, description of hardware, physical location, and software packages(Citation: SANS Information Security Reading Room Securing SNMP Securing SNMP). The MIB may also contain device operational information, including running configuration, routing table, and interface details.

Adversaries may use SNMP queries to collect MIB content directly from SNMP-managed devices in order to collect network information that allows the adversary to build network maps and facilitate future targeted exploitation.(Citation: US-CERT-TA18-106A)(Citation: Cisco Blog Legacy Device Attacks)

Identify network traffic sent or received by untrusted hosts or networks that expose MIB content or use unauthorized protocols.(Citation: Cisco Advisory SNMP v3 Authentication Vulnerabilities)


Data from Information Repositories

Adversaries may leverage information repositories to mine valuable information. Information repositories are tools that allow for storage of information, typically to facilitate collaboration or information sharing between users, and can store a wide variety of data that may aid adversaries in further objectives, or direct access to the target information. Adversaries may also abuse external sharing features to share sensitive documents with recipients outside of the organization.

The following is a brief list of example information that may hold potential value to an adversary and may also be found on an information repository:

* Policies, procedures, and standards
* Physical / logical network diagrams
* System architecture diagrams
* Technical system documentation
* Testing / development credentials
* Work / project schedules
* Source code snippets
* Links to network shares and other internal resources

Information stored in a repository may vary based on the specific instance or environment. Specific common information repositories include web-based platforms such as [Sharepoint](https://attack.mitre.org/techniques/T1213/002) and [Confluence](https://attack.mitre.org/techniques/T1213/001), specific services such as Code Repositories, IaaS databases, enterprise databases, and other storage infrastructure such as SQL Server.

As information repositories generally have a considerably large user base, detection of malicious use can be non-trivial. At minimum, access to information repositories performed by privileged users (for example, Active Directory Domain, Enterprise, or Schema Administrators) should be closely monitored and alerted upon, as these types of accounts should generally not be used to access information repositories. If the capability exists, it may be of value to monitor and alert on users that are retrieving and viewing a large number of documents and pages; this behavior may be indicative of programmatic means being used to retrieve all data within the repository. In environments with high-maturity, it may be possible to leverage User-Behavioral Analytics (UBA) platforms to detect and alert on user based anomalies.

The user access logging within Microsoft's SharePoint can be configured to report access to certain pages and documents. (Citation: Microsoft SharePoint Logging) Sharepoint audit logging can also be configured to report when a user shares a resource. (Citation: Sharepoint Sharing Events) The user access logging within Atlassian's Confluence can also be configured to report access to certain pages and documents through AccessLogFilter. (Citation: Atlassian Confluence Logging) Additional log storage and analysis infrastructure will likely be required for more robust detection capabilities.


Data from Information Repositories: Code Repositories

Adversaries may leverage code repositories to collect valuable information. Code repositories are tools/services that store source code and automate software builds. They may be hosted internally or privately on third party sites such as Github, GitLab, SourceForge, and BitBucket. Users typically interact with code repositories through a web application or command-line utilities such as git.

Once adversaries gain access to a victim network or a private code repository, they may collect sensitive information such as proprietary source code or credentials contained within software's source code.  Having access to software's source code may allow adversaries to develop [Exploits](https://attack.mitre.org/techniques/T1587/004), while credentials may provide access to additional resources using [Valid Accounts](https://attack.mitre.org/techniques/T1078).(Citation: Wired Uber Breach)(Citation: Krebs Adobe)

**Note:** This is distinct from [Code Repositories](https://attack.mitre.org/techniques/T1593/003), which focuses on conducting [Reconnaissance](https://attack.mitre.org/tactics/TA0043) via public code repositories.

Monitor access to code repositories, especially performed by privileged users such as Active Directory Domain or Enterprise Administrators as these types of accounts should generally not be used to access code repositories. In environments with high-maturity, it may be possible to leverage User-Behavioral Analytics (UBA) platforms to detect and alert on user-based anomalies.


Data from Information Repositories: Confluence

Adversaries may leverage Confluence repositories to mine valuable information. Often found in development environments alongside Atlassian JIRA, Confluence is generally used to store development-related documentation, however, in general may contain more diverse categories of useful information, such as:

* Policies, procedures, and standards
* Physical / logical network diagrams
* System architecture diagrams
* Technical system documentation
* Testing / development credentials
* Work / project schedules
* Source code snippets
* Links to network shares and other internal resources

Monitor access to Confluence repositories performed by privileged users (for example, Active Directory Domain, Enterprise, or Schema Administrators) as these types of accounts should generally not be used to access information repositories. If the capability exists, it may be of value to monitor and alert on users that are retrieving and viewing a large number of documents and pages; this behavior may be indicative of programmatic means being used to retrieve all data within the repository. In environments with high-maturity, it may be possible to leverage User-Behavioral Analytics (UBA) platforms to detect and alert on user based anomalies.

User access logging within Atlassian's Confluence can be configured to report access to certain pages and documents through AccessLogFilter. (Citation: Atlassian Confluence Logging) Additional log storage and analysis infrastructure will likely be required for more robust detection capabilities.


Data from Information Repositories: Sharepoint

Adversaries may leverage the SharePoint repository as a source to mine valuable information. SharePoint will often contain useful information for an adversary to learn about the structure and functionality of the internal network and systems. For example, the following is a list of example information that may hold potential value to an adversary and may also be found on SharePoint:

* Policies, procedures, and standards
* Physical / logical network diagrams
* System architecture diagrams
* Technical system documentation
* Testing / development credentials
* Work / project schedules
* Source code snippets
* Links to network shares and other internal resources

The user access logging within Microsoft's SharePoint can be configured to report access to certain pages and documents. (Citation: Microsoft SharePoint Logging). As information repositories generally have a considerably large user base, detection of malicious use can be non-trivial. At minimum, access to information repositories performed by privileged users (for example, Active Directory Domain, Enterprise, or Schema Administrators) should be closely monitored and alerted upon, as these types of accounts should generally not be used to access information repositories. If the capability exists, it may be of value to monitor and alert on users that are retrieving and viewing a large number of documents and pages; this behavior may be indicative of programmatic means being used to retrieve all data within the repository. In environments with high-maturity, it may be possible to leverage User-Behavioral Analytics (UBA) platforms to detect and alert on user based anomalies.


Data from Local System

Adversaries may search local system sources, such as file systems and configuration files or local databases, to find files of interest and sensitive data prior to Exfiltration.

Adversaries may do this using a [Command and Scripting Interpreter](https://attack.mitre.org/techniques/T1059), such as [cmd](https://attack.mitre.org/software/S0106) as well as a [Network Device CLI](https://attack.mitre.org/techniques/T1059/008), which have functionality to interact with the file system to gather information.(Citation: show_run_config_cmd_cisco) Adversaries may also use [Automated Collection](https://attack.mitre.org/techniques/T1119) on the local system.

Monitor processes and command-line arguments for actions that could be taken to collect files from a system. Remote access tools with built-in features may interact directly with the Windows API to gather data. Further, [Network Device CLI](https://attack.mitre.org/techniques/T1059/008) commands may also be used to collect files such as configuration files with built-in features native to the network device platform.(Citation: Mandiant APT41 Global Intrusion )(Citation: US-CERT-TA18-106A) Monitor CLI activity for unexpected or unauthorized use commands being run by non-standard users from non-standard locations. Data may also be acquired through Windows system management tools such as [Windows Management Instrumentation](https://attack.mitre.org/techniques/T1047) and [PowerShell](https://attack.mitre.org/techniques/T1059/001).

For network infrastructure devices, collect AAA logging to monitor `show` commands that view configuration files.


Data from Network Shared Drive

Adversaries may search network shares on computers they have compromised to find files of interest. Sensitive data can be collected from remote systems via shared network drives (host shared directory, network file server, etc.) that are accessible from the current system prior to Exfiltration. Interactive command shells may be in use, and common functionality within [cmd](https://attack.mitre.org/software/S0106) may be used to gather information.

Monitor processes and command-line arguments for actions that could be taken to collect files from a network share. Remote access tools with built-in features may interact directly with the Windows API to gather data. Data may also be acquired through Windows system management tools such as [Windows Management Instrumentation](https://attack.mitre.org/techniques/T1047) and [PowerShell](https://attack.mitre.org/techniques/T1059/001).


Data from Removable Media

Adversaries may search connected removable media on computers they have compromised to find files of interest. Sensitive data can be collected from any removable media (optical disk drive, USB memory, etc.) connected to the compromised system prior to Exfiltration. Interactive command shells may be in use, and common functionality within [cmd](https://attack.mitre.org/software/S0106) may be used to gather information.

Some adversaries may also use [Automated Collection](https://attack.mitre.org/techniques/T1119) on removable media.

Monitor processes and command-line arguments for actions that could be taken to collect files from a system's connected removable media. Remote access tools with built-in features may interact directly with the Windows API to gather data. Data may also be acquired through Windows system management tools such as [Windows Management Instrumentation](https://attack.mitre.org/techniques/T1047) and [PowerShell](https://attack.mitre.org/techniques/T1059/001).


Debugger Evasion

Adversaries may employ various means to detect and avoid debuggers. Debuggers are typically used by defenders to trace and/or analyze the execution of potential malware payloads.(Citation: ProcessHacker Github)

Debugger evasion may include changing behaviors based on the results of the checks for the presence of artifacts indicative of a debugged environment. Similar to [Virtualization/Sandbox Evasion](https://attack.mitre.org/techniques/T1497), if the adversary detects a debugger, they may alter their malware to disengage from the victim or conceal the core functions of the implant. They may also search for debugger artifacts before dropping secondary or additional payloads.

Specific checks will vary based on the target and/or adversary, but may involve [Native API](https://attack.mitre.org/techniques/T1106) function calls such as IsDebuggerPresent() and  NtQueryInformationProcess(), or manually checking the BeingDebugged flag of the Process Environment Block (PEB). Other checks for debugging artifacts may also seek to enumerate hardware breakpoints, interrupt assembly opcodes, time checks, or measurements if exceptions are raised in the current process (assuming a present debugger would “swallow” or handle the potential error).(Citation: hasherezade debug)(Citation: AlKhaser Debug)(Citation: vxunderground debug)

Adversaries may use the information learned from these debugger checks during automated discovery to shape follow-on behaviors. Debuggers can also be evaded by detaching the process or flooding debug logs with meaningless data via messages produced by looping [Native API](https://attack.mitre.org/techniques/T1106) function calls such as OutputDebugStringW().(Citation: wardle evilquest partii)(Citation: Checkpoint Dridex Jan 2021)

Debugger related system checks will likely occur in the first steps of an operation but may also occur throughout as an adversary learns the environment. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as lateral movement, based on the information obtained. Detecting actions related to debugger identification may be difficult depending on the adversary's implementation and monitoring required. Monitoring for suspicious [Native API](https://attack.mitre.org/techniques/T1106) function calls as well as processes being spawned that gather a variety of system information or perform other forms of Discovery, especially in a short period of time, may aid in detection.

Monitor debugger logs for signs of abnormal and potentially malicious activity.


Defacement

Adversaries may modify visual content available internally or externally to an enterprise network, thus affecting the integrity of the original content. Reasons for [Defacement](https://attack.mitre.org/techniques/T1491) include delivering messaging, intimidation, or claiming (possibly false) credit for an intrusion. Disturbing or offensive images may be used as a part of [Defacement](https://attack.mitre.org/techniques/T1491) in order to cause user discomfort, or to pressure compliance with accompanying messages.

Monitor internal and external websites for unplanned content changes. Monitor application logs for abnormal behavior that may indicate attempted or successful exploitation. Use deep packet inspection to look for artifacts of common exploit traffic, such as SQL injection. Web Application Firewalls may detect improper inputs attempting exploitation.


Defacement: External Defacement

An adversary may deface systems external to an organization in an attempt to deliver messaging, intimidate, or otherwise mislead an organization or users. [External Defacement](https://attack.mitre.org/techniques/T1491/002) may ultimately cause users to distrust the systems and to question/discredit the system’s integrity. Externally-facing websites are a common victim of defacement; often targeted by adversary and hacktivist groups in order to push a political message or spread propaganda.(Citation: FireEye Cyber Threats to Media Industries)(Citation: Kevin Mandia Statement to US Senate Committee on Intelligence)(Citation: Anonymous Hackers Deface Russian Govt Site) [External Defacement](https://attack.mitre.org/techniques/T1491/002) may be used as a catalyst to trigger events, or as a response to actions taken by an organization or government. Similarly, website defacement may also be used as setup, or a precursor, for future attacks such as [Drive-by Compromise](https://attack.mitre.org/techniques/T1189).(Citation: Trend Micro Deep Dive Into Defacement)

Monitor external websites for unplanned content changes. Monitor application logs for abnormal behavior that may indicate attempted or successful exploitation. Use deep packet inspection to look for artifacts of common exploit traffic, such as SQL injection. Web Application Firewalls may detect improper inputs attempting exploitation.


Defacement: Internal Defacement

An adversary may deface systems internal to an organization in an attempt to intimidate or mislead users, thus discrediting the integrity of the systems. This may take the form of modifications to internal websites, or directly to user systems with the replacement of the desktop wallpaper.(Citation: Novetta Blockbuster) Disturbing or offensive images may be used as a part of [Internal Defacement](https://attack.mitre.org/techniques/T1491/001) in order to cause user discomfort, or to pressure compliance with accompanying messages. Since internally defacing systems exposes an adversary's presence, it often takes place after other intrusion goals have been accomplished.(Citation: Novetta Blockbuster Destructive Malware)

Monitor internal and websites for unplanned content changes. Monitor application logs for abnormal behavior that may indicate attempted or successful exploitation. Use deep packet inspection to look for artifacts of common exploit traffic, such as SQL injection. Web Application Firewalls may detect improper inputs attempting exploitation.


Deobfuscate/Decode Files or Information

Adversaries may use [Obfuscated Files or Information](https://attack.mitre.org/techniques/T1027) to hide artifacts of an intrusion from analysis. They may require separate mechanisms to decode or deobfuscate that information depending on how they intend to use it. Methods for doing that include built-in functionality of malware or by using utilities present on the system.

One such example is the use of [certutil](https://attack.mitre.org/software/S0160) to decode a remote access tool portable executable file that has been hidden inside a certificate file.(Citation: Malwarebytes Targeted Attack against Saudi Arabia) Another example is using the Windows copy /b command to reassemble binary fragments into a malicious payload.(Citation: Carbon Black Obfuscation Sept 2016)

Sometimes a user's action may be required to open it for deobfuscation or decryption as part of [User Execution](https://attack.mitre.org/techniques/T1204). The user may also be required to input a password to open a password protected compressed/encrypted file that was provided by the adversary. (Citation: Volexity PowerDuke November 2016)

Detecting the action of deobfuscating or decoding files or information may be difficult depending on the implementation. If the functionality is contained within malware and uses the Windows API, then attempting to detect malicious behavior before or after the action may yield better results than attempting to perform analysis on loaded libraries or API calls. If scripts are used, then collecting the scripts for analysis may be necessary. Perform process and command-line monitoring to detect potentially malicious behavior related to scripts and system utilities such as [certutil](https://attack.mitre.org/software/S0160).

Monitor the execution file paths and command-line arguments for common archive file applications and extensions, such as those for Zip and RAR archive tools, and correlate with other suspicious behavior to reduce false positives from normal user and administrator behavior.


Deploy Container

Adversaries may deploy a container into an environment to facilitate execution or evade defenses. In some cases, adversaries may deploy a new container to execute processes associated with a particular image or deployment, such as processes that execute or download malware. In others, an adversary may deploy a new container configured without network rules, user limitations, etc. to bypass existing defenses within the environment. In Kubernetes environments, an adversary may attempt to deploy a privileged or vulnerable container into a specific node in order to [Escape to Host](https://attack.mitre.org/techniques/T1611) and access other containers running on the node. (Citation: AppSecco Kubernetes Namespace Breakout 2020)

Containers can be deployed by various means, such as via Docker's create and start APIs or via a web application such as the Kubernetes dashboard or Kubeflow. (Citation: Docker Containers API)(Citation: Kubernetes Dashboard)(Citation: Kubeflow Pipelines) In Kubernetes environments, containers may be deployed through workloads such as ReplicaSets or DaemonSets, which can allow containers to be deployed across multiple nodes.(Citation: Kubernetes Workload Management) Adversaries may deploy containers based on retrieved or built malicious images or from benign images that download and execute malicious payloads at runtime.(Citation: Aqua Build Images on Hosts)

Monitor for suspicious or unknown container images and pods in your environment. Deploy logging agents on Kubernetes nodes and retrieve logs from sidecar proxies for application pods to detect malicious activity at the cluster level. In Docker, the daemon log provides insight into remote API calls, including those that deploy containers. Logs for management services or applications used to deploy containers other than the native technologies themselves should also be monitored.


Develop Capabilities

Adversaries may build capabilities that can be used during targeting. Rather than purchasing, freely downloading, or stealing capabilities, adversaries may develop their own capabilities in-house. This is the process of identifying development requirements and building solutions such as malware, exploits, and self-signed certificates. Adversaries may develop capabilities to support their operations throughout numerous phases of the adversary lifecycle.(Citation: Mandiant APT1)(Citation: Kaspersky Sofacy)(Citation: Bitdefender StrongPity June 2020)(Citation: Talos Promethium June 2020)

As with legitimate development efforts, different skill sets may be required for developing capabilities. The skills needed may be located in-house, or may need to be contracted out. Use of a contractor may be considered an extension of that adversary's development capabilities, provided the adversary plays a role in shaping requirements and maintains a degree of exclusivity to the capability.

Consider analyzing malware for features that may be associated with the adversary and/or their developers, such as compiler used, debugging artifacts, or code similarities. Malware repositories can also be used to identify additional samples associated with the adversary and identify development patterns over time.

Consider use of services that may aid in the tracking of certificates in use on sites across the Internet. In some cases it may be possible to pivot on known pieces of certificate information to uncover other adversary infrastructure.(Citation: Splunk Kovar Certificates 2017)

Much of this activity will take place outside the visibility of the target organization, making detection of this behavior difficult. Detection efforts may be focused on related stages of the adversary lifecycle, such as during Defense Evasion or Command and Control.


Develop Capabilities: Code Signing Certificates

Adversaries may create self-signed code signing certificates that can be used during targeting. Code signing is the process of digitally signing executables and scripts to confirm the software author and guarantee that the code has not been altered or corrupted. Code signing provides a level of authenticity for a program from the developer and a guarantee that the program has not been tampered with.(Citation: Wikipedia Code Signing) Users and/or security tools may trust a signed piece of code more than an unsigned piece of code even if they don't know who issued the certificate or who the author is.

Prior to [Code Signing](https://attack.mitre.org/techniques/T1553/002), adversaries may develop self-signed code signing certificates for use in operations.

Consider analyzing self-signed code signing certificates for features that may be associated with the adversary and/or their developers, such as the thumbprint, algorithm used, validity period, and common name. Malware repositories can also be used to identify additional samples associated with the adversary and identify patterns an adversary has used in crafting self-signed code signing certificates.

Much of this activity will take place outside the visibility of the target organization, making detection of this behavior difficult. Detection efforts may be focused on related follow-on behavior, such as [Code Signing](https://attack.mitre.org/techniques/T1553/002) or [Install Root Certificate](https://attack.mitre.org/techniques/T1553/004).


Develop Capabilities: Digital Certificates

Adversaries may create self-signed SSL/TLS certificates that can be used during targeting. SSL/TLS certificates are designed to instill trust. They include information about the key, information about its owner's identity, and the digital signature of an entity that has verified the certificate's contents are correct. If the signature is valid, and the person examining the certificate trusts the signer, then they know they can use that key to communicate with its owner. In the case of self-signing, digital certificates will lack the element of trust associated with the signature of a third-party certificate authority (CA).

Adversaries may create self-signed SSL/TLS certificates that can be used to further their operations, such as encrypting C2 traffic (ex: [Asymmetric Cryptography](https://attack.mitre.org/techniques/T1573/002) with [Web Protocols](https://attack.mitre.org/techniques/T1071/001)) or even enabling [Adversary-in-the-Middle](https://attack.mitre.org/techniques/T1557) if added to the root of trust (i.e. [Install Root Certificate](https://attack.mitre.org/techniques/T1553/004)).

After creating a digital certificate, an adversary may then install that certificate (see [Install Digital Certificate](https://attack.mitre.org/techniques/T1608/003)) on infrastructure under their control.

Consider use of services that may aid in the tracking of certificates in use on sites across the Internet. In some cases it may be possible to pivot on known pieces of certificate information to uncover other adversary infrastructure.(Citation: Splunk Kovar Certificates 2017)

Detection efforts may be focused on related behaviors, such as [Web Protocols](https://attack.mitre.org/techniques/T1071/001), [Asymmetric Cryptography](https://attack.mitre.org/techniques/T1573/002), and/or [Install Root Certificate](https://attack.mitre.org/techniques/T1553/004).


Develop Capabilities: Exploits

Adversaries may develop exploits that can be used during targeting. An exploit takes advantage of a bug or vulnerability in order to cause unintended or unanticipated behavior to occur on computer hardware or software. Rather than finding/modifying exploits from online or purchasing them from exploit vendors, an adversary may develop their own exploits.(Citation: NYTStuxnet) Adversaries may use information acquired via [Vulnerabilities](https://attack.mitre.org/techniques/T1588/006) to focus exploit development efforts. As part of the exploit development process, adversaries may uncover exploitable vulnerabilities through methods such as fuzzing and patch analysis.(Citation: Irongeek Sims BSides 2017)

As with legitimate development efforts, different skill sets may be required for developing exploits. The skills needed may be located in-house, or may need to be contracted out. Use of a contractor may be considered an extension of that adversary's exploit development capabilities, provided the adversary plays a role in shaping requirements and maintains an initial degree of exclusivity to the exploit.

Adversaries may use exploits during various phases of the adversary lifecycle (i.e. [Exploit Public-Facing Application](https://attack.mitre.org/techniques/T1190), [Exploitation for Client Execution](https://attack.mitre.org/techniques/T1203), [Exploitation for Privilege Escalation](https://attack.mitre.org/techniques/T1068), [Exploitation for Defense Evasion](https://attack.mitre.org/techniques/T1211), [Exploitation for Credential Access](https://attack.mitre.org/techniques/T1212), [Exploitation of Remote Services](https://attack.mitre.org/techniques/T1210), and [Application or System Exploitation](https://attack.mitre.org/techniques/T1499/004)).

Much of this activity will take place outside the visibility of the target organization, making detection of this behavior difficult. Detection efforts may be focused on behaviors relating to the use of exploits (i.e. [Exploit Public-Facing Application](https://attack.mitre.org/techniques/T1190), [Exploitation for Client Execution](https://attack.mitre.org/techniques/T1203), [Exploitation for Privilege Escalation](https://attack.mitre.org/techniques/T1068), [Exploitation for Defense Evasion](https://attack.mitre.org/techniques/T1211), [Exploitation for Credential Access](https://attack.mitre.org/techniques/T1212), [Exploitation of Remote Services](https://attack.mitre.org/techniques/T1210), and [Application or System Exploitation](https://attack.mitre.org/techniques/T1499/004)).


Develop Capabilities: Malware

Adversaries may develop malware and malware components that can be used during targeting. Building malicious software can include the development of payloads, droppers, post-compromise tools, backdoors (including backdoored images), packers, C2 protocols, and the creation of infected removable media. Adversaries may develop malware to support their operations, creating a means for maintaining control of remote machines, evading defenses, and executing post-compromise behaviors.(Citation: Mandiant APT1)(Citation: Kaspersky Sofacy)(Citation: ActiveMalwareEnergy)(Citation: FBI Flash FIN7 USB)

As with legitimate development efforts, different skill sets may be required for developing malware. The skills needed may be located in-house, or may need to be contracted out. Use of a contractor may be considered an extension of that adversary's malware development capabilities, provided the adversary plays a role in shaping requirements and maintains a degree of exclusivity to the malware.

Some aspects of malware development, such as C2 protocol development, may require adversaries to obtain additional infrastructure. For example, malware developed that will communicate with Twitter for C2, may require use of [Web Services](https://attack.mitre.org/techniques/T1583/006).(Citation: FireEye APT29)

Consider analyzing malware for features that may be associated with the adversary and/or their developers, such as compiler used, debugging artifacts, or code similarities. Malware repositories can also be used to identify additional samples associated with the adversary and identify development patterns over time.

Much of this activity will take place outside the visibility of the target organization, making detection of this behavior difficult. Detection efforts may be focused on post-compromise phases of the adversary lifecycle.


Device Driver Discovery

Adversaries may attempt to enumerate local device drivers on a victim host. Information about device drivers may highlight various insights that shape follow-on behaviors, such as the function/purpose of the host, present security tools (i.e. [Security Software Discovery](https://attack.mitre.org/techniques/T1518/001)) or other defenses (e.g., [Virtualization/Sandbox Evasion](https://attack.mitre.org/techniques/T1497)), as well as potential exploitable vulnerabilities (e.g., [Exploitation for Privilege Escalation](https://attack.mitre.org/techniques/T1068)).

Many OS utilities may provide information about local device drivers, such as `driverquery.exe` and the `EnumDeviceDrivers()` API function on Windows.(Citation: Microsoft Driverquery)(Citation: Microsoft EnumDeviceDrivers) Information about device drivers (as well as associated services, i.e., [System Service Discovery](https://attack.mitre.org/techniques/T1007)) may also be available in the Registry.(Citation: Microsoft Registry Drivers)

On Linux/macOS, device drivers (in the form of kernel modules) may be visible within `/dev` or using utilities such as `lsmod` and `modinfo`.(Citation: Linux Kernel Programming)(Citation: lsmod man)(Citation: modinfo man)


Direct Volume Access

Adversaries may directly access a volume to bypass file access controls and file system monitoring. Windows allows programs to have direct access to logical volumes. Programs with direct access may read and write files directly from the drive by analyzing file system data structures. This technique may bypass Windows file access controls as well as file system monitoring tools. (Citation: Hakobyan 2009)

Utilities, such as `NinjaCopy`, exist to perform these actions in PowerShell.(Citation: Github PowerSploit Ninjacopy) Adversaries may also use built-in or third-party utilities (such as `vssadmin`, `wbadmin`, and [esentutl](https://attack.mitre.org/software/S0404)) to create shadow copies or backups of data from system volumes.(Citation: LOLBAS Esentutl)

Monitor handle opens on drive volumes that are made by processes to determine when they may directly access logical drives. (Citation: Github PowerSploit Ninjacopy)

Monitor processes and command-line arguments for actions that could be taken to copy files from the logical drive and evade common file system protections. Since this technique may also be used through [PowerShell](https://attack.mitre.org/techniques/T1059/001), additional logging of PowerShell scripts is recommended.


Disk Wipe

Adversaries may wipe or corrupt raw disk data on specific systems or in large numbers in a network to interrupt availability to system and network resources. With direct write access to a disk, adversaries may attempt to overwrite portions of disk data. Adversaries may opt to wipe arbitrary portions of disk data and/or wipe disk structures like the master boot record (MBR). A complete wipe of all disk sectors may be attempted.

To maximize impact on the target organization in operations where network-wide availability interruption is the goal, malware used for wiping disks may have worm-like features to propagate across a network by leveraging additional techniques like [Valid Accounts](https://attack.mitre.org/techniques/T1078), [OS Credential Dumping](https://attack.mitre.org/techniques/T1003), and [SMB/Windows Admin Shares](https://attack.mitre.org/techniques/T1021/002).(Citation: Novetta Blockbuster Destructive Malware)

On network devices, adversaries may wipe configuration files and other data from the device using [Network Device CLI](https://attack.mitre.org/techniques/T1059/008) commands such as `erase`.(Citation: erase_cmd_cisco)

Look for attempts to read/write to sensitive locations like the partition boot sector, master boot record, disk partition table, or BIOS parameter block/superblock. Monitor for direct access read/write attempts using the <code>\\\\.\\</code> notation.(Citation: Microsoft Sysmon v6 May 2017) Monitor for unusual kernel driver installation activity.


Disk Wipe: Disk Content Wipe

Adversaries may erase the contents of storage devices on specific systems or in large numbers in a network to interrupt availability to system and network resources.

Adversaries may partially or completely overwrite the contents of a storage device rendering the data irrecoverable through the storage interface.(Citation: Novetta Blockbuster)(Citation: Novetta Blockbuster Destructive Malware)(Citation: DOJ Lazarus Sony 2018) Instead of wiping specific disk structures or files, adversaries with destructive intent may wipe arbitrary portions of disk content. To wipe disk content, adversaries may acquire direct access to the hard drive in order to overwrite arbitrarily sized portions of disk with random data.(Citation: Novetta Blockbuster Destructive Malware) Adversaries have also been observed leveraging third-party drivers like [RawDisk](https://attack.mitre.org/software/S0364) to directly access disk content.(Citation: Novetta Blockbuster)(Citation: Novetta Blockbuster Destructive Malware) This behavior is distinct from [Data Destruction](https://attack.mitre.org/techniques/T1485) because sections of the disk are erased instead of individual files.

To maximize impact on the target organization in operations where network-wide availability interruption is the goal, malware used for wiping disk content may have worm-like features to propagate across a network by leveraging additional techniques like [Valid Accounts](https://attack.mitre.org/techniques/T1078), [OS Credential Dumping](https://attack.mitre.org/techniques/T1003), and [SMB/Windows Admin Shares](https://attack.mitre.org/techniques/T1021/002).(Citation: Novetta Blockbuster Destructive Malware)

Look for attempts to read/write to sensitive locations like the partition boot sector or BIOS parameter block/superblock. Monitor for direct access read/write attempts using the <code>\\\\.\\</code> notation.(Citation: Microsoft Sysmon v6 May 2017) Monitor for unusual kernel driver installation activity.

For network infrastructure devices, collect AAA logging to monitor for `erase` commands that delete critical configuration files.


Disk Wipe: Disk Structure Wipe

Adversaries may corrupt or wipe the disk data structures on a hard drive necessary to boot a system; targeting specific critical systems or in large numbers in a network to interrupt availability to system and network resources.

Adversaries may attempt to render the system unable to boot by overwriting critical data located in structures such as the master boot record (MBR) or partition table.(Citation: Symantec Shamoon 2012)(Citation: FireEye Shamoon Nov 2016)(Citation: Palo Alto Shamoon Nov 2016)(Citation: Kaspersky StoneDrill 2017)(Citation: Unit 42 Shamoon3 2018) The data contained in disk structures may include the initial executable code for loading an operating system or the location of the file system partitions on disk. If this information is not present, the computer will not be able to load an operating system during the boot process, leaving the computer unavailable. [Disk Structure Wipe](https://attack.mitre.org/techniques/T1561/002) may be performed in isolation, or along with [Disk Content Wipe](https://attack.mitre.org/techniques/T1561/001) if all sectors of a disk are wiped.

On a network devices, adversaries may reformat the file system using [Network Device CLI](https://attack.mitre.org/techniques/T1059/008) commands such as `format`.(Citation: format_cmd_cisco)

To maximize impact on the target organization, malware designed for destroying disk structures may have worm-like features to propagate across a network by leveraging other techniques like [Valid Accounts](https://attack.mitre.org/techniques/T1078), [OS Credential Dumping](https://attack.mitre.org/techniques/T1003), and [SMB/Windows Admin Shares](https://attack.mitre.org/techniques/T1021/002).(Citation: Symantec Shamoon 2012)(Citation: FireEye Shamoon Nov 2016)(Citation: Palo Alto Shamoon Nov 2016)(Citation: Kaspersky StoneDrill 2017)

Look for attempts to read/write to sensitive locations like the master boot record and the disk partition table. Monitor for direct access read/write attempts using the <code>\\\\.\\</code> notation.(Citation: Microsoft Sysmon v6 May 2017) Monitor for unusual kernel driver installation activity.

For network infrastructure devices, collect AAA logging to monitor for `format` commands being run to erase the file structure and prevent recovery of the device.


Domain Trust Discovery

Adversaries may attempt to gather information on domain trust relationships that may be used to identify lateral movement opportunities in Windows multi-domain/forest environments. Domain trusts provide a mechanism for a domain to allow access to resources based on the authentication procedures of another domain.(Citation: Microsoft Trusts) Domain trusts allow the users of the trusted domain to access resources in the trusting domain. The information discovered may help the adversary conduct [SID-History Injection](https://attack.mitre.org/techniques/T1134/005), [Pass the Ticket](https://attack.mitre.org/techniques/T1550/003), and [Kerberoasting](https://attack.mitre.org/techniques/T1558/003).(Citation: AdSecurity Forging Trust Tickets)(Citation: Harmj0y Domain Trusts) Domain trusts can be enumerated using the `DSEnumerateDomainTrusts()` Win32 API call, .NET methods, and LDAP.(Citation: Harmj0y Domain Trusts) The Windows utility [Nltest](https://attack.mitre.org/software/S0359) is known to be used by adversaries to enumerate domain trusts.(Citation: Microsoft Operation Wilysupply)

System and network discovery techniques normally occur throughout an operation as an adversary learns the environment. Data and events should not be viewed in isolation but as part of a chain of behavior that could lead to other activities based on the information obtained.

Monitor processes and command-line arguments for actions that could be taken to gather system and network information, such as `nltest /domain_trusts`. Remote access tools with built-in features may interact directly with the Windows API to gather information. Look for the `DSEnumerateDomainTrusts()` Win32 API call to spot activity associated with [Domain Trust Discovery](https://attack.mitre.org/techniques/T1482).(Citation: Harmj0y Domain Trusts) Information may also be acquired through Windows system management tools such as [PowerShell](https://attack.mitre.org/techniques/T1059/001). The .NET method `GetAllTrustRelationships()` can be an indicator of [Domain Trust Discovery](https://attack.mitre.org/techniques/T1482).(Citation: Microsoft GetAllTrustRelationships)


Domain or Tenant Policy Modification

Adversaries may modify the configuration settings of a domain or identity tenant to evade defenses and/or escalate privileges in centrally managed environments. Such services provide a centralized means of managing identity resources such as devices and accounts, and often include configuration settings that may apply between domains or tenants such as trust relationships, identity syncing, or identity federation.

Modifications to domain or tenant settings may include altering domain Group Policy Objects (GPOs) in Microsoft Active Directory (AD) or changing trust settings for domains, including federation trusts relationships between domains or tenants.

With sufficient permissions, adversaries can modify domain or tenant policy settings. Since configuration settings for these services apply to a large number of identity resources, there are a great number of potential attacks malicious outcomes that can stem from this abuse. Examples of such abuse include:

* modifying GPOs to push a malicious [Scheduled Task](https://attack.mitre.org/techniques/T1053/005) to computers throughout the domain environment(Citation: ADSecurity GPO Persistence 2016)(Citation: Wald0 Guide to GPOs)(Citation: Harmj0y Abusing GPO Permissions)
* modifying domain trusts to include an adversary-controlled domain, allowing adversaries to  forge access tokens that will subsequently be accepted by victim domain resources(Citation: Microsoft - Customer Guidance on Recent Nation-State Cyber Attacks)
* changing configuration settings within the AD environment to implement a [Rogue Domain Controller](https://attack.mitre.org/techniques/T1207).
* adding new, adversary-controlled federated identity providers to identity tenants, allowing adversaries to authenticate as any user managed by the victim tenant (Citation: Okta Cross-Tenant Impersonation 2023)

Adversaries may temporarily modify domain or tenant policy, carry out a malicious action(s), and then revert the change to remove suspicious indicators.

It may be possible to detect domain policy modifications using Windows event logs. Group policy modifications, for example, may be logged under a variety of Windows event IDs for modifying, creating, undeleting, moving, and deleting directory service objects (Event ID 5136, 5137, 5138, 5139, 5141 respectively). Monitor for modifications to domain trust settings, such as when a user or application modifies the federation settings on the domain or updates domain authentication from Managed to Federated via ActionTypes Set federation settings on domain and Set domain authentication.(Citation: Microsoft - Azure Sentinel ADFSDomainTrustMods)(Citation: Microsoft 365 Defender Solorigate) This may also include monitoring for Event ID 307 which can be correlated to relevant Event ID 510 with the same Instance ID for change details.(Citation: Sygnia Golden SAML)(Citation: CISA SolarWinds Cloud Detection)

Consider monitoring for commands/cmdlets and command-line arguments that may be leveraged to modify domain policy settings.(Citation: Microsoft - Update or Repair Federated domain) Some domain policy modifications, such as changes to federation settings, are likely to be rare.(Citation: Microsoft 365 Defender Solorigate)


Domain or Tenant Policy Modification: Group Policy Modification

Adversaries may modify Group Policy Objects (GPOs) to subvert the intended discretionary access controls for a domain, usually with the intention of escalating privileges on the domain. Group policy allows for centralized management of user and computer settings in Active Directory (AD). GPOs are containers for group policy settings made up of files stored within a predictable network path `\<DOMAIN>\SYSVOL\<DOMAIN>\Policies\`.(Citation: TechNet Group Policy Basics)(Citation: ADSecurity GPO Persistence 2016)

Like other objects in AD, GPOs have access controls associated with them. By default all user accounts in the domain have permission to read GPOs. It is possible to delegate GPO access control permissions, e.g. write access, to specific users or groups in the domain.

Malicious GPO modifications can be used to implement many other malicious behaviors such as [Scheduled Task/Job](https://attack.mitre.org/techniques/T1053), [Disable or Modify Tools](https://attack.mitre.org/techniques/T1562/001), [Ingress Tool Transfer](https://attack.mitre.org/techniques/T1105), [Create Account](https://attack.mitre.org/techniques/T1136), [Service Execution](https://attack.mitre.org/techniques/T1569/002),  and more.(Citation: ADSecurity GPO Persistence 2016)(Citation: Wald0 Guide to GPOs)(Citation: Harmj0y Abusing GPO Permissions)(Citation: Mandiant M Trends 2016)(Citation: Microsoft Hacking Team Breach) Since GPOs can control so many user and machine settings in the AD environment, there are a great number of potential attacks that can stem from this GPO abuse.(Citation: Wald0 Guide to GPOs)

For example, publicly available scripts such as New-GPOImmediateTask can be leveraged to automate the creation of a malicious [Scheduled Task/Job](https://attack.mitre.org/techniques/T1053) by modifying GPO settings, in this case modifying <GPO_PATH>\Machine\Preferences\ScheduledTasks\ScheduledTasks.xml.(Citation: Wald0 Guide to GPOs)(Citation: Harmj0y Abusing GPO Permissions) In some cases an adversary might modify specific user rights like SeEnableDelegationPrivilege, set in <GPO_PATH>\MACHINE\Microsoft\Windows NT\SecEdit\GptTmpl.inf, to achieve a subtle AD backdoor with complete control of the domain because the user account under the adversary's control would then be able to modify GPOs.(Citation: Harmj0y SeEnableDelegationPrivilege Right)

It is possible to detect GPO modifications by monitoring directory service changes using Windows event logs. Several events may be logged for such GPO modifications, including:

* Event ID 5136 - A directory service object was modified
* Event ID 5137 - A directory service object was created
* Event ID 5138 - A directory service object was undeleted
* Event ID 5139 - A directory service object was moved
* Event ID 5141 - A directory service object was deleted

GPO abuse will often be accompanied by some other behavior such as [Scheduled Task/Job](https://attack.mitre.org/techniques/T1053), which will have events associated with it to detect. Subsequent permission value modifications, like those to SeEnableDelegationPrivilege, can also be searched for in events associated with privileges assigned to new logons (Event ID 4672) and assignment of user rights (Event ID 4704).


Domain or Tenant Policy Modification: Trust Modification

Adversaries may add new domain trusts, modify the properties of existing domain trusts, or otherwise change the configuration of trust relationships between domains and tenants to evade defenses and/or elevate privileges.Trust details, such as whether or not user identities are federated, allow authentication and authorization properties to apply between domains or tenants for the purpose of accessing shared resources.(Citation: Microsoft - Azure AD Federation) These trust objects may include accounts, credentials, and other authentication material applied to servers, tokens, and domains.

Manipulating these trusts may allow an adversary to escalate privileges and/or evade defenses by modifying settings to add objects which they control. For example, in Microsoft Active Directory (AD) environments, this may be used to forge [SAML Tokens](https://attack.mitre.org/techniques/T1606/002) without the need to compromise the signing certificate to forge new credentials. Instead, an adversary can manipulate domain trusts to add their own signing certificate. An adversary may also convert an AD domain to a federated domain using Active Directory Federation Services (AD FS), which may enable malicious trust modifications such as altering the claim issuance rules to log in any valid set of credentials as a specified user.(Citation: AADInternals zure AD Federated Domain)

An adversary may also add a new federated identity provider to an identity tenant such as Okta, which may enable the adversary to authenticate as any user of the tenant.(Citation: Okta Cross-Tenant Impersonation 2023)

Monitor for modifications to domain trust settings, such as when a user or application modifies the federation settings on the domain or updates domain authentication from Managed to Federated via ActionTypes Set federation settings on domain and Set domain authentication.(Citation: Microsoft - Azure Sentinel ADFSDomainTrustMods) This may also include monitoring for Event ID 307 which can be correlated to relevant Event ID 510 with the same Instance ID for change details.(Citation: Sygnia Golden SAML)(Citation: CISA SolarWinds Cloud Detection)

Monitor for PowerShell commands such as: Update-MSOLFederatedDomain –DomainName: "Federated Domain Name", or Update-MSOLFederatedDomain –DomainName: "Federated Domain Name" –supportmultipledomain.(Citation: Microsoft - Update or Repair Federated domain)


Drive-by Compromise

Adversaries may gain access to a system through a user visiting a website over the normal course of browsing. With this technique, the user's web browser is typically targeted for exploitation, but adversaries may also use compromised websites for non-exploitation behavior such as acquiring [Application Access Token](https://attack.mitre.org/techniques/T1550/001).

Multiple ways of delivering exploit code to a browser exist (i.e., [Drive-by Target](https://attack.mitre.org/techniques/T1608/004)), including:

* A legitimate website is compromised where adversaries have injected some form of malicious code such as JavaScript, iFrames, and cross-site scripting
* Script files served to a legitimate website from a publicly writeable cloud storage bucket are modified by an adversary
* Malicious ads are paid for and served through legitimate ad providers (i.e., [Malvertising](https://attack.mitre.org/techniques/T1583/008))
* Built-in web application interfaces are leveraged for the insertion of any other kind of object that can be used to display web content or contain a script that executes on the visiting client (e.g. forum posts, comments, and other user controllable web content).

Often the website used by an adversary is one visited by a specific community, such as government, a particular industry, or region, where the goal is to compromise a specific user or set of users based on a shared interest. This kind of targeted campaign is often referred to a strategic web compromise or watering hole attack. There are several known examples of this occurring.(Citation: Shadowserver Strategic Web Compromise)

Typical drive-by compromise process:

1. A user visits a website that is used to host the adversary controlled content.
2. Scripts automatically execute, typically searching versions of the browser and plugins for a potentially vulnerable version.
    * The user may be required to assist in this process by enabling scripting or active website components and ignoring warning dialog boxes.
3. Upon finding a vulnerable version, exploit code is delivered to the browser.
4. If exploitation is successful, then it will give the adversary code execution on the user's system unless other protections are in place.
    * In some cases a second visit to the website after the initial scan is required before exploit code is delivered.

Unlike [Exploit Public-Facing Application](https://attack.mitre.org/techniques/T1190), the focus of this technique is to exploit software on a client endpoint upon visiting a website. This will commonly give an adversary access to systems on the internal network instead of external systems that may be in a DMZ.

Adversaries may also use compromised websites to deliver a user to a malicious application designed to [Steal Application Access Token](https://attack.mitre.org/techniques/T1528)s, like OAuth tokens, to gain access to protected applications and information. These malicious applications have been delivered through popups on legitimate websites.(Citation: Volexity OceanLotus Nov 2017)

Firewalls and proxies can inspect URLs for potentially known-bad domains or parameters. They can also do reputation-based analytics on websites and their requested resources such as how old a domain is, who it's registered to, if it's on a known bad list, or how many other users have connected to it before.

Network intrusion detection systems, sometimes with SSL/TLS inspection, can be used to look for known malicious scripts (recon, heap spray, and browser identification scripts have been frequently reused), common script obfuscation, and exploit code.

Detecting compromise based on the drive-by exploit from a legitimate website may be difficult. Also look for behavior on the endpoint system that might indicate successful compromise, such as abnormal behavior of browser processes. This could include suspicious files written to disk, evidence of [Process Injection](https://attack.mitre.org/techniques/T1055) for attempts to hide execution, evidence of Discovery, or other unusual network traffic that may indicate additional tools transferred to the system.


Dynamic Resolution

Adversaries may dynamically establish connections to command and control infrastructure to evade common detections and remediations. This may be achieved by using malware that shares a common algorithm with the infrastructure the adversary uses to receive the malware's communications. These calculations can be used to dynamically adjust parameters such as the domain name, IP address, or port number the malware uses for command and control.

Adversaries may use dynamic resolution for the purpose of [Fallback Channels](https://attack.mitre.org/techniques/T1008). When contact is lost with the primary command and control server malware may employ dynamic resolution as a means to reestablishing command and control.(Citation: Talos CCleanup 2017)(Citation: FireEye POSHSPY April 2017)(Citation: ESET Sednit 2017 Activity)

Detecting dynamically generated C2 can be challenging due to the number of different algorithms, constantly evolving malware families, and the increasing complexity of the algorithms. There are multiple approaches to detecting a pseudo-randomly generated domain name, including using frequency analysis, Markov chains, entropy, proportion of dictionary words, ratio of vowels to other characters, and more (Citation: Data Driven Security DGA). CDN domains may trigger these detections due to the format of their domain names. In addition to detecting algorithm generated domains based on the name, another more general approach for detecting a suspicious domain is to check for recently registered names or for rarely visited domains.


Dynamic Resolution: DNS Calculation

Adversaries may perform calculations on addresses returned in DNS results to determine which port and IP address to use for command and control, rather than relying on a predetermined port number or the actual returned IP address. A IP and/or port number calculation can be used to bypass egress filtering on a C2 channel.(Citation: Meyers Numbered Panda)

One implementation of [DNS Calculation](https://attack.mitre.org/techniques/T1568/003) is to take the first three octets of an IP address in a DNS response and use those values to calculate the port for command and control traffic.(Citation: Meyers Numbered Panda)(Citation: Moran 2014)(Citation: Rapid7G20Espionage)

Detection for this technique is difficult because it would require knowledge of the specific implementation of the port calculation algorithm. Detection may be possible by analyzing DNS records if the algorithm is known.


Dynamic Resolution: Domain Generation Algorithms

Adversaries may make use of Domain Generation Algorithms (DGAs) to dynamically identify a destination domain for command and control traffic rather than relying on a list of static IP addresses or domains. This has the advantage of making it much harder for defenders to block, track, or take over the command and control channel, as there potentially could be thousands of domains that malware can check for instructions.(Citation: Cybereason Dissecting DGAs)(Citation: Cisco Umbrella DGA)(Citation: Unit 42 DGA Feb 2019)

DGAs can take the form of apparently random or “gibberish” strings (ex: istgmxdejdnxuyla.ru) when they construct domain names by generating each letter. Alternatively, some DGAs employ whole words as the unit by concatenating words together instead of letters (ex: cityjulydish.net). Many DGAs are time-based, generating a different domain for each time period (hourly, daily, monthly, etc). Others incorporate a seed value as well to make predicting future domains more difficult for defenders.(Citation: Cybereason Dissecting DGAs)(Citation: Cisco Umbrella DGA)(Citation: Talos CCleanup 2017)(Citation: Akamai DGA Mitigation)

Adversaries may use DGAs for the purpose of [Fallback Channels](https://attack.mitre.org/techniques/T1008). When contact is lost with the primary command and control server malware may employ a DGA as a means to reestablishing command and control.(Citation: Talos CCleanup 2017)(Citation: FireEye POSHSPY April 2017)(Citation: ESET Sednit 2017 Activity)

Detecting dynamically generated domains can be challenging due to the number of different DGA algorithms, constantly evolving malware families, and the increasing complexity of the algorithms. There is a myriad of approaches for detecting a pseudo-randomly generated domain name, including using frequency analysis, Markov chains, entropy, proportion of dictionary words, ratio of vowels to other characters, and more.(Citation: Data Driven Security DGA) CDN domains may trigger these detections due to the format of their domain names. In addition to detecting a DGA domain based on the name, another more general approach for detecting a suspicious domain is to check for recently registered names or for rarely visited domains.

Machine learning approaches to detecting DGA domains have been developed and have seen success in applications. One approach is to use N-Gram methods to determine a randomness score for strings used in the domain name. If the randomness score is high, and the domains are not whitelisted (CDN, etc), then it may be determined if a domain is related to a legitimate host or DGA.(Citation: Pace University Detecting DGA May 2017) Another approach is to use deep learning to classify domains as DGA-generated.(Citation: Elastic Predicting DGA)


Dynamic Resolution: Fast Flux DNS

Adversaries may use Fast Flux DNS to hide a command and control channel behind an array of rapidly changing IP addresses linked to a single domain resolution. This technique uses a fully qualified domain name, with multiple IP addresses assigned to it which are swapped with high frequency, using a combination of round robin IP addressing and short Time-To-Live (TTL) for a DNS resource record.(Citation: MehtaFastFluxPt1)(Citation: MehtaFastFluxPt2)(Citation: Fast Flux - Welivesecurity)

The simplest, "single-flux" method, involves registering and de-registering an addresses as part of the DNS A (address) record list for a single DNS name. These registrations have a five-minute average lifespan, resulting in a constant shuffle of IP address resolution.(Citation: Fast Flux - Welivesecurity)

In contrast, the "double-flux" method registers and de-registers an address as part of the DNS Name Server record list for the DNS zone, providing additional resilience for the connection. With double-flux additional hosts can act as a proxy to the C2 host, further insulating the true source of the C2 channel.

In general, detecting usage of fast flux DNS is difficult due to web traffic load balancing that services client requests quickly. In single flux cases only IP addresses change for static domain names. In double flux cases, nothing is static. Defenders such as domain registrars and service providers are likely in the best position for detection.


Email Collection

Adversaries may target user email to collect sensitive information. Emails may contain sensitive data, including trade secrets or personal information, that can prove valuable to adversaries. Adversaries can collect or forward email from mail servers or clients.

There are likely a variety of ways an adversary could collect email from a target, each with a different mechanism for detection.

File access of local system email files for Exfiltration, unusual processes connecting to an email server within a network, or unusual access patterns or authentication attempts on a public-facing webmail server may all be indicators of malicious activity.

Monitor processes and command-line arguments for actions that could be taken to gather local email files. Remote access tools with built-in features may interact directly with the Windows API to gather information. Information may also be acquired through Windows system management tools such as [Windows Management Instrumentation](https://attack.mitre.org/techniques/T1047) and [PowerShell](https://attack.mitre.org/techniques/T1059/001).

Detection is challenging because all messages forwarded because of an auto-forwarding rule have the same presentation as a manually forwarded message. It is also possible for the user to not be aware of the addition of such an auto-forwarding rule and not suspect that their account has been compromised; email-forwarding rules alone will not affect the normal usage patterns or operations of the email account.

Auto-forwarded messages generally contain specific detectable artifacts that may be present in the header; such artifacts would be platform-specific. Examples include X-MS-Exchange-Organization-AutoForwarded set to true, X-MailFwdBy and X-Forwarded-To. The forwardingSMTPAddress parameter used in a forwarding process that is managed by administrators and not by user actions. All messages for the mailbox are forwarded to the specified SMTP address. However, unlike typical client-side rules, the message does not appear as forwarded in the mailbox; it appears as if it were sent directly to the specified destination mailbox.(Citation: Microsoft Tim McMichael Exchange Mail Forwarding 2) High volumes of emails that bear the X-MS-Exchange-Organization-AutoForwarded header (indicating auto-forwarding) without a corresponding number of emails that match the appearance of a forwarded message may indicate that further investigation is needed at the administrator level rather than user-level.


Email Collection: Email Forwarding Rule

Adversaries may setup email forwarding rules to collect sensitive information. Adversaries may abuse email forwarding rules to monitor the activities of a victim, steal information, and further gain intelligence on the victim or the victim’s organization to use as part of further exploits or operations.(Citation: US-CERT TA18-068A 2018) Furthermore, email forwarding rules can allow adversaries to maintain persistent access to victim's emails even after compromised credentials are reset by administrators.(Citation: Pfammatter - Hidden Inbox Rules) Most email clients allow users to create inbox rules for various email functions, including forwarding to a different recipient. These rules may be created through a local email application, a web interface, or by command-line interface. Messages can be forwarded to internal or external recipients, and there are no restrictions limiting the extent of this rule. Administrators may also create forwarding rules for user accounts with the same considerations and outcomes.(Citation: Microsoft Tim McMichael Exchange Mail Forwarding 2)(Citation: Mac Forwarding Rules)

Any user or administrator within the organization (or adversary with valid credentials) can create rules to automatically forward all received messages to another recipient, forward emails to different locations based on the sender, and more. Adversaries may also hide the rule by making use of the Microsoft Messaging API (MAPI) to modify the rule properties, making it hidden and not visible from Outlook, OWA or most Exchange Administration tools.(Citation: Pfammatter - Hidden Inbox Rules)

In some environments, administrators may be able to enable email forwarding rules that operate organization-wide rather than on individual inboxes. For example, Microsoft Exchange supports transport rules that evaluate all mail an organization receives against user-specified conditions, then performs a user-specified action on mail that adheres to those conditions.(Citation: Microsoft Mail Flow Rules 2023) Adversaries that abuse such features may be able to enable forwarding on all or specific mail an organization receives.

Detection is challenging because all messages forwarded because of an auto-forwarding rule have the same presentation as a manually forwarded message. It is also possible for the user to not be aware of the addition of such an auto-forwarding rule and not suspect that their account has been compromised; email-forwarding rules alone will not affect the normal usage patterns or operations of the email account. This is especially true in cases with hidden auto-forwarding rules. This makes it only possible to reliably detect the existence of a hidden auto-forwarding rule by examining message tracking logs or by using a MAPI editor to notice the modified rule property values.(Citation: Pfammatter - Hidden Inbox Rules)

Auto-forwarded messages generally contain specific detectable artifacts that may be present in the header; such artifacts would be platform-specific. Examples include `X-MS-Exchange-Organization-AutoForwarded` set to true, `X-MailFwdBy` and `X-Forwarded-To`. The `forwardingSMTPAddress` parameter used in a forwarding process that is managed by administrators and not by user actions. All messages for the mailbox are forwarded to the specified SMTP address. However, unlike typical client-side rules, the message does not appear as forwarded in the mailbox; it appears as if it were sent directly to the specified destination mailbox.(Citation: Microsoft Tim McMichael Exchange Mail Forwarding 2) High volumes of emails that bear the `X-MS-Exchange-Organization-AutoForwarded` header (indicating auto-forwarding) without a corresponding number of emails that match the appearance of a forwarded message may indicate that further investigation is needed at the administrator level rather than user-level.


Email Collection: Local Email Collection

Adversaries may target user email on local systems to collect sensitive information. Files containing email data can be acquired from a user’s local system, such as Outlook storage or cache files.

Outlook stores data locally in offline data files with an extension of .ost. Outlook 2010 and later supports .ost file sizes up to 50GB, while earlier versions of Outlook support up to 20GB.(Citation: Outlook File Sizes) IMAP accounts in Outlook 2013 (and earlier) and POP accounts use Outlook Data Files (.pst) as opposed to .ost, whereas IMAP accounts in Outlook 2016 (and later) use .ost files. Both types of Outlook data files are typically stored in `C:\Users\<username>\Documents\Outlook Files` or `C:\Users\<username>\AppData\Local\Microsoft\Outlook`.(Citation: Microsoft Outlook Files)

Monitor processes and command-line arguments for actions that could be taken to gather local email files. Monitor for unusual processes accessing local email files. Remote access tools with built-in features may interact directly with the Windows API to gather information. Information may also be acquired through Windows system management tools such as [Windows Management Instrumentation](https://attack.mitre.org/techniques/T1047) and [PowerShell](https://attack.mitre.org/techniques/T1059/001).


Email Collection: Remote Email Collection

Adversaries may target an Exchange server, Office 365, or Google Workspace to collect sensitive information. Adversaries may leverage a user's credentials and interact directly with the Exchange server to acquire information from within a network. Adversaries may also access externally facing Exchange services, Office 365, or Google Workspace to access email using credentials or access tokens. Tools such as [MailSniper](https://attack.mitre.org/software/S0413) can be used to automate searches for specific keywords.

Monitor for unusual login activity from unknown or abnormal locations, especially for privileged accounts (ex: Exchange administrator account).


Encrypted Channel

Adversaries may employ an encryption algorithm to conceal command and control traffic rather than relying on any inherent protections provided by a communication protocol. Despite the use of a secure algorithm, these implementations may be vulnerable to reverse engineering if secret keys are encoded and/or generated within malware samples/configuration files.

SSL/TLS inspection is one way of detecting command and control traffic within some encrypted communication channels.(Citation: SANS Decrypting SSL) SSL/TLS inspection does come with certain risks that should be considered before implementing to avoid potential security issues such as incomplete certificate validation.(Citation: SEI SSL Inspection Risks)

In general, analyze network data for uncommon data flows (e.g., a client sending significantly more data than it receives from a server). Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious. Analyze packet contents to detect communications that do not follow the expected protocol behavior for the port that is being used.(Citation: University of Birmingham C2)


Encrypted Channel: Asymmetric Cryptography

Adversaries may employ a known asymmetric encryption algorithm to conceal command and control traffic rather than relying on any inherent protections provided by a communication protocol. Asymmetric cryptography, also known as public key cryptography, uses a keypair per party: one public that can be freely distributed, and one private. Due to how the keys are generated, the sender encrypts data with the receiver’s public key and the receiver decrypts the data with their private key. This ensures that only the intended recipient can read the encrypted data. Common public key encryption algorithms include RSA and ElGamal.

For efficiency, many protocols (including SSL/TLS) use symmetric cryptography once a connection is established, but use asymmetric cryptography to establish or transmit a key. As such, these protocols are classified as [Asymmetric Cryptography](https://attack.mitre.org/techniques/T1573/002).


Encrypted Channel: Symmetric Cryptography

Adversaries may employ a known symmetric encryption algorithm to conceal command and control traffic rather than relying on any inherent protections provided by a communication protocol. Symmetric encryption algorithms use the same key for plaintext encryption and ciphertext decryption. Common symmetric encryption algorithms include AES, DES, 3DES, Blowfish, and RC4.

With symmetric encryption, it may be possible to obtain the algorithm and key from samples and use them to decode network traffic to detect malware communications signatures.

In general, analyze network data for uncommon data flows (e.g., a client sending significantly more data than it receives from a server). Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious. Analyze packet contents to detect communications that do not follow the expected protocol behavior for the port that is being used.(Citation: University of Birmingham C2)


Endpoint Denial of Service

Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users. Endpoint DoS can be performed by exhausting the system resources those services are hosted on or exploiting the system to cause a persistent crash condition. Example services include websites, email services, DNS, and web-based applications. Adversaries have been observed conducting DoS attacks for political purposes(Citation: FireEye OpPoisonedHandover February 2016) and to support other malicious activities, including distraction(Citation: FSISAC FraudNetDoS September 2012), hacktivism, and extortion.(Citation: Symantec DDoS October 2014)

An Endpoint DoS denies the availability of a service without saturating the network used to provide access to the service. Adversaries can target various layers of the application stack that is hosted on the system used to provide the service. These layers include the Operating Systems (OS), server applications such as web servers, DNS servers, databases, and the (typically web-based) applications that sit on top of them. Attacking each layer requires different techniques that take advantage of bottlenecks that are unique to the respective components. A DoS attack may be generated by a single system or multiple systems spread across the internet, which is commonly referred to as a distributed DoS (DDoS).

To perform DoS attacks against endpoint resources, several aspects apply to multiple methods, including IP address spoofing and botnets.

Adversaries may use the original IP address of an attacking system, or spoof the source IP address to make the attack traffic more difficult to trace back to the attacking system or to enable reflection. This can increase the difficulty defenders have in defending against the attack by reducing or eliminating the effectiveness of filtering by the source address on network defense devices.

Botnets are commonly used to conduct DDoS attacks against networks and services. Large botnets can generate a significant amount of traffic from systems spread across the global internet. Adversaries may have the resources to build out and control their own botnet infrastructure or may rent time on an existing botnet to conduct an attack. In some of the worst cases for DDoS, so many systems are used to generate requests that each one only needs to send out a small amount of traffic to produce enough volume to exhaust the target's resources. In such circumstances, distinguishing DDoS traffic from legitimate clients becomes exceedingly difficult. Botnets have been used in some of the most high-profile DDoS attacks, such as the 2012 series of incidents that targeted major US banks.(Citation: USNYAG IranianBotnet March 2016)

In cases where traffic manipulation is used, there may be points in the global network (such as high traffic gateway routers) where packets can be altered and cause legitimate clients to execute code that directs network packets toward a target in high volume. This type of capability was previously used for the purposes of web censorship where client HTTP traffic was modified to include a reference to JavaScript that generated the DDoS code to overwhelm target web servers.(Citation: ArsTechnica Great Firewall of China)

For attacks attempting to saturate the providing network, see [Network Denial of Service](https://attack.mitre.org/techniques/T1498).

Detection of Endpoint DoS can sometimes be achieved before the effect is sufficient to cause significant impact to the availability of the service, but such response time typically requires very aggressive monitoring and responsiveness. Typical network throughput monitoring tools such as netflow, SNMP, and custom scripts can be used to detect sudden increases in circuit utilization.(Citation: Cisco DoSdetectNetflow) Real-time, automated, and qualitative study of the network traffic can identify a sudden surge in one type of protocol can be used to detect an attack as it starts.

In addition to network level detections, endpoint logging and instrumentation can be useful for detection. Attacks targeting web applications may generate logs in the web server, application server, and/or database server that can be used to identify the type of attack, possibly before the impact is felt.

Externally monitor the availability of services that may be targeted by an Endpoint DoS.


Endpoint Denial of Service: Application Exhaustion Flood

Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications. For example, specific features in web applications may be highly resource intensive. Repeated requests to those features may be able to exhaust system resources and deny access to the application or the server itself.(Citation: Arbor AnnualDoSreport Jan 2018)

Detection of Endpoint DoS can sometimes be achieved before the effect is sufficient to cause significant impact to the availability of the service, but such response time typically requires very aggressive monitoring and responsiveness. Typical network throughput monitoring tools such as netflow, SNMP, and custom scripts can be used to detect sudden increases in circuit utilization.(Citation: Cisco DoSdetectNetflow) Real-time, automated, and qualitative study of the network traffic can identify a sudden surge in one type of protocol can be used to detect an attack as it starts.

In addition to network level detections, endpoint logging and instrumentation can be useful for detection. Attacks targeting web applications may generate logs in the web server, application server, and/or database server that can be used to identify the type of attack, possibly before the impact is felt.


Endpoint Denial of Service: Application or System Exploitation

Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users. (Citation: Sucuri BIND9 August 2015) Some systems may automatically restart critical applications and services when crashes occur, but they can likely be re-exploited to cause a persistent denial of service (DoS) condition.

Adversaries may exploit known or zero-day vulnerabilities to crash applications and/or systems, which may also lead to dependent applications and/or systems to be in a DoS condition. Crashed or restarted applications or systems may also have other effects such as [Data Destruction](https://attack.mitre.org/techniques/T1485), [Firmware Corruption](https://attack.mitre.org/techniques/T1495), [Service Stop](https://attack.mitre.org/techniques/T1489) etc. which may further cause a DoS condition and deny availability to critical information, applications and/or systems.

Attacks targeting web applications may generate logs in the web server, application server, and/or database server that can be used to identify the type of attack. Externally monitor the availability of services that may be targeted by an Endpoint DoS.


Endpoint Denial of Service: OS Exhaustion Flood

Adversaries may launch a denial of service (DoS) attack targeting an endpoint's operating system (OS). A system's OS is responsible for managing the finite resources as well as preventing the entire system from being overwhelmed by excessive demands on its capacity. These attacks do not need to exhaust the actual resources on a system; the attacks may simply exhaust the limits and available resources that an OS self-imposes.

Different ways to achieve this exist, including TCP state-exhaustion attacks such as SYN floods and ACK floods.(Citation: Arbor AnnualDoSreport Jan 2018) With SYN floods, excessive amounts of SYN packets are sent, but the 3-way TCP handshake is never completed. Because each OS has a maximum number of concurrent TCP connections that it will allow, this can quickly exhaust the ability of the system to receive new requests for TCP connections, thus preventing access to any TCP service provided by the server.(Citation: Cloudflare SynFlood)

ACK floods leverage the stateful nature of the TCP protocol. A flood of ACK packets are sent to the target. This forces the OS to search its state table for a related TCP connection that has already been established. Because the ACK packets are for connections that do not exist, the OS will have to search the entire state table to confirm that no match exists. When it is necessary to do this for a large flood of packets, the computational requirements can cause the server to become sluggish and/or unresponsive, due to the work it must do to eliminate the rogue ACK packets. This greatly reduces the resources available for providing the targeted service.(Citation: Corero SYN-ACKflood)

Detection of Endpoint DoS can sometimes be achieved before the effect is sufficient to cause significant impact to the availability of the service, but such response time typically requires very aggressive monitoring and responsiveness. Typical network throughput monitoring tools such as netflow, SNMP, and custom scripts can be used to detect sudden increases in circuit utilization.(Citation: Cisco DoSdetectNetflow) Real-time, automated, and qualitative study of the network traffic can identify a sudden surge in one type of protocol can be used to detect an attack as it starts.


Endpoint Denial of Service: Service Exhaustion Flood

Adversaries may target the different network services provided by systems to conduct a denial of service (DoS). Adversaries often target the availability of DNS and web services, however others have been targeted as well.(Citation: Arbor AnnualDoSreport Jan 2018) Web server software can be attacked through a variety of means, some of which apply generally while others are specific to the software being used to provide the service.

One example of this type of attack is known as a simple HTTP flood, where an adversary sends a large number of HTTP requests to a web server to overwhelm it and/or an application that runs on top of it. This flood relies on raw volume to accomplish the objective, exhausting any of the various resources required by the victim software to provide the service.(Citation: Cloudflare HTTPflood)

Another variation, known as a SSL renegotiation attack, takes advantage of a protocol feature in SSL/TLS. The SSL/TLS protocol suite includes mechanisms for the client and server to agree on an encryption algorithm to use for subsequent secure connections. If SSL renegotiation is enabled, a request can be made for renegotiation of the crypto algorithm. In a renegotiation attack, the adversary establishes a SSL/TLS connection and then proceeds to make a series of renegotiation requests. Because the cryptographic renegotiation has a meaningful cost in computation cycles, this can cause an impact to the availability of the service when done in volume.(Citation: Arbor SSLDoS April 2012)


Escape to Host

Adversaries may break out of a container to gain access to the underlying host. This can allow an adversary access to other containerized resources from the host level or to the host itself. In principle, containerized resources should provide a clear separation of application functionality and be isolated from the host environment.(Citation: Docker Overview)

There are multiple ways an adversary may escape to a host environment. Examples include creating a container configured to mount the host’s filesystem using the bind parameter, which allows the adversary to drop payloads and execute control utilities such as cron on the host; utilizing a privileged container to run commands or load a malicious kernel module on the underlying host; or abusing system calls such as `unshare` and `keyctl` to escalate privileges and steal secrets.(Citation: Docker Bind Mounts)(Citation: Trend Micro Privileged Container)(Citation: Intezer Doki July 20)(Citation: Container Escape)(Citation: Crowdstrike Kubernetes Container Escape)(Citation: Keyctl-unmask)

Additionally, an adversary may be able to exploit a compromised container with a mounted container management socket, such as `docker.sock`, to break out of the container via a [Container Administration Command](https://attack.mitre.org/techniques/T1609).(Citation: Container Escape) Adversaries may also escape via [Exploitation for Privilege Escalation](https://attack.mitre.org/techniques/T1068), such as exploiting vulnerabilities in global symbolic links in order to access the root directory of a host machine.(Citation: Windows Server Containers Are Open)

Gaining access to the host may provide the adversary with the opportunity to achieve follow-on objectives, such as establishing persistence, moving laterally within the environment, accessing other containers running on the host, or setting up a command and control channel on the host.

Monitor for the deployment of suspicious or unknown container images and pods in your environment, particularly containers running as root. Additionally, monitor for unexpected usage of syscalls such as mount (as well as resulting process activity) that may indicate an attempt to escape from a privileged container to host. In Kubernetes, monitor for cluster-level events associated with changing containers' volume configurations.


Establish Accounts

Adversaries may create and cultivate accounts with services that can be used during targeting. Adversaries can create accounts that can be used to build a persona to further operations. Persona development consists of the development of public information, presence, history and appropriate affiliations. This development could be applied to social media, website, or other publicly available information that could be referenced and scrutinized for legitimacy over the course of an operation using that persona or identity.(Citation: NEWSCASTER2014)(Citation: BlackHatRobinSage)

For operations incorporating social engineering, the utilization of an online persona may be important. These personas may be fictitious or impersonate real people. The persona may exist on a single site or across multiple sites (ex: Facebook, LinkedIn, Twitter, Google, GitHub, Docker Hub, etc.). Establishing a persona may require development of additional documentation to make them seem real. This could include filling out profile information, developing social networks, or incorporating photos.(Citation: NEWSCASTER2014)(Citation: BlackHatRobinSage)

Establishing accounts can also include the creation of accounts with email providers, which may be directly leveraged for [Phishing for Information](https://attack.mitre.org/techniques/T1598) or [Phishing](https://attack.mitre.org/techniques/T1566).(Citation: Mandiant APT1) In addition, establishing accounts may allow adversaries to abuse free services, such as registering for trial periods to [Acquire Infrastructure](https://attack.mitre.org/techniques/T1583) for malicious purposes.(Citation: Free Trial PurpleUrchin)

Consider monitoring social media activity related to your organization. Suspicious activity may include personas claiming to work for your organization or recently created/modified accounts making numerous connection requests to accounts affiliated with your organization.

Much of this activity will take place outside the visibility of the target organization, making detection of this behavior difficult. Detection efforts may be focused on related stages of the adversary lifecycle, such as during Initial Access (ex: [Phishing](https://attack.mitre.org/techniques/T1566)).


Establish Accounts: Cloud Accounts

Adversaries may create accounts with cloud providers that can be used during targeting. Adversaries can use cloud accounts to further their operations, including leveraging cloud storage services such as Dropbox, MEGA, Microsoft OneDrive, or AWS S3 buckets for [Exfiltration to Cloud Storage](https://attack.mitre.org/techniques/T1567/002) or to [Upload Tool](https://attack.mitre.org/techniques/T1608/002)s. Cloud accounts can also be used in the acquisition of infrastructure, such as [Virtual Private Server](https://attack.mitre.org/techniques/T1583/003)s or [Serverless](https://attack.mitre.org/techniques/T1583/007) infrastructure. Establishing cloud accounts may allow adversaries to develop sophisticated capabilities without managing their own servers.(Citation: Awake Security C2 Cloud)

Creating [Cloud Accounts](https://attack.mitre.org/techniques/T1585/003) may also require adversaries to establish [Email Accounts](https://attack.mitre.org/techniques/T1585/002) to register with the cloud provider.

Much of this activity will take place outside the visibility of the target organization, making detection of this behavior difficult. Detection efforts may be focused on related stages of the adversary lifecycle, such as during exfiltration (ex: [Transfer Data to Cloud Account](https://attack.mitre.org/techniques/T1537)).


Establish Accounts: Email Accounts

Adversaries may create email accounts that can be used during targeting. Adversaries can use accounts created with email providers to further their operations, such as leveraging them to conduct [Phishing for Information](https://attack.mitre.org/techniques/T1598) or [Phishing](https://attack.mitre.org/techniques/T1566).(Citation: Mandiant APT1) Establishing email accounts may also allow adversaries to abuse free services – such as trial periods – to [Acquire Infrastructure](https://attack.mitre.org/techniques/T1583) for follow-on purposes.(Citation: Free Trial PurpleUrchin)

Adversaries may also take steps to cultivate a persona around the email account, such as through use of [Social Media Accounts](https://attack.mitre.org/techniques/T1585/001), to increase the chance of success of follow-on behaviors. Created email accounts can also be used in the acquisition of infrastructure (ex: [Domains](https://attack.mitre.org/techniques/T1583/001)).(Citation: Mandiant APT1)

To decrease the chance of physically tying back operations to themselves, adversaries may make use of disposable email services.(Citation: Trend Micro R980 2016)

Much of this activity will take place outside the visibility of the target organization, making detection of this behavior difficult. Detection efforts may be focused on related stages of the adversary lifecycle, such as during Initial Access (ex: [Phishing](https://attack.mitre.org/techniques/T1566)).


Establish Accounts: Social Media Accounts

Adversaries may create and cultivate social media accounts that can be used during targeting. Adversaries can create social media accounts that can be used to build a persona to further operations. Persona development consists of the development of public information, presence, history and appropriate affiliations.(Citation: NEWSCASTER2014)(Citation: BlackHatRobinSage)

For operations incorporating social engineering, the utilization of a persona on social media may be important. These personas may be fictitious or impersonate real people. The persona may exist on a single social media site or across multiple sites (ex: Facebook, LinkedIn, Twitter, etc.). Establishing a persona  on social media may require development of additional documentation to make them seem real. This could include filling out profile information, developing social networks, or incorporating photos.

Once a persona has been developed an adversary can use it to create connections to targets of interest. These connections may be direct or may include trying to connect through others.(Citation: NEWSCASTER2014)(Citation: BlackHatRobinSage) These accounts may be leveraged during other phases of the adversary lifecycle, such as during Initial Access (ex: [Spearphishing via Service](https://attack.mitre.org/techniques/T1566/003)).

Consider monitoring social media activity related to your organization. Suspicious activity may include personas claiming to work for your organization or recently created/modified accounts making numerous connection requests to accounts affiliated with your organization.

Detection efforts may be focused on related stages of the adversary lifecycle, such as during Initial Access (ex: [Spearphishing via Service](https://attack.mitre.org/techniques/T1566/003)).


Event Triggered Execution

Adversaries may establish persistence and/or elevate privileges using system mechanisms that trigger execution based on specific events. Various operating systems have means to monitor and subscribe to events such as logons or other user activity such as running specific applications/binaries. Cloud environments may also support various functions and services that monitor and can be invoked in response to specific cloud events.(Citation: Backdooring an AWS account)(Citation: Varonis Power Automate Data Exfiltration)(Citation: Microsoft DART Case Report 001)

Adversaries may abuse these mechanisms as a means of maintaining persistent access to a victim via repeatedly executing malicious code. After gaining access to a victim system, adversaries may create/modify event triggers to point to malicious content that will be executed whenever the event trigger is invoked.(Citation: FireEye WMI 2015)(Citation: Malware Persistence on OS X)(Citation: amnesia malware)

Since the execution can be proxied by an account with higher permissions, such as SYSTEM or service accounts, an adversary may be able to abuse these triggered execution mechanisms to escalate their privileges.

Monitoring for additions or modifications of mechanisms that could be used to trigger event-based execution, especially the addition of abnormal commands such as execution of unknown programs, opening network sockets, or reaching out across the network. Also look for changes that do not line up with updates, patches, or other planned administrative activity.

These mechanisms may vary by OS, but are typically stored in central repositories that store configuration information such as the Windows Registry, Common Information Model (CIM), and/or specific named files, the last of which can be hashed and compared to known good values.

Monitor for processes, API/System calls, and other common ways of manipulating these event repositories.

Tools such as Sysinternals Autoruns can be used to detect changes to execution triggers that could be attempts at persistence. Also look for abnormal process call trees for execution of other commands that could relate to Discovery actions or other techniques.

Monitor DLL loads by processes, specifically looking for DLLs that are not recognized or not normally loaded into a process. Look for abnormal process behavior that may be due to a process loading a malicious DLL. Data and events should not be viewed in isolation, but as part of a chain of behavior that could lead to other activities, such as making network connections for Command and Control, learning details about the environment through Discovery, and conducting Lateral Movement.