Track Common Adversary Tasks Performed Using AppleSeed

Adversaries may abuse PowerShell commands and scripts for execution. PowerShell is a powerful interactive command-line interface and scripting environment included in the Windows operating system. Adversaries can use PowerShell to perform a number of actions, including discovery of information and execution of code. Examples include the Start-Process cmdlet which can be used to run an executable and the Invoke-Command cmdlet which runs a command locally or on a remote computer (though administrator permissions are required to use PowerShell to connect to remote systems).

PowerShell may also be used to download and run executables from the Internet, which can be executed from disk or in memory without touching disk.

A number of PowerShell-based offensive testing tools are available, including Empire, PowerSploit, PoshC2, and PSAttack.

PowerShell commands/scripts can also be executed without directly invoking the powershell.exe binary through interfaces to PowerShell's underlying System.Management.Automation assembly DLL exposed through the .NET framework and Windows Common Language Interface (CLI).

Antivirus/Antimalware

Anti-virus can be used to automatically quarantine suspicious files.

Code Signing

Set PowerShell execution policy to execute only signed scripts.

Disable or Remove Feature or Program

It may be possible to remove PowerShell from systems when not needed, but a review should be performed to assess the impact to an environment, since it could be in use for many legitimate purposes and administrative functions.

Disable/restrict the WinRM Service to help prevent uses of PowerShell for remote execution.

Execution Prevention

Use application control where appropriate.

Privileged Account Management

When PowerShell is necessary, restrict PowerShell execution policy to administrators. Be aware that there are methods of bypassing the PowerShell execution policy, depending on environment configuration.

Monitoring the following activities in your Organization can help you detect this technique.

Command: Command Execution

Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)

If proper execution policy is set, adversaries will likely be able to define their own execution policy if they obtain administrator or system access, either through the Registry or at the command line. This change in policy on a system may be a way to detect malicious use of PowerShell. If PowerShell is not used in an environment, then simply looking for PowerShell execution may detect malicious activity. It is also beneficial to turn on PowerShell logging to gain increased fidelity in what occurs during execution (which is applied to .NET invocations).  PowerShell 5.0 introduced enhanced logging capabilities, and some of those features have since been added to PowerShell 4.0. Earlier versions of PowerShell do not have many logging features. An organization can gather PowerShell execution details in a data analytic platform to supplement it with other data.

Module: Module Load

Attaching a module into the memory of a process/program, typically to access shared resources/features provided by the module (ex: Sysmon EID 7)

Monitor for loading and/or execution of artifacts associated with PowerShell specific assemblies, such as System.Management.Automation.dll (especially to unusual process names/locations).

Process: Process Creation

Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)

Monitor for newly executed processes that may abuse PowerShell commands and scripts for execution.

Process: Process Metadata

Contextual data about a running process, which may include information such as environment variables, image name, user/owner, etc.

Consider monitoring for Windows event ID (EID) 400, which shows the version of PowerShell executing in the EngineVersion field (which may also be relevant to detecting a potential Downgrade Attack) as well as if PowerShell is running locally or remotely in the HostName field. Furthermore, EID 400 may indicate the start time and EID 403 indicates the end time of a PowerShell session.

Script: Script Execution

Launching a list of commands through a script file (ex: Windows EID 4104)

Monitor for any attempts to enable scripts running on a system would be considered suspicious. If scripts are not commonly used on a system, but enabled, scripts running out of cycle from patching or other administrator functions are suspicious. Scripts should be captured from the file system when possible to determine their actions and intent.

Adversaries may interact with the native OS application programming interface (API) to execute behaviors. Native APIs provide a controlled means of calling low-level OS services within the kernel, such as those involving hardware/devices, memory, and processes. These native APIs are leveraged by the OS during system boot (when other system components are not yet initialized) as well as carrying out tasks and requests during routine operations.

Native API functions (such as NtCreateProcess) may be directed invoked via system calls / syscalls, but these features are also often exposed to user-mode applications via interfaces and libraries. For example, functions such as the Windows API CreateProcess() or GNU fork() will allow programs and scripts to start other processes. This may allow API callers to execute a binary, run a CLI command, load modules, etc. as thousands of similar API functions exist for various system operations.

Higher level software frameworks, such as Microsoft .NET and macOS Cocoa, are also available to interact with native APIs. These frameworks typically provide language wrappers/abstractions to API functionalities and are designed for ease-of-use/portability of code.

Adversaries may abuse these OS API functions as a means of executing behaviors. Similar to Command and Scripting Interpreter, the native API and its hierarchy of interfaces provide mechanisms to interact with and utilize various components of a victimized system. While invoking API functions, adversaries may also attempt to bypass defensive tools (ex: unhooking monitored functions via Disable or Modify Tools).

Behavior Prevention on Endpoint

On Windows 10, enable Attack Surface Reduction (ASR) rules to prevent Office VBA macros from calling Win32 APIs. 

Execution Prevention

Identify and block potentially malicious software executed that may be executed through this technique by using application control  tools, like Windows Defender Application Control, AppLocker, or Software Restriction Policies  where appropriate.

Monitoring the following activities in your Organization can help you detect this technique.

Module: Module Load

Attaching a module into the memory of a process/program, typically to access shared resources/features provided by the module (ex: Sysmon EID 7)

Monitor DLL/PE file events, specifically creation of these binary files as well as the loading of DLLs into processes. Utilization of the Windows APIs may involve processes loading/accessing system DLLs associated with providing called functions (ex: ntdll.dll, kernel32.dll, advapi32.dll, user32.dll, and gdi32.dll). Monitoring for DLL loads, especially to abnormal/unusual or potentially malicious processes, may indicate abuse of the Windows API. Though noisy, this data can be combined with other indicators to identify adversary activity.

Process: OS API Execution

Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)

Monitoring API calls may generate a significant amount of data and may not be useful for defense unless collected under specific circumstances, since benign use of API functions are common and may be difficult to distinguish from malicious behavior. Correlation of other events with behavior surrounding API function calls using API monitoring will provide additional context to an event that may assist in determining if it is due to malicious behavior. Correlation of activity by process lineage by process ID may be sufficient.

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the "run keys" in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account's associated permissions level.

Placing a program within a startup folder will also cause that program to execute when a user logs in. There is a startup folder location for individual user accounts as well as a system-wide startup folder that will be checked regardless of which user account logs in. The startup folder path for the current user is C:\Users\[Username]\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup. The startup folder path for all users is C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp.

The following run keys are created by default on Windows systems:

• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
• HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
• HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce

Run keys may exist under multiple hives. The HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnceEx is also available but is not created by default on Windows Vista and newer. Registry run key entries can reference programs directly or list them as a dependency. For example, it is possible to load a DLL at logon using a "Depend" key with RunOnceEx: reg add HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnceEx\0001\Depend /v 1 /d "C:\temp\evil[.]dll" 

The following Registry keys can be used to set startup folder items for persistence:

• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders

The following Registry keys can control automatic startup of services during boot:

• HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServicesOnce
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunServicesOnceHKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServices
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunServices

Using policy settings to specify startup programs creates corresponding values in either of two Registry keys:

• HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run

The Winlogon key controls actions that occur when a user logs on to a computer running Windows 7. Most of these actions are under the control of the operating system, but you can also add custom actions here. The HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit and HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell subkeys can automatically launch programs.

Programs listed in the load value of the registry key HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows run when any user logs on.

By default, the multistring BootExecute value of the registry key HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager is set to autocheck autochk *. This value causes Windows, at startup, to check the file-system integrity of the hard disks if the system has been shut down abnormally. Adversaries can add other programs or processes to this registry value which will automatically launch at boot.

Adversaries can use these configuration locations to execute malware, such as remote access tools, to maintain persistence through system reboots. Adversaries may also use Masquerading to make the Registry entries look as if they are associated with legitimate programs.

This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.

Monitoring the following activities in your Organization can help you detect this technique.

Command: Command Execution

Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)

Monitor executed commands and arguments that may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key.

File: File Modification

Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)

Monitor the start folder for additions or changes. Tools such as Sysinternals Autoruns may also be used to detect system changes that could be attempts at persistence, including the startup folders.

Windows Registry: Windows Registry Key Creation

Initial construction of a new Registry Key (ex: Windows EID 4656 or Sysmon EID 12)

Monitor for newly created windows registry keys that may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key.

Windows Registry: Windows Registry Key Modification

Changes made to a Registry Key and/or Key value (ex: Windows EID 4657 or Sysmon EID 13|14)

Monitor Registry for changes to run keys that do not correlate with known software, patch cycles, etc. Tools such as Sysinternals Autoruns may also be used to detect system changes that could be attempts at persistence, including listing the run keys' Registry locations.

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the "run keys" in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account's associated permissions level.

Placing a program within a startup folder will also cause that program to execute when a user logs in. There is a startup folder location for individual user accounts as well as a system-wide startup folder that will be checked regardless of which user account logs in. The startup folder path for the current user is C:\Users\[Username]\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup. The startup folder path for all users is C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp.

The following run keys are created by default on Windows systems:

• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
• HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
• HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce

Run keys may exist under multiple hives. The HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnceEx is also available but is not created by default on Windows Vista and newer. Registry run key entries can reference programs directly or list them as a dependency. For example, it is possible to load a DLL at logon using a "Depend" key with RunOnceEx: reg add HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnceEx\0001\Depend /v 1 /d "C:\temp\evil[.]dll" 

The following Registry keys can be used to set startup folder items for persistence:

• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders

The following Registry keys can control automatic startup of services during boot:

• HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServicesOnce
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunServicesOnceHKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServices
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunServices

Using policy settings to specify startup programs creates corresponding values in either of two Registry keys:

• HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run

The Winlogon key controls actions that occur when a user logs on to a computer running Windows 7. Most of these actions are under the control of the operating system, but you can also add custom actions here. The HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit and HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell subkeys can automatically launch programs.

Programs listed in the load value of the registry key HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows run when any user logs on.

By default, the multistring BootExecute value of the registry key HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager is set to autocheck autochk *. This value causes Windows, at startup, to check the file-system integrity of the hard disks if the system has been shut down abnormally. Adversaries can add other programs or processes to this registry value which will automatically launch at boot.

Adversaries can use these configuration locations to execute malware, such as remote access tools, to maintain persistence through system reboots. Adversaries may also use Masquerading to make the Registry entries look as if they are associated with legitimate programs.

This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.

Monitoring the following activities in your Organization can help you detect this technique.

Command: Command Execution

Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)

Monitor executed commands and arguments that may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key.

File: File Modification

Changes made to a file, or its access permissions and attributes, typically to alter the contents of the targeted file (ex: Windows EID 4670 or Sysmon EID 2)

Monitor the start folder for additions or changes. Tools such as Sysinternals Autoruns may also be used to detect system changes that could be attempts at persistence, including the startup folders.

Windows Registry: Windows Registry Key Creation

Initial construction of a new Registry Key (ex: Windows EID 4656 or Sysmon EID 12)

Monitor for newly created windows registry keys that may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key.

Windows Registry: Windows Registry Key Modification

Changes made to a Registry Key and/or Key value (ex: Windows EID 4657 or Sysmon EID 13|14)

Monitor Registry for changes to run keys that do not correlate with known software, patch cycles, etc. Tools such as Sysinternals Autoruns may also be used to detect system changes that could be attempts at persistence, including listing the run keys' Registry locations.

Adversaries may perform software packing or virtual machine software protection to conceal their code. Software packing is a method of compressing or encrypting an executable. Packing an executable changes the file signature in an attempt to avoid signature-based detection. Most decompression techniques decompress the executable code in memory. Virtual machine software protection translates an executable's original code into a special format that only a special virtual machine can run. A virtual machine is then called to run this code.

Utilities used to perform software packing are called packers. Example packers are MPRESS and UPX. A more comprehensive list of known packers is available, but adversaries may create their own packing techniques that do not leave the same artifacts as well-known packers to evade defenses.

Antivirus/Antimalware

Employ heuristic-based malware detection. Ensure updated virus definitions and create custom signatures for observed malware.

Monitoring the following activities in your Organization can help you detect this technique.

File: File Metadata

Contextual data about a file, which may include information such as name, the content (ex: signature, headers, or data/media), user/ower, permissions, etc.

Use file scanning to look for known software packers or artifacts of packing techniques. Packing is not a definitive indicator of malicious activity, because legitimate software may use packing techniques to reduce binary size or to protect proprietary code.

Adversaries may match or approximate the name or location of legitimate files or resources when naming/placing them. This is done for the sake of evading defenses and observation. This may be done by placing an executable in a commonly trusted directory (ex: under System32) or giving it the name of a legitimate, trusted program (ex: svchost.exe). In containerized environments, this may also be done by creating a resource in a namespace that matches the naming convention of a container pod or cluster. Alternatively, a file or container image name given may be a close approximation to legitimate programs/images or something innocuous.

Adversaries may also use the same icon of the file they are trying to mimic.

Code Signing

Require signed binaries and images.

Execution Prevention

Use tools that restrict program execution via application control by attributes other than file name for common operating system utilities that are needed.

Restrict File and Directory Permissions

Use file system access controls to protect folders such as C:\Windows\System32.

Monitoring the following activities in your Organization can help you detect this technique.

File: File Metadata

Contextual data about a file, which may include information such as name, the content (ex: signature, headers, or data/media), user/ower, permissions, etc.

Collect file hashes; file names that do not match their expected hash are suspect. Perform file monitoring; files with known names but in unusual locations are suspect. Likewise, files that are modified outside of an update or patch are suspect.

Image: Image Metadata

Contextual data about a virtual machine image such as name, resource group, state, or type

In containerized environments, use image IDs and layer hashes to compare images instead of relying only on their names. Monitor for the unexpected creation of new resources within your cluster in Kubernetes, especially those created by atypical users.

Process: Process Metadata

Contextual data about a running process, which may include information such as environment variables, image name, user/owner, etc.

Collecting and comparing disk and resource filenames for binaries by looking to see if the InternalName, OriginalFilename, and/or ProductName match what is expected could provide useful leads, but may not always be indicative of malicious activity.

Adversaries may modify access tokens to operate under a different user or system security context to perform actions and bypass access controls. Windows uses access tokens to determine the ownership of a running process. A user can manipulate access tokens to make a running process appear as though it is the child of a different process or belongs to someone other than the user that started the process. When this occurs, the process also takes on the security context associated with the new token.

An adversary can use built-in Windows API functions to copy access tokens from existing processes; this is known as token stealing. These token can then be applied to an existing process (i.e. Token Impersonation/Theft) or used to spawn a new process (i.e. Create Process with Token). An adversary must already be in a privileged user context (i.e. administrator) to steal a token. However, adversaries commonly use token stealing to elevate their security context from the administrator level to the SYSTEM level. An adversary can then use a token to authenticate to a remote system as the account for that token if the account has appropriate permissions on the remote system.

Any standard user can use the runas command, and the Windows API functions, to create impersonation tokens; it does not require access to an administrator account. There are also other mechanisms, such as Active Directory fields, that can be used to modify access tokens.

Privileged Account Management

Limit permissions so that users and user groups cannot create tokens. This setting should be defined for the local system account only. GPO: Computer Configuration > [Policies] > Windows Settings > Security Settings > Local Policies > User Rights Assignment: Create a token object.  Also define who can create a process level token to only the local and network service through GPO: Computer Configuration > [Policies] > Windows Settings > Security Settings > Local Policies > User Rights Assignment: Replace a process level token.

Administrators should log in as a standard user but run their tools with administrator privileges using the built-in access token manipulation command runas.

User Account Management

An adversary must already have administrator level access on the local system to make full use of this technique; be sure to restrict users and accounts to the least privileges they require.

Monitoring the following activities in your Organization can help you detect this technique.

Active Directory: Active Directory Object Modification

Changes made to an active directory object (ex: Windows EID 5163 or 5136)

Monitor for changes made to AD settings that may modify access tokens to operate under a different user or system security context to perform actions and bypass access controls.

Command: Command Execution

Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)

Monitor executed commands and arguments for token manipulation by auditing command-line activity. Specifically, analysts should look for use of the runas command. Detailed command-line logging is not enabled by default in Windows.

Process: OS API Execution

Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)

Monitor for API calls, loaded by a payload, for token manipulation only through careful analysis of user network activity, examination of running processes, and correlation with other endpoint and network behavior. There are many Windows API calls a payload can take advantage of to manipulate access tokens (e.g., LogonUser, DuplicateTokenEx, and ImpersonateLoggedOnUser). Please see the referenced Windows API pages for more information.

Process: Process Creation

Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)

Monitor for executed processes that may modify access tokens to operate under a different user or system security context to perform actions and bypass access controls.

Process: Process Metadata

Contextual data about a running process, which may include information such as environment variables, image name, user/owner, etc.

Query systems for process and thread token information and look for inconsistencies such as user owns processes impersonating the local SYSTEM account. Look for inconsistencies between the various fields that store PPID information, such as the EventHeader ProcessId from data collected via Event Tracing for Windows (ETW), Creator Process ID/Name from Windows event logs, and the ProcessID and ParentProcessID (which are also produced from ETW and other utilities such as Task Manager and Process Explorer). The ETW provided EventHeader ProcessId identifies the actual parent process.

User Account: User Account Metadata

Contextual data about an account, which may include a username, user ID, environmental data, etc.

Monitor for contextual data about an account, which may include a username, user ID, environmental data, etc. that may modify access tokens to operate under a different user or system security context to perform actions and bypass access controls.

Adversaries may abuse Regsvr32.exe to proxy execution of malicious code. Regsvr32.exe is a command-line program used to register and unregister object linking and embedding controls, including dynamic link libraries (DLLs), on Windows systems. The Regsvr32.exe binary may also be signed by Microsoft. 

Malicious usage of Regsvr32.exe may avoid triggering security tools that may not monitor execution of, and modules loaded by, the regsvr32.exe process because of allowlists or false positives from Windows using regsvr32.exe for normal operations. Regsvr32.exe can also be used to specifically bypass application control using functionality to load COM scriptlets to execute DLLs under user permissions. Since Regsvr32.exe is network and proxy aware, the scripts can be loaded by passing a uniform resource locator (URL) to file on an external Web server as an argument during invocation. This method makes no changes to the Registry as the COM object is not actually registered, only executed.  This variation of the technique is often referred to as a "Squiblydoo" and has been used in campaigns targeting governments. 

Regsvr32.exe can also be leveraged to register a COM Object used to establish persistence via Component Object Model Hijacking.

Exploit Protection

Microsoft's Enhanced Mitigation Experience Toolkit (EMET) Attack Surface Reduction (ASR) feature can be used to block regsvr32.exe from being used to bypass application control.  Identify and block potentially malicious software executed through regsvr32 functionality by using application control  tools, like Windows Defender Application Control, AppLocker,  or Software Restriction Policies  where appropriate.

Monitoring the following activities in your Organization can help you detect this technique.

Command: Command Execution

Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)

Command arguments used before and after the regsvr32.exe invocation may also be useful in determining the origin and purpose of the script or DLL being loaded.

Module: Module Load

Attaching a module into the memory of a process/program, typically to access shared resources/features provided by the module (ex: Sysmon EID 7)

Monitor DLL/PE file events, specifically creation of these binary files as well as the loading of DLLs into processes. Look for DLLs that are not recognized or not normally loaded into a process.

Network Traffic: Network Connection Creation

Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)

Monitor for newly constructed network connections that are sent or received by untrusted hosts.

Process: Process Creation

Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)

Use process monitoring to monitor the execution and arguments of regsvr32.exe. Compare recent invocations of regsvr32.exe with prior history of known good arguments and loaded files to determine anomalous and potentially adversarial activity.

Adversaries may look for details about the network configuration and settings, such as IP and/or MAC addresses, of systems they access or through information discovery of remote systems. Several operating system administration utilities exist that can be used to gather this information. Examples include Arp, ipconfig/ifconfig, nbtstat, and route.

Adversaries may also leverage a Network Device CLI on network devices to gather information about configurations and settings, such as IP addresses of configured interfaces and static/dynamic routes.

Adversaries may use the information from System Network Configuration Discovery during automated discovery to shape follow-on behaviors, including determining certain access within the target network and what actions to do next.

This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.

Monitoring the following activities in your Organization can help you detect this technique.

Command: Command Execution

Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)

Monitor executed commands and arguments that may look for details about the network configuration and settings, such as IP and/or MAC addresses, of systems they access or through information discovery of remote systems.

Process: OS API Execution

Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)

Monitor for API calls (such as GetAdaptersInfo() and GetIpNetTable()) that may gather details about the network configuration and settings, such as IP and/or MAC addresses.

Process: Process Creation

Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)

Monitor for executed processes (such as ipconfig/ifconfig and arp) with arguments that may look for details about the network configuration and settings, such as IP and/or MAC addresses.

Script: Script Execution

Launching a list of commands through a script file (ex: Windows EID 4104)

Monitor for any attempts to enable scripts running on a system would be considered suspicious. If scripts are not commonly used on a system, but enabled, scripts running out of cycle from patching or other administrator functions are suspicious. Scripts should be captured from the file system when possible to determine their actions and intent.

An adversary may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture. Adversaries may use the information from System Information Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.

Tools such as Systeminfo can be used to gather detailed system information. If running with privileged access, a breakdown of system data can be gathered through the systemsetup configuration tool on macOS. As an example, adversaries with user-level access can execute the df -aH command to obtain currently mounted disks and associated freely available space. Adversaries may also leverage a Network Device CLI on network devices to gather detailed system information. System Information Discovery combined with information gathered from other forms of discovery and reconnaissance can drive payload development and concealment.

Infrastructure as a Service (IaaS) cloud providers such as AWS, GCP, and Azure allow access to instance and virtual machine information via APIs. Successful authenticated API calls can return data such as the operating system platform and status of a particular instance or the model view of a virtual machine.

This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.

Monitoring the following activities in your Organization can help you detect this technique.

Command: Command Execution

Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)

Monitor executed commands and arguments that may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture.

Process: OS API Execution

Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)

Monitor for API calls that may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture. 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 and PowerShell. In cloud-based systems, native logging can be used to identify access to certain APIs and dashboards that may contain system information. Depending on how the environment is used, that data alone may not be useful due to benign use during normal operations.

Process: Process Creation

Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)

Monitor newly executed processes that may attempt to get detailed information about the operating system and hardware, including version, patches, hotfixes, service packs, and architecture.

An adversary may gather the system time and/or time zone from a local or remote system. The system time is set and stored by the Windows Time Service within a domain to maintain time synchronization between systems and services in an enterprise network. 

System time information may be gathered in a number of ways, such as with Net on Windows by performing net time \hostname to gather the system time on a remote system. The victim's time zone may also be inferred from the current system time or gathered by using w32tm /tz. 

This information could be useful for performing other techniques, such as executing a file with a Scheduled Task/Job, or to discover locality information based on time zone to assist in victim targeting (i.e. System Location Discovery). Adversaries may also use knowledge of system time as part of a time bomb, or delaying execution until a specified date/time.

This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.

Monitoring the following activities in your Organization can help you detect this technique.

Command: Command Execution

Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)

Monitor executed commands and arguments for actions that may gather the system time and/or time zone from a local or remote system.

Process: OS API Execution

Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)

Monitor for API calls that may gather the system time and/or time zone from a local or remote system. Remote access tools with built-in features may interact directly with the Windows API to gather information.

Process: Process Creation

Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)

Monitor for newly executed processes that may gather the system time and/or time zone from a local or remote system.

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 may be used to gather information.

Some adversaries may also use Automated Collection on removable media.

Data Loss Prevention

Data loss prevention can restrict access to sensitive data and detect sensitive data that is unencrypted.

Monitoring the following activities in your Organization can help you detect this technique.

Command: Command Execution

Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)

Monitor executed commands and arguments for actions that could be taken to collect files from a system's connected removable media. For example, data may be acquired through Windows system management tools such as Windows Management Instrumentation and PowerShell.

File: File Access

Opening a file, which makes the file contents available to the requestor (ex: Windows EID 4663)

Monitor for unexpected/abnormal file accesses to removable media (optical disk drive, USB memory, etc.) connected to the compromised system.

Adversaries may stage collected data in a central location or directory on the local system prior to Exfiltration. Data may be kept in separate files or combined into one file through techniques such as Archive Collected Data. Interactive command shells may be used, and common functionality within cmd and bash may be used to copy data into a staging location.

Adversaries may also stage collected data in various available formats/locations of a system, including local storage databases/repositories or the Windows Registry.

This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.

Monitoring the following activities in your Organization can help you detect this technique.

Command: Command Execution

Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)

Monitor executed commands and arguments arguments for actions that could be taken to collect and combine files. Remote access tools with built-in features may interact directly with the Windows API to gather and copy to a location. Data may also be acquired and staged through Windows system management tools such as Windows Management Instrumentation and PowerShell.

File: File Access

Opening a file, which makes the file contents available to the requestor (ex: Windows EID 4663)

Monitor processes that appear to be reading files from disparate locations and writing them to the same directory or file may be an indication of data being staged, especially if they are suspected of performing encryption or compression on the files, such as 7zip, RAR, ZIP, or zlib.

File: File Creation

Initial construction of a new file (ex: Sysmon EID 11)

Monitor publicly writeable directories, central locations, and commonly used staging directories (recycle bin, temp folders, etc.) to regularly check for compressed or encrypted data that may be indicative of staging.

Windows Registry: Windows Registry Key Modification

Changes made to a Registry Key and/or Key value (ex: Windows EID 4657 or Sysmon EID 13|14)

Consider monitoring accesses and modifications to local storage repositories (such as the Windows Registry), especially from suspicious processes that could be related to malicious data collection.

Once established within a system or network, an adversary may use automated techniques for collecting internal data. Methods for performing this technique could include use of a Command and Scripting Interpreter to search for and copy information fitting set criteria such as file type, location, or name at specific time intervals. In cloud-based environments, adversaries may also use cloud APIs, command line interfaces, or extract, transform, and load (ETL) services to automatically collect data. This functionality could also be built into remote access tools.

This technique may incorporate use of other techniques such as File and Directory Discovery and Lateral Tool Transfer to identify and move files, as well as Cloud Service Dashboard and Cloud Storage Object Discovery to identify resources in cloud environments.

Encrypt Sensitive Information

Encryption and off-system storage of sensitive information may be one way to mitigate collection of files, but may not stop an adversary from acquiring the information if an intrusion persists over a long period of time and the adversary is able to discover and access the data through other means. Strong passwords should be used on certain encrypted documents that use them to prevent offline cracking through Brute Force techniques.

Remote Data Storage

Encryption and off-system storage of sensitive information may be one way to mitigate collection of files, but may not stop an adversary from acquiring the information if an intrusion persists over a long period of time and the adversary is able to discover and access the data through other means.

Monitoring the following activities in your Organization can help you detect this technique.

Command: Command Execution

Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)

Monitor executed commands and arguments for actions that could be taken to collect internal data.

File: File Access

Opening a file, which makes the file contents available to the requestor (ex: Windows EID 4663)

Monitor for unexpected files (i.e. .pdf, .docx, .jpg, etc.) viewed for collecting internal data.

Script: Script Execution

Launching a list of commands through a script file (ex: Windows EID 4104)

Monitor for any attempts to enable scripts running on a system would be considered suspicious. If scripts are not commonly used on a system, but enabled, scripts running out of cycle from patching or other administrator functions are suspicious. Scripts should be captured from the file system when possible to determine their actions and intent.

Adversaries may use utilities to compress and/or encrypt collected data prior to exfiltration. Many utilities include functionalities to compress, encrypt, or otherwise package data into a format that is easier/more secure to transport.

Adversaries may abuse various utilities to compress or encrypt data before exfiltration. Some third party utilities may be preinstalled, such as tar on Linux and macOS or zip on Windows systems. On Windows, diantz or makecab may be used to package collected files into a cabinet (.cab) file. diantz may also be used to download and compress files from remote locations (i.e. Remote Data Staging). Additionally, xcopy on Windows can copy files and directories with a variety of options.

Adversaries may use also third party utilities, such as 7-Zip, WinRAR, and WinZip, to perform similar activities.

Audit

System scans can be performed to identify unauthorized archival utilities.

Monitoring the following activities in your Organization can help you detect this technique.

Command: Command Execution

Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)

Monitor executed commands and arguments for actions that will aid in compression or encrypting data that is collected prior to exfiltration, such as tar.

File: File Creation

Initial construction of a new file (ex: Sysmon EID 11)

Monitor newly constructed files being written with extensions and/or headers associated with compressed or encrypted file types. Detection efforts may focus on follow-on exfiltration activity, where compressed or encrypted files can be detected in transit with a network intrusion detection or data loss prevention system analyzing file headers.

Process: Process Creation

Birth of a new running process (ex: Sysmon EID 1 or Windows EID 4688)

Monitor for newly constructed processes and/or command-lines that aid in compression or encrypting data that is collected prior to exfiltration, such as 7-Zip, WinRAR, and WinZip.

Adversaries may communicate using application layer protocols associated with web traffic to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.

Protocols such as HTTP and HTTPS that carry web traffic may be very common in environments. HTTP/S packets have many fields and headers in which data can be concealed. An adversary may abuse these protocols to communicate with systems under their control within a victim network while also mimicking normal, expected traffic.

Network Intrusion Prevention

Network intrusion detection and prevention systems that use network signatures to identify traffic for specific adversary malware can be used to mitigate activity at the network level.

Monitoring the following activities in your Organization can help you detect this technique.

Network Traffic: Network Traffic Content

Logged network traffic data showing both protocol header and body values (ex: PCAP)

Monitor and analyze traffic patterns and packet inspection associated to protocol(s), leveraging SSL/TLS inspection for encrypted traffic, that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).

Network Traffic: Network Traffic Flow

Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)

Monitor for web traffic to/from known-bad or suspicious domains and analyze traffic flows that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, or gratuitous or anomalous traffic patterns). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).

Adversaries may steal data by exfiltrating it over an existing command and control channel. Stolen data is encoded into the normal communications channel using the same protocol as command and control communications.

Data Loss Prevention

Data loss prevention can detect and block sensitive data being sent over unencrypted protocols.

Network Intrusion Prevention

Network intrusion detection and prevention systems that use network signatures to identify traffic for specific adversary malware can be used to mitigate activity at the network level. Signatures are often for unique indicators within protocols and may be based on the specific obfuscation technique used by a particular adversary or tool, and will likely be different across various malware families and versions. Adversaries will likely change tool command and control signatures over time or construct protocols in such a way to avoid detection by common defensive tools.

Monitoring the following activities in your Organization can help you detect this technique.

Command: Command Execution

Invoking a computer program directive to perform a specific task (ex: Windows EID 4688 of cmd.exe showing command-line parameters, ~/.bash_history, or ~/.zsh_history)

Monitor executed commands and arguments that may steal data by exfiltrating it over an existing command and control channel.

File: File Access

Opening a file, which makes the file contents available to the requestor (ex: Windows EID 4663)

Monitor for suspicious files (i.e. .pdf, .docx, .jpg, etc.) viewed in isolation that may steal data by exfiltrating it over an existing command and control channel.

Network Traffic: Network Connection Creation

Initial construction of a WMI object, such as a filter, consumer, subscription, binding, or provider (ex: Sysmon EIDs 19-21)

Monitor for newly constructed network connections that are sent or received by untrusted hosts.

Network Traffic: Network Traffic Content

Logged network traffic data showing both protocol header and body values (ex: PCAP)

Monitor and analyze traffic patterns and packet inspection associated to protocol(s) that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, gratuitous or anomalous traffic patterns, anomalous syntax, or structure). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments associated to traffic patterns (e.g. monitor anomalies in use of files that do not normally initiate connections for respective protocol(s)).

Network Traffic: Network Traffic Flow

Summarized network packet data, with metrics, such as protocol headers and volume (ex: Netflow or Zeek http.log)

Monitor network data for uncommon data flows. Processes utilizing the network that do not normally have network communication or have never been seen before are suspicious.