Potential Script Proxy Execution Via CL_Mutexverifiers.ps1

Detects the use of the Microsoft signed script "CL_mutexverifiers" to proxy the execution of additional PowerShell script commands

Sigma rule (View on GitHub)

 1title: Potential Script Proxy Execution Via CL_Mutexverifiers.ps1
 2id: 1e0e1a81-e79b-44bc-935b-ddb9c8006b3d
 3status: test
 4description: Detects the use of the Microsoft signed script "CL_mutexverifiers" to proxy the execution of additional PowerShell script commands
 5references:
 6    - https://lolbas-project.github.io/lolbas/Scripts/CL_mutexverifiers/
 7author: Nasreddine Bencherchali (Nextron Systems), oscd.community, Natalia Shornikova, frack113
 8date: 2022/05/21
 9modified: 2023/08/17
10tags:
11    - attack.defense_evasion
12    - attack.t1216
13logsource:
14    category: process_creation
15    product: windows
16detection:
17    selection_pwsh:
18        ParentImage|endswith:
19            # Note: to avoid potential FPs we assume the script was launched from powershell. But in theory it can be launched by any Powershell like process
20            - '\powershell.exe'
21            - '\pwsh.exe'
22        Image|endswith: '\powershell.exe'
23        CommandLine|contains: ' -nologo -windowstyle minimized -file '
24    selection_temp:
25        # Note: Since the function uses "env:temp" the value will change depending on the context of exec
26        CommandLine|contains:
27            - '\AppData\Local\Temp\'
28            - '\Windows\Temp\'
29    condition: all of selection_*
30falsepositives:
31    - Unknown
32level: medium

References

Related rules

to-top