WinAPI Function Calls Via PowerShell Scripts

title: WinAPI Function Calls Via PowerShell Scripts
id: 9f22ccd5-a435-453b-af96-bf99cbb594d4
related:
    - id: ba3f5c1b-6272-4119-9dbd-0bc8d21c2702
      type: similar
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      type: similar
    - id: 19d65a1c-8540-4140-8062-8eb00db0bba5
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status: test
description: Detects calls to WinAPI functions from PowerShell scripts. Attackers can often leverage these APIs to avoid detection based on typical PowerShell function calls. Use this rule as a basis to hunt for interesting scripts.
references:
    - https://speakerdeck.com/heirhabarov/hunting-for-powershell-abuse
author: Nikita Nazarov, oscd.community, Nasreddine Bencherchali (Nextron Systems)
date: 2023-07-21
tags:
    - attack.execution
    - attack.t1059.001
    - attack.t1106
    - detection.threat-hunting
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains:
            - 'AddSecurityPackage'
            - 'AdjustTokenPrivileges'
            - 'CloseHandle'
            - 'CreateProcessWithToken'
            - 'CreateRemoteThread'
            - 'CreateThread'
            - 'CreateUserThread'
            - 'DangerousGetHandle'
            - 'DuplicateTokenEx'
            - 'EnumerateSecurityPackages'
            - 'FreeLibrary'
            - 'GetDelegateForFunctionPointer'
            - 'GetLogonSessionData'
            - 'GetModuleHandle'
            - 'GetProcAddress'
            - 'GetProcessHandle'
            - 'GetTokenInformation'
            - 'ImpersonateLoggedOnUser'
            - 'LoadLibrary'
            - 'memcpy'
            - 'MiniDumpWriteDump'
            - 'OpenDesktop'
            - 'OpenProcess'
            - 'OpenProcessToken'
            - 'OpenThreadToken'
            - 'OpenWindowStation'
            - 'QueueUserApc'
            - 'ReadProcessMemory'
            - 'RevertToSelf'
            - 'RtlCreateUserThread'
            - 'SetThreadToken'
            - 'VirtualAlloc'
            - 'VirtualFree'
            - 'VirtualProtect'
            - 'WaitForSingleObject'
            - 'WriteInt32'
            - 'WriteProcessMemory'
            - 'ZeroFreeGlobalAllocUnicode'
    condition: selection
falsepositives:
    - This rule is mainly used for hunting and will generate quite a lot of false positives when applied in production. It's best combined with other fields such as the path of execution, the parent process, etc.
level: medium