# Unresolved SID details should be investigated

Knowing which directory objects contain orphaned SID ACEs helps target cleanup work where it matters most.

Source: https://maester.dev/docs/tests/AD-DACL-16

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<div class="test-byline"><div class="test-byline-avatars"><a class="test-byline-avatar test-byline-avatar--author" href="/contributors/soulemike" title="Michael Soule · Original author"><img src="https://github.com/soulemike.png" alt="Michael Soule" width="28" height="28" loading="lazy" decoding="async" /></a></div><div class="test-byline-meta"><span class="test-byline-text">Contributed by <a href="/contributors/soulemike">Michael Soule</a></span><a class="test-byline-link" href="/contributors">All contributors →</a></div></div>

<p class="test-part">Part of <a href="/docs/tests/ad">Active Directory</a> · Active Directory · Permissions and delegation · <a href="/docs/tests">All checks</a></p>

```powershell title="Run this check"
Invoke-Maester -TestId AD-DACL-16
```

## Overview

Knowing which directory objects contain orphaned SID ACEs helps target cleanup work where it matters most.

- **Object-focused remediation**: Grouping unresolved SIDs by object shows exactly where stale ACEs exist
- **Audit clarity**: Makes manual DACL review easier during privileged access assessments
- **Change tracking**: Helps confirm whether decommissioned identities still linger on important objects

#### Control Type

**Operational**

#### Security Recommendation

- Remove orphaned ACEs after confirming the referenced SID is no longer valid
- Prioritize cleanup on privileged OUs, admin groups, and delegation-heavy containers
- Document recurring sources of unresolved SIDs to improve identity lifecycle processes

#### How the Test Works

This test reads `$adState.DaclEntries`, filters unresolved `IdentityReference` values that begin with `S-1-5-21`, and groups them by `ObjectDN`.

#### Related Tests

- `Test-MtAdDaclUnresolvedSidCount` - Counts unresolved SID references
- `Test-MtAdDaclNonInheritedAceCount` - Counts explicit ACEs that may require review
- `Test-MtAdDaclInheritedObjectTypeDetails` - Shows inheritance targeting across ACEs

> **Note:** This test is `LongRunning`. It loads the full DACL dataset, which can consume significant memory in large Active Directory environments. Use `Invoke-Maester -IncludeLongRunning` to run it.

## Details

<details>
<summary>Every attribute of this check</summary>

| Field | Value |
| --- | --- |
| Test ID | AD-DACL-16 |
| Severity | Info |
| Suite | Active Directory |
| Product | Active Directory |
| Feature | Permissions and delegation |
| Area | Access control |
| Resource type | Permission |
| MITRE ATT&CK | None |
| PowerShell test | [Test-MtAdDaclUnresolvedSidDetails](https://github.com/maester365/maester/blob/main/tests/ad/dacl/Test.AD-DACL-16.ps1) |
| Services | ActiveDirectory |
| Permissions | ActiveDirectory:Ldap:*.ntSecurityDescriptor:ReadControl |
| Long running | Yes |

</details>

## Source

- Test: [`tests/ad/dacl/Test.AD-DACL-16.ps1`](https://github.com/maester365/maester/blob/main/tests/ad/dacl/Test.AD-DACL-16.ps1)
- Documentation: [`tests/ad/dacl/Test.AD-DACL-16.md`](https://github.com/maester365/maester/blob/main/tests/ad/dacl/Test.AD-DACL-16.md)