User Added to Local Administrator Group — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems). Source status: stable; severity: medium. Source dates: 2017-03-14 / 2021-01-17.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: dd8c29a1518185705daaee566abe921e1ffbe2d5801a3549a52dd59bfefb2885

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: User Added to Local Administrator Group
id: c265cf08-3f99-46c1-8d59-328247057d57
status: stable
description: Detects the addition of a new member to the local administrator group, which could be legitimate activity or a sign of privilege escalation activity
references:
    - https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/auditing/event-4732
    - https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/manage/understand-security-identifiers
author: Florian Roth (Nextron Systems)
date: 2017-03-14
modified: 2021-01-17
tags:
    - attack.initial-access
    - attack.privilege-escalation
    - attack.stealth
    - attack.t1078
    - attack.persistence
    - attack.t1098
logsource:
    product: windows
    service: security
detection:
    selection_eid:
        EventID: 4732
    selection_group:
        - TargetUserName|startswith: 'Administr'
        - TargetSid: 'S-1-5-32-544'
    filter_main_computer_accounts:
        SubjectUserName|endswith: '$'
    condition: all of selection_* and not 1 of filter_*
falsepositives:
    - Legitimate administrative activity
level: medium

Original YAML and metadata in JSON

False positives

• Legitimate administrative activity

Source references

• https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/auditing/event-4732
• https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/manage/understand-security-identifiers