Creation of Possible Suspicious PowerShell Module File (via file_event)

title: Creation of Possible Suspicious PowerShell Module File (via file_event)
id: 0ed65b33-90c6-50f0-9a16-0a150599258d
status: stable
description: This rule detects the creation of a new PowerShell module in the first folder of the module directory structure "\WindowsPowerShell\Modules\malware\malware.psm1". This is somewhat an uncommon practice as legitimate modules frequently includes a version folder.
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: 2026-03-19
tags:
    - attack.persistence
    - attack.t1059.001
logsource:
    category: file_event
    product: windows
detection:
    selection:
        TargetFilename|endswith:
            - '\\WindowsPowerShell\\Modules\\*\.ps'
            - '\\WindowsPowerShell\\Modules\\*\.dll'
    condition: selection
falsepositives:
    - Unknown
level: medium