Elevated System Shell Spawned From Uncommon Parent Location — Sigma Rule

Rule metadata and linked tags

Author: frack113, Tim Shelton (update fp). Source status: test; severity: medium. Source dates: 2022-12-05 / 2025-03-06.

{
  "product": "windows",
  "category": "process_creation"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 6fc1a68a59218ff8711cf09579e9a02bb2ed69abe27314cc4941be07cda152ec

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: Elevated System Shell Spawned From Uncommon Parent Location
id: 178e615d-e666-498b-9630-9ed363038101
related:
    - id: 61065c72-5d7d-44ef-bf41-6a36684b545f
      type: similar
status: test
description: Detects when a shell program such as the Windows command prompt or PowerShell is launched with system privileges from a uncommon parent location.
references:
    - https://github.com/Wh04m1001/SysmonEoP
author: frack113, Tim Shelton (update fp)
date: 2022-12-05
modified: 2025-03-06
tags:
    - attack.privilege-escalation
    - attack.execution
    - attack.t1059
logsource:
    product: windows
    category: process_creation
detection:
    selection_shell:
        - Image|endswith:
              - '\powershell.exe'
              - '\powershell_ise.exe'
              - '\pwsh.exe'
              - '\cmd.exe'
        - OriginalFileName:
              - 'PowerShell.EXE'
              - 'powershell_ise.EXE'
              - 'pwsh.dll'
              - 'Cmd.Exe'
    selection_user:
        User|contains: # covers many language settings
            - 'AUTHORI'
            - 'AUTORI'
        LogonId: '0x3e7'
    filter_main_generic:
        # Example 1:
        #   C:\Program Files\erl-23.2\erts-11.1.4\bin\erl.exe" -service_event ErlSrv_RabbitMQ -nohup -sname rabbit@localhost -s rabbit boot -boot start_sasl +W w +MBas ageffcbf +MHas ageffcbf +MBlmbcs 512 +MHlmbcs 512 +MMmcs 30 +P 1048576 +t 5000000 +stbt db +zdbbl 128000 +sbwt none +sbwtdcpu none +sbwtdio none -kernel inet_dist_listen_min 25672 -kernel inet_dist_listen_max 25672 -lager crash_log false -lager handlers []
        # Example 2:
        #   ParentImage: C:\Program Files (x86)\Varonis\DatAdvantage\GridCollector\VrnsRealTimeAlertsSvc.exe" /appid 000000ad-cb03-500b-9459-c46d000000ad
        #   CommandLine: C:\Windows\system32\cmd.exe /c C:\Program Files "(x86)\Varonis\DatAdvantage\GridCollector\handle_scopes.cmd C:\Collector" Working Share\VaronisWorkDirectoryCollector
        ParentImage|contains:
            - ':\Program Files (x86)\'
            - ':\Program Files\'
            - ':\ProgramData\'
            - ':\Windows\System32\'
            - ':\Windows\SysWOW64\'
            - ':\Windows\Temp\' # Installers
            - ':\Windows\WinSxS\'
    filter_optional_manageengine:
        # Example:
        #   ParentImage: C:/ManageEngine/ADManager Plus/pgsql/bin/postgres.exe" --forkarch 5380
        #   CommandLine: C:\Windows\system32\cmd.exe /c "IF EXIST archive.bat (archive.bat pg_wal\000000010000008E000000EA 000000010000008E000000EA)
        ParentImage|endswith: ':\ManageEngine\ADManager Plus\pgsql\bin\postgres.exe'
        Image|endswith: '\cmd.exe'
    filter_optional_asgard:
        CommandLine|contains: ':\WINDOWS\system32\cmd.exe /c "'
        CurrentDirectory|contains: ':\WINDOWS\Temp\asgard2-agent\'
    filter_optional_ibm_spectrumprotect:
        ParentImage|contains: ':\IBM\SpectrumProtect\webserver\scripts\'
        CommandLine|contains: ':\IBM\SpectrumProtect\webserver\scripts\'
    filter_main_parent_null:
        ParentImage: null
    filter_main_parent_empty:
        ParentImage:
            - ''
            - '-'
    condition: all of selection_* and not 1 of filter_main_* and not 1 of filter_optional_*
falsepositives:
    - Some legitimate applications may spawn shells from uncommon parent locations. Apply additional filters and perform an initial baseline before deploying.
level: medium

Original YAML and metadata in JSON

False positives

• Some legitimate applications may spawn shells from uncommon parent locations. Apply additional filters and perform an initial baseline before deploying.

Source references

• https://github.com/Wh04m1001/SysmonEoP