Meterpreter or Cobalt Strike Getsystem Service Installation - System — Sigma Rule

Rule metadata and linked tags

Author: Teymur Kheirkhabarov, Ecco, Florian Roth (Nextron Systems). Source status: test; severity: high. Source dates: 2019-10-26 / 2023-11-15.

{
  "product": "windows",
  "service": "system"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 79a95984f14c2d95cc3770ed069894de8fa5299d605be817a980a5f939721f58

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: Meterpreter or Cobalt Strike Getsystem Service Installation - System
id: 843544a7-56e0-4dcc-a44f-5cc266dd97d6
status: test
description: Detects the use of getsystem Meterpreter/Cobalt Strike command by detecting a specific service installation
references:
    - https://speakerdeck.com/heirhabarov/hunting-for-privilege-escalation-in-windows-environment
    - https://blog.cobaltstrike.com/2014/04/02/what-happens-when-i-type-getsystem/
author: Teymur Kheirkhabarov, Ecco, Florian Roth (Nextron Systems)
date: 2019-10-26
modified: 2023-11-15
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1134.001
    - attack.t1134.002
logsource:
    product: windows
    service: system
detection:
    selection_id:
        Provider_Name: 'Service Control Manager'
        EventID: 7045
    selection_cli_cmd:
        # meterpreter getsystem technique 1: cmd.exe /c echo 559891bb017 > \\.\pipe\5e120a
        # cobaltstrike getsystem technique 1: %COMSPEC% /c echo 559891bb017 > \\.\pipe\5e120a
        # cobaltstrike getsystem technique 1b (expanded %COMSPEC%): %COMSPEC% /c echo 559891bb017 > \\.\pipe\5e120a
        ImagePath|contains|all:
            - '/c'
            - 'echo'
            - '\pipe\'
        ImagePath|contains:
        - 'cmd'
        - '%COMSPEC%'
    selection_cli_rundll:
        # meterpreter getsystem technique 2: rundll32.exe C:\Users\test\AppData\Local\Temp\tmexsn.dll,a /p:tmexsn
        ImagePath|contains|all:
            - 'rundll32'
            - '.dll,a'
            - '/p:'
    selection_cli_share:
        ImagePath|startswith: '\\\\127.0.0.1\\ADMIN$\'  # https://twitter.com/svch0st/status/1413688851877416960?lang=en
    condition: selection_id and 1 of selection_cli_*
falsepositives:
    - Unlikely
level: high

Original YAML and metadata in JSON

False positives

• Unlikely

Source references

• https://speakerdeck.com/heirhabarov/hunting-for-privilege-escalation-in-windows-environment
• https://blog.cobaltstrike.com/2014/04/02/what-happens-when-i-type-getsystem/