# WMI filter count should be investigated

WMI filter count should be investigated. A Maester check for Active Directory, Group Policy.

Source: https://maester.dev/docs/tests/AD-GPOS-02

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

```powershell title="Run this check"
Invoke-Maester -TestId AD-GPOS-02
```

## Overview

#### Test-MtAdGpoWmiFilterCount

 Counts the number of GPOs that have a non-empty WMI filter.

#### Why This Test Matters
- Operational control: counts GPOs that have a non-empty WMI filter to gauge policy scoping across the environment.

#### Control Type

**Operational**

#### Security Recommendation
- Review configure WMI filters to ensure correct targeting and minimize unnecessary exposure.

#### How the Test Works
- Gets GPO state, computes the number of GPOs with a non-empty WmiFilter, and reports totals and ratios.

#### Related Tests
- `Test-MtAdGpoWmiFilterDetails`.

#### Related links
- [Microsoft Learn - Group Policy management](https://learn.microsoft.com/windows-server/identity/ad-ds/manage/group-policy/group-policy-overview) 
- ANSSI checkpoint: https://www.anssi.gouv.fr/

## Details

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

| Field | Value |
| --- | --- |
| Test ID | AD-GPOS-02 |
| Severity | Info |
| Suite | Active Directory |
| Product | Active Directory |
| Feature | Group Policy |
| Area | Infrastructure hardening |
| Resource type | GroupPolicy |
| MITRE ATT&CK | None |
| PowerShell test | [Test-MtAdGpoWmiFilterCount](https://github.com/maester365/maester/blob/main/tests/ad/gpo-state/Test.AD-GPOS-02.ps1) |
| Services | ActiveDirectory |
| Permissions | ActiveDirectory:Ldap:groupPolicyContainer.gPCFileSysPath:ReadProperty, ActiveDirectory:File:SYSVOL:Read |

</details>

## Source

- Test: [`tests/ad/gpo-state/Test.AD-GPOS-02.ps1`](https://github.com/maester365/maester/blob/main/tests/ad/gpo-state/Test.AD-GPOS-02.ps1)
- Documentation: [`tests/ad/gpo-state/Test.AD-GPOS-02.md`](https://github.com/maester365/maester/blob/main/tests/ad/gpo-state/Test.AD-GPOS-02.md)