DMSA Service Account Created in Specific OUs - PowerShell — Sigma Rule

Rule metadata and linked tags

Author: Swachchhanda Shrawan Poudel (Nextron Systems). Source status: experimental; severity: medium. Source dates: 2025-05-24 / not supplied.

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: f539953d436b3ec6bdcc2682c17b3f7aaef22bd276c1aff9994f53820e69fe4f

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: DMSA Service Account Created in Specific OUs - PowerShell
id: 02122374-b74e-495c-b285-9e4da973f3d6
related:
    - id: e15bc294-ae2a-45ad-b7d6-637b33868bde # Windows Security Creation of New MsDS-DelegatedManagedServiceAccount (DMSA) Object
      type: similar
    - id: 0ea8db81-2ff6-4525-9448-33bbe7effc13 # Process Creation Detection
      type: similar
status: experimental
description: |
    Detects the creation of a dMSA service account using the New-ADServiceAccount cmdlet in certain OUs.
    The fact that the cmdlet is used to create a dMSASvc account in a specific OU is highly suspicious.
    It is a pattern trying to exploit the BadSuccessor privilege escalation vulnerability in Windows Server 2025.
    On top of that, if the user that is creating the dMSASvc account is not a legitimate administrator or does not have the necessary permissions,
    it is a strong signal of an attempted or successful abuse of the BaDSuccessor vulnerability for privilege escalation within the Windows Server 2025 Active Directory environment.
references:
    - https://www.akamai.com/blog/security-research/abusing-bad-successor-for-privilege-escalation-in-active-directory
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-05-24
tags:
    - attack.privilege-escalation
    - attack.initial-access
    - attack.persistence
    - attack.stealth
    - attack.t1078.002
    - attack.t1098
logsource:
    category: ps_script
    product: windows
detection:
    selection:
        ScriptBlockText|contains|all:
            - 'New-ADServiceAccount'
            - '-CreateDelegatedServiceAccount'
            - '-path'
    condition: selection
falsepositives:
    - Unknown
level: medium

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://www.akamai.com/blog/security-research/abusing-bad-successor-for-privilege-escalation-in-active-directory