Service DACL Abuse To Hide Services Via Sc.EXE — Sigma Rule

Rule metadata and linked tags

Author: Andreas Hunkeler (@Karneades). Source status: test; severity: high. Source dates: 2021-12-20 / 2022-08-08.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 748f440ffb11ec6e08ce795cd1135cd252444bbed24c682b6ffc956b1b8e5d09

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: Service DACL Abuse To Hide Services Via Sc.EXE
id: a537cfc3-4297-4789-92b5-345bfd845ad0
related:
    - id: 99cf1e02-00fb-4c0d-8375-563f978dfd37 # Deny Service Access
      type: similar
    - id: 98c5aeef-32d5-492f-b174-64a691896d25 # Generic SD tampering
      type: similar
status: test
description: Detects usage of the "sc.exe" utility adding a new service with special permission seen used by threat actors which makes the service hidden and unremovable.
references:
    - https://blog.talosintelligence.com/2021/10/threat-hunting-in-large-datasets-by.html
    - https://www.sans.org/blog/red-team-tactics-hiding-windows-services/
    - https://twitter.com/Alh4zr3d/status/1580925761996828672
    - https://itconnect.uw.edu/tools-services-support/it-systems-infrastructure/msinf/other-help/understanding-sddl-syntax/
author: Andreas Hunkeler (@Karneades)
date: 2021-12-20
modified: 2022-08-08
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.execution
    - attack.stealth
    - attack.t1574.011
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\sc.exe'
        - OriginalFileName: 'sc.exe'
    selection_cli:
        CommandLine|contains|all:
            - 'sdset'
            # Summary of permissions
            #   DC: Delete All Child Objects
            #   LC: List Contents
            #   WP: Write All Properties
            #   DT: Delete Subtree
            #   SD: Delete
            - 'DCLCWPDTSD'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://blog.talosintelligence.com/2021/10/threat-hunting-in-large-datasets-by.html
• https://www.sans.org/blog/red-team-tactics-hiding-windows-services/
• https://twitter.com/Alh4zr3d/status/1580925761996828672
• https://itconnect.uw.edu/tools-services-support/it-systems-infrastructure/msinf/other-help/understanding-sddl-syntax/