DMSA Link Attributes Modified — Sigma Rule

Rule metadata and linked tags

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

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

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: af566b45640475635b7a4c0e06b89eb3f6e424d53b41592c064c3a39ee7ab694

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 Link Attributes Modified
id: 9b111d8e-92e0-4153-88bc-daefc1333aba
related:
    - id: 6c9eb492-e477-4df9-b0f4-571fc9db29cd # Windows Security Modification of msDS-ManagedAccountPrecededByLink Attribute
      type: similar
status: experimental
description: |
    Detects modification of dMSA link attributes (msDS-ManagedAccountPrecededByLink) via PowerShell scripts.
    This command line pattern could be an indicator an attempt to exploit the BadSuccessor privilege escalation vulnerability in Windows Server 2025.
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.persistence
    - attack.initial-access
    - attack.stealth
    - attack.t1078.002
    - attack.t1098
logsource:
    category: ps_script
    product: windows
detection:
    selection:
        ScriptBlockText|contains|all:
            - '.Put("msDS-ManagedAccountPrecededByLink'
            - 'CN='
    condition: selection
falsepositives:
    - Legitimate administrative tasks modifying these attributes.
level: low

Original YAML and metadata in JSON

False positives

• Legitimate administrative tasks modifying these attributes.

Source references

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