AD-COMP-05: Computer SID History count should be retrievable
| ID | AD-COMP-05 |
| Severity | Info |
| Suite | Active Directory (on-premises) |
| Product | Active Directory |
| Feature | Computers |
| Security area | Identity lifecycle and hygiene |
| Resource type | Computer |
| MITRE ATT&CK | T1134.005 |
| Reads from | On-premises Active Directory |
What this checks and how to fix it
Section titled “What this checks and how to fix it”SID History is an attribute used during domain migrations to maintain access to resources in the source domain. While necessary during migrations, persistent SID History on computer accounts can indicate:
- Incomplete migrations: Computers that were migrated but never fully transitioned
- Security risks: SIDs from untrusted or less-secure domains may grant unintended access
- Directory bloat: Unnecessary data in the directory that complicates troubleshooting
- Audit complexity: Makes it harder to determine effective permissions
Control Type
Section titled “Control Type”Detective
Security Recommendation
Section titled “Security Recommendation”- Review computers with SID History to determine if the migration is complete
- Remove SID History attributes once systems are fully migrated and resource access is verified
- Be cautious of SID History containing SIDs from external or untrusted domains
- Document any computers that legitimately require long-term SID History
How the Test Works
Section titled “How the Test Works”This test counts computer objects where the SIDHistory attribute is populated. This attribute typically contains one or more SIDs from the computer’s previous domain(s).
Related Tests
Section titled “Related Tests”Test-MtAdComputerNonStandardGroup- Identifies other migration or configuration anomaliesTest-MtAdComputerDormantCount- Finds stale accounts that may be migration remnants
Related links
Section titled “Related links”- Microsoft Defender for Identity: Unsecure SID History attributes
- ANSSI Active Directory checkpoints: Accounts or groups with SID history set
Mito check. Author: soulemike. Open-source licences.
Open-source licences. CIS Benchmark material © Center for Internet Security, Inc.; CISA SCuBA baselines are public domain (CC0).
© 2026 Virtual Petals. Mito is a Virtual Petals service, hosted in Microsoft Azure UAE North.
