Potentially Suspicious WDAC Policy File Creation

calendar Feb 17, 2025 · attack.defense-evasion  ·
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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.

Sigma rule (View on GitHub)

 1title: Potentially Suspicious WDAC Policy File Creation
 2id: 1d2de8a6-4803-4fde-b85b-f58f3aa7a705
 3status: experimental
 4description: |
 5        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.
 6references:
 7    - https://learn.microsoft.com/en-us/windows/security/application-security/application-control/app-control-for-business/deployment/deploy-appcontrol-policies-using-group-policy
 8    - https://beierle.win/2024-12-20-Weaponizing-WDAC-Killing-the-Dreams-of-EDR/
 9    - https://github.com/logangoins/Krueger/tree/main
10    - https://learn.microsoft.com/en-us/windows/security/application-security/application-control/app-control-for-business/deployment/appcontrol-deployment-guide
11    - https://learn.microsoft.com/en-us/windows/security/application-security/application-control/app-control-for-business/deployment/deploy-appcontrol-policies-with-script
12    - https://learn.microsoft.com/en-us/windows/security/application-security/application-control/app-control-for-business/deployment/deploy-appcontrol-policies-with-memcm
13author: X__Junior
14date: 2025-02-07
15tags:
16    - attack.defense-evasion
17logsource:
18    category: file_event
19    product: windows
20detection:
21    selection_target:
22        # This is a default location but unfortunately it could be any path configured in Group Policy Management Editor.
23        # No file extension needed because any extension would work, check first reference.
24        TargetFilename|contains: '\Windows\System32\CodeIntegrity\'
25    filter_main_images:
26        Image|endswith:
27            - '\Microsoft.ConfigurationManagement.exe' # Replace with full path to avoid false negatives
28            - '\WDAC Wizard.exe' # Replace with full path to avoid false negatives
29            - 'C:\Program Files\PowerShell\7-preview\pwsh.exe'
30            - 'C:\Program Files\PowerShell\7\pwsh.exe'
31            - 'C:\Windows\System32\dllhost.exe'
32            - 'C:\Windows\System32\WindowsPowerShell\v1.0\powershell_ise.exe'
33            - 'C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe'
34            - 'C:\Windows\SysWOW64\dllhost.exe'
35            - 'C:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell_ise.exe'
36            - 'C:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe'
37    filter_main_cli:
38        - CommandLine|contains|all:
39              - 'ConvertFrom-CIPolicy -XmlFilePath'
40              - '-BinaryFilePath '
41        - CommandLine|contains: 'CiTool --update-policy'
42        - CommandLine|contains|all:
43              - 'Copy-Item -Path'
44              - '-Destination'
45    condition: selection_target and not 1 of filter_main_*
46falsepositives:
47    - Administrators and security vendors could leverage WDAC, apply additional filters as needed.
48level: medium

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