PowerShell Module File Created By Non-PowerShell Process

title: PowerShell Module File Created By Non-PowerShell Process
id: e3845023-ca9a-4024-b2b2-5422156d5527
status: test
description: Detects the creation of a new PowerShell module ".psm1", ".psd1", ".dll", ".ps1", etc. by a non-PowerShell process
references:
    - Internal Research
    - https://learn.microsoft.com/en-us/powershell/scripting/developer/module/understanding-a-windows-powershell-module?view=powershell-7.3
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-05-09
modified: 2025-10-07
tags:
    - attack.persistence
logsource:
    category: file_event
    product: windows
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_*
falsepositives:
    - Unknown
level: medium