Suspicious Child Process Created as System — Sigma Rule

Rule metadata and linked tags

Author: Teymur Kheirkhabarov, Roberto Rodriguez (@Cyb3rWard0g), Open Threat Research (OTR). Source status: test; severity: high. Source dates: 2019-10-26 / 2024-12-01.

{
  "category": "process_creation",
  "product": "windows",
  "definition": "Requirements: ParentUser field needs sysmon >= 13.30"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 84bd6b7f0ba6bcfd994263de4f6fa1ea495766de788d1d779b167caa97521041

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: Suspicious Child Process Created as System
id: 590a5f4c-6c8c-4f10-8307-89afe9453a9d
status: test
description: Detection of child processes spawned with SYSTEM privileges by parents with LOCAL SERVICE or NETWORK SERVICE accounts
references:
    - https://speakerdeck.com/heirhabarov/hunting-for-privilege-escalation-in-windows-environment
    - https://foxglovesecurity.com/2016/09/26/rotten-potato-privilege-escalation-from-service-accounts-to-system/
    - https://github.com/antonioCoco/RogueWinRM
    - https://twitter.com/Cyb3rWard0g/status/1453123054243024897
author: Teymur Kheirkhabarov, Roberto Rodriguez (@Cyb3rWard0g), Open Threat Research (OTR)
date: 2019-10-26
modified: 2024-12-01
tags:
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1134.002
logsource:
    category: process_creation
    product: windows
    definition: 'Requirements: ParentUser field needs sysmon >= 13.30'
detection:
    selection:
        ParentUser|contains:
            - 'AUTHORI'
            - 'AUTORI'
        ParentUser|endswith:
            - '\NETWORK SERVICE'
            - '\LOCAL SERVICE'
        User|contains: # covers many language settings
            - 'AUTHORI'
            - 'AUTORI'
        User|endswith: # System
            - '\SYSTEM'
            - '\Système'
            - '\СИСТЕМА'
        IntegrityLevel:
            - 'System'
            - 'S-1-16-16384'
    filter_rundll32:
        Image|endswith: '\rundll32.exe'
        CommandLine|contains: 'DavSetCookie'
    condition: selection and not 1 of filter_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://speakerdeck.com/heirhabarov/hunting-for-privilege-escalation-in-windows-environment
• https://foxglovesecurity.com/2016/09/26/rotten-potato-privilege-escalation-from-service-accounts-to-system/
• https://github.com/antonioCoco/RogueWinRM
• https://twitter.com/Cyb3rWard0g/status/1453123054243024897