New DMSA Service Account Created in Specific OUs

Title: New DMSA Service Account Created in Specific OUs
Status: experimental
Description:Detects the creation of a dMSASvc 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
modified:None
Tags:

• -'attack.privilege-escalation'
• -'attack.initial-access'
• -'attack.persistence'
• -'attack.stealth'
• -'attack.t1078.002'
• -'attack.t1098'

Logsource:

• category: process_creation
• product: windows

Detection:
  selection_img:
    - Image|endswith:
      - '\powershell.exe'
      - '\pwsh.exe'
      - '\powershell_ise.exe'
    - OriginalFileName:
      - 'powershell.exe'
      - 'pwsh.dll'
      - 'powershell_ise.exe'
  selection_cli:
    CommandLine|contains|all:
      -'New-ADServiceAccount'
      -'-CreateDelegatedServiceAccount'
      -'-path'

  condition:all of selection_*
Falsepositives:
  -Unknown
Level: medium