# Trusted root CA count should be retrievable

Trusted root CAs act as the trust anchors for an entire PKI trust chain.

Source: https://maester.dev/docs/tests/AD-CFG-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 · Certificate Services · <a href="/docs/tests">All checks</a></p>

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

## Overview

Trusted root CAs act as the trust anchors for an entire PKI trust chain. If an attacker (or a misconfiguration) introduces an unauthorized trusted root CA, they may be able to construct certificates that validate through the trust chain, enabling broad compromise of authentication, TLS validation, and signed trust decisions.

#### Control Type

**Operational**

#### Security Recommendation
- Maintain an allowlist of trusted root CAs and require strong change control for trust additions/removals.
- Restrict permissions on PKI trust anchor configuration to only PKI administrators.
- After any change, verify certificate thumbprints/subjects, revocation publication, and distribution behavior.
- Alert on unexpected changes in the number of trusted root CAs.

#### How the Test Works
- Enumerates trusted root CA entries published in Active Directory (trust anchor objects).
- Counts the number of trusted root CAs.
- Compares the observed count to an environment baseline and flags unexpected increases/decreases.

#### Related Tests
- [Test-MtAdEnrollmentCaCertificateDetails](/docs/commands/Test-MtAdEnrollmentCaCertificateDetails): Validates CA certificate validity and identity details.
- [Test-MtAdEnterpriseCaCount](/docs/commands/Test-MtAdEnterpriseCaCount): Confirms which CAs are configured for enrollment across the environment.

## Details

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

| Field | Value |
| --- | --- |
| Test ID | AD-CFG-16 |
| Severity | Info |
| Suite | Active Directory |
| Product | Active Directory |
| Feature | Certificate Services |
| Area | Infrastructure hardening |
| Resource type | CertificateAuthority |
| MITRE ATT&CK | None |
| PowerShell test | [Test-MtAdTrustedRootCaCount](https://github.com/maester365/maester/blob/main/tests/ad/config/Test.AD-CFG-16.ps1) |
| Services | ActiveDirectory |
| Permissions | ActiveDirectory:Ldap:Configuration/*:ReadProperty |

</details>

## Source

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