SigmaHQ/rules/windows/image_load/sysmon_in_memory_powershell.yml

title: In-memory PowerShell
id: 092bc4b9-3d1d-43b4-a6b4-8c8acd83522f
status: experimental
description: Detects loading of essential DLL used by PowerShell, but not by the process powershell.exe. Detects meterpreter's "load powershell" extension.
author: Tom Kern, oscd.community, Natalia Shornikova
date: 2019/11/14
modified: 2020/10/12
references:
    - https://adsecurity.org/?p=2921
    - https://github.com/p3nt4/PowerShdll
tags:
    - attack.t1086          # an old one
    - attack.t1059.001
    - attack.execution
logsource:
    category: image_load
    product: windows
detection:
    selection:
        ImageLoaded|endswith:
            - '\System.Management.Automation.Dll'
            - '\System.Management.Automation.ni.Dll'
    filter:
        Image|endswith:
            - '\powershell.exe'
            - '\powershell_ise.exe'
            - '\WINDOWS\System32\sdiagnhost.exe'
            - '\mscorsvw.exe'  # c:\Windows\Microsoft.NET\Framework64\v4.0.30319\mscorsw.exe for instance
            - '\WINDOWS\System32\RemoteFXvGPUDisablement.exe'  # on win10
            - '\sqlps.exe'
            - '\wsmprovhost.exe'
            - '\winrshost.exe'
            - '\syncappvpublishingserver.exe'
            - '\runscripthelper.exe'
            - '\ServerManager.exe'
       # User: 'NT AUTHORITY\SYSTEM'   # if set, matches all powershell processes not launched by SYSTEM
    condition: selection and not filter
falsepositives:
    - Used by some .NET binaries, minimal on user workstation.
level: high
enrichment:
    - EN_0001_cache_sysmon_event_id_1_info                      # http://bit.ly/314zc6x
    - EN_0003_enrich_other_sysmon_events_with_event_id_1_data   # http://bit.ly/2ojW7fw