Suspicious PowerShell Module File Created By Non-PowerShell Process (via file_event)

title: Suspicious PowerShell Module File Created By Non-PowerShell Process (via file_event)
id: 5835eca5-13a6-5e05-9696-b8b8c1ead65e
status: stable
description: This rule 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: Huntrule Team
date: 2026-05-04
tags:
    - attack.persistence
    - attack.execution
    - attack.t1059.001
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'
            - ':\Windows\System32\WindowsPowerShell\v1.0\powershell_ise.exe'
            - ':\Windows\System32\WindowsPowerShell\v1.0\powershell.exe'
            - ':\Windows\SysWOW64\poqexec.exe'
            - ':\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