Potential Meterpreter/CobaltStrike Activity — Sigma Rule

Rule metadata and linked tags

Author: Teymur Kheirkhabarov, Ecco, Florian Roth. Source status: test; severity: high. Source dates: 2019-10-26 / 2023-02-05.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 88fe73438af18fbe00d308b30f9fde8d9873b18f76ca5f259d599b2459d9ff71

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: Potential Meterpreter/CobaltStrike Activity
id: 15619216-e993-4721-b590-4c520615a67d
status: test
description: Detects the use of getsystem Meterpreter/Cobalt Strike command by detecting a specific service starting
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
date: 2019-10-26
modified: 2023-02-05
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1134.001
    - attack.t1134.002
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        ParentImage|endswith: '\services.exe'
    selection_technique_1:
        # Examples:
        #   Meterpreter  getsystem technique 1: cmd.exe /c echo 559891bb017 > \\.\pipe\5e120a
        #   CobaltStrike getsystem technique 1b (expanded env var): %COMSPEC% /c echo 559891bb017 > \\.\pipe\5e120a
        #   CobaltStrike getsystem technique 1: %COMSPEC% /c echo 559891bb017 > \\.\pipe\5e120a
        CommandLine|contains|all:
            - '/c'
            - 'echo'
            - '\pipe\'
        CommandLine|contains:
            - 'cmd'
            - '%COMSPEC%'
    selection_technique_2:
        # meterpreter getsystem technique 2: rundll32.exe C:\Users\test\AppData\Local\Temp\tmexsn.dll,a /p:tmexsn
        CommandLine|contains|all:
            - 'rundll32'
            - '.dll,a'
            - '/p:'
    filter_defender:
        CommandLine|contains: 'MpCmdRun'
    condition: selection_img and 1 of selection_technique_* and not 1 of filter_*
falsepositives:
    - Commandlines containing components like cmd accidentally
    - Jobs and services started with cmd
level: high

Original YAML and metadata in JSON

False positives

• Commandlines containing components like cmd accidentally
• Jobs and services started with cmd

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/