Sigma rule: PowerShell Module File Created By Non-PowerShell Process

Rule

Title

PowerShell Module File Created By Non-PowerShell Process

Status

test

Level

medium

Author

Nasreddine Bencherchali (Nextron Systems)

Date

2023-05-09

Modified

2025-10-07

File

rules/windows/file/file_event/file_event_win_powershell_module_uncommon_creation.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the creation of a new PowerShell module ".psm1", ".psd1", ".dll", ".ps1", etc. by a non-PowerShell process

Log source

product

windows

category

file_event

Detection

selection:
    TargetFilename|contains:
        - '\WindowsPowerShell\Modules\'
        - '\PowerShell\7\Modules\'
filter_main_pwsh:
    Image|endswith:
        - ':\Program Files\PowerShell\7-preview\pwsh.exe'
        - ':\Program Files\PowerShell\7\pwsh.exe'
        - ':\Windows\System32\poqexec.exe' # https://github.com/SigmaHQ/sigma/issues/4448
        - ':\Windows\System32\WindowsPowerShell\v1.0\powershell_ise.exe'
        - ':\Windows\System32\WindowsPowerShell\v1.0\powershell.exe'
        - ':\Windows\SysWOW64\poqexec.exe' # https://github.com/SigmaHQ/sigma/issues/4448
        - ':\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell_ise.exe'
        - ':\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe'
filter_main_msiexec:
    Image:
        - 'C:\Windows\System32\msiexec.exe'
        - 'C:\Windows\SysWOW64\msiexec.exe'
condition: selection and not 1 of filter_main_*

False positives (as the rule lists them)

• Unknown

Tags

• attack.persistence

References

• Internal Research
• https://learn.microsoft.com/en-us/powershell/scripting/developer/module/understanding-a-windows-powershell-module?view=powershell-7.3

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/file/file_event/file_event_win_powershell_module_uncommon_creation.yml