# Built-in administrator account count should be investigated

Built-in and critical administrator-related accounts are among the most sensitive identities in Active Directory.

Source: https://maester.dev/docs/tests/AD-USER-22

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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 · Users · <a href="/docs/tests">All checks</a></p>

```powershell title="Run this check"
Invoke-Maester -TestId AD-USER-22
```

## Overview

Built-in and critical administrator-related accounts are among the most sensitive identities in Active Directory. Attackers frequently target these accounts because they provide durable, high-impact access.

- **High-value targets**: RID 500 accounts are especially attractive to attackers.
- **Detection support**: Helps validate whether renamed administrator accounts still exist.
- **Tier-0 review**: Critical system objects warrant extra monitoring and protection.

#### Control Type

**Operational**

#### Security Recommendation

- Minimize use of built-in administrator accounts.
- Monitor all RID 500 activity closely.
- Apply strong credential protection and privileged access controls.
- Review critical system accounts for expected state and usage.

#### How the Test Works

This test counts user objects whose SID ends in `-500` or are marked as `isCriticalSystemObject`.

#### Related Tests

- `Test-MtAdUserBuiltInAdminEnabledDetails`
- `Test-MtAdUserBuiltInAdminLastLogonDetails`
- `Test-MtAdUserBuiltInAdminPasswordAgeDetails`

## Details

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

| Field | Value |
| --- | --- |
| Test ID | AD-USER-22 |
| Severity | Info |
| Suite | Active Directory |
| Product | Active Directory |
| Feature | Users |
| Area | Privileged access |
| Resource type | User |
| MITRE ATT&CK | T1078.001 Default Accounts |
| PowerShell test | [Test-MtAdUserBuiltInAdminCount](https://github.com/maester365/maester/blob/main/tests/ad/user/Test.AD-USER-22.ps1) |
| Services | ActiveDirectory |
| Permissions | ActiveDirectory:Ldap:user:ReadProperty |

</details>

## Source

- Test: [`tests/ad/user/Test.AD-USER-22.ps1`](https://github.com/maester365/maester/blob/main/tests/ad/user/Test.AD-USER-22.ps1)
- Documentation: [`tests/ad/user/Test.AD-USER-22.md`](https://github.com/maester365/maester/blob/main/tests/ad/user/Test.AD-USER-22.md)