Detectionmediumexperimental

Potentially Suspicious WDAC Policy File Creation

Detects suspicious Windows Defender Application Control (WDAC) policy file creation from abnormal processes that could be abused by attacker to block EDR/AV components while allowing their own malicious code to run on the system.

Convert In Phoenix Studio

Open this Sigma rule in the converter with the YAML preloaded and ready for backend selection.

Launch

X__JuniorCreated Fri Feb 07Updated Wed Dec 031d2de8a6-4803-4fde-b85b-f58f3aa7a705windows

Log Source

WindowsFile Event

ProductWindows← raw: windows

CategoryFile Event← raw: file_event

Events for file system activity including creation, modification, and deletion.

Detection Logic

detection:
    selection_target:
        # This is a default location but unfortunately it could be any path configured in Group Policy Management Editor.
        # No file extension needed because any extension would work, check first reference.
        TargetFilename|contains: '\Windows\System32\CodeIntegrity\'
    filter_main_images:
        Image|endswith:
            - '\Microsoft.ConfigurationManagement.exe' # Replace with full path to avoid false negatives
            - '\WDAC Wizard.exe' # Replace with full path to avoid false negatives
            - 'C:\Program Files\PowerShell\7-preview\pwsh.exe'
            - 'C:\Program Files\PowerShell\7\pwsh.exe'
            - 'C:\Windows\System32\dllhost.exe'
            - 'C:\Windows\System32\WindowsPowerShell\v1.0\powershell_ise.exe'
            - 'C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe'
            - 'C:\Windows\SysWOW64\dllhost.exe'
            - 'C:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell_ise.exe'
            - 'C:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe'
    filter_main_cli:
        - CommandLine|contains|all:
              - 'ConvertFrom-CIPolicy -XmlFilePath'
              - '-BinaryFilePath '
        - CommandLine|contains: 'CiTool --update-policy'
        - CommandLine|contains|all:
              - 'Copy-Item -Path'
              - '-Destination'
    filter_main_system:
        Image: 'System'
    filter_main_wuauclt:
        Image:
            - 'C:\Windows\System32\wuauclt.exe'
            - 'C:\Windows\UUS\arm64\wuaucltcore.exe'
    condition: selection_target and not 1 of filter_main_*