Sigma rule: msDS-ManagedAccountPrecededByLink Attribute Modified

Rule

Title

msDS-ManagedAccountPrecededByLink Attribute Modified

Status

experimental

Level

medium

Author

Swachchhanda Shrawan Poudel (Nextron Systems)

Date

2025-05-24

File

rules-placeholder/windows/builtin/security/win_security_modification_of_msds_dmsa_link_attribute.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects modifications to the msDS-ManagedAccountPrecededByLink attribute, which may indicate an attempted or successful abuse of the BaD-Successor msDS-DelegatedManagedServiceAccount (DMSA) vulnerability.
The DMSA is a new object class introduced in Windows Server 2025 that allows administrators to delegate the management of service accounts to other users or groups.
Changes to this attribute by suspicious accounts or outside of normal administrative workflows are a strong signal of an attempted or successful abuse.
If it is indeed modified by an account that is not typically responsible for such changes, it could indicate an attempt to exploit the BaD-Successor vulnerability for privilege escalation within the Windows Server 2025 Active Directory environment.

Log source

product

windows

service

security

definition

Requirements: Audit Policy : Account Management > Audit User Account Management, Group Policy : Computer Configuration\Windows Settings\Security Settings\Advanced Audit Policy Configuration\Audit Policies\Account Management\Audit User Account Management, DS Access > Audit Directory Service Changes, Group Policy : Computer Configuration\Windows Settings\Security Settings\Advanced Audit Policy Configuration\Audit Policies\DS Access\Audit Directory Service Changes

Detection

selection:
    EventID: 5136
    ObjectClass: 'msDS-DelegatedManagedServiceAccount'
    AttributeLDAPDisplayName: 'msDS-ManagedAccountPrecededByLink'
filter_main_legitimate_accounts:
    # Exclude modifications made by the system or legitimate administrative accounts
    - SubjectAccountName: 'SYSTEM'
    - SubjectAccountName|expand: '%Administrators%' # Add all members of the Administrators group to this placeholder
condition: selection and not 1 of filter_main_*

False positives (as the rule lists them)

• Unknown

Tags

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

MITRE ATT&CK ids this rule names

• T1078.002
• T1098

Related rules

• 9b111d8e-92e0-4153-88bc-daefc1333aba (similar)

References

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

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-placeholder/windows/builtin/security/win_security_modification_of_msds_dmsa_link_attribute.yml