AD-USER-13 - User SID History count should be retrievable

Contributed by Michael Soule with 2 co-contributorsAll contributors →

Overview

SIDHistory is commonly used during migrations so users can retain access to resources secured with legacy SIDs. Long-term SID history can create unnecessary complexity and unintended access paths.

• Migration artifact detection: Identifies users that may still carry legacy identities
• Trust boundary review: Helps spot cross-domain access dependencies
• Permission cleanup: Supports least-privilege remediation after migrations

Security Recommendation

• Review users with SIDHistory to confirm ongoing business need
• Remove unnecessary SID history entries after resource migration is complete
• Pay special attention to SIDs originating from external or less-trusted domains

How the Test Works

This test counts user objects where the SIDHistory attribute contains one or more values.

Related Tests

• Test-MtAdUserNonStandardPrimaryGroupCount - Finds other migration or provisioning anomalies
• Test-MtAdUserAdminCountCount - Helps prioritize review of privileged accounts

Related links

• Microsoft Defender for Identity: Unsecure SID History attributes
• ANSSI Active Directory checkpoints: Accounts or groups with SID history set

Test Metadata

Field	Value
Test ID	AD-USER-13
Severity	Medium
Suite	Active Directory
Category	AD.User
PowerShell test	Test-MtAdUserSidHistoryCount
Tags	AD, AD-USER-13, AD.User

Source

• Pester test: tests/ad/user/Test-MtAdUserSidHistoryCount.Tests.ps1
• PowerShell source: powershell/public/ad/user/Test-MtAdUserSidHistoryCount.ps1