# Average group membership changes per year should be investigated

Understanding the rate of group membership changes provides insights into:

Source: https://maester.dev/docs/tests/AD-GCHG-01

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

```powershell title="Run this check"
Invoke-Maester -TestId AD-GCHG-01
```

## Overview

Understanding the rate of group membership changes provides insights into:

- **Operational tempo**: How frequently group memberships change
- **Security monitoring**: Baseline for detecting anomalous activity
- **Compliance trends**: Track changes over time for audit purposes
- **Change management**: Identify periods of high activity
- **Lifecycle management**: Understand group creation and modification patterns

#### Control Type

**Operational**

#### Security Recommendation

Monitor group membership changes for security anomalies:
- Establish baselines for normal change rates
- Alert on changes that exceed normal thresholds
- Review spikes in activity for unauthorized changes
- Correlate group changes with change management tickets
- Implement approval workflows for privileged group changes
- Document business reasons for high-volume change periods

#### How the Test Works

This test analyzes group metadata to calculate:
- Total groups in the directory
- Timespan since oldest group was created
- Average number of group modifications per year
- Breakdown of creations and modifications by year
- Groups modified within `RecentModificationDays` (default 90)

The analysis helps identify trends and patterns in group management activity.

#### Related Tests

- `Test-MtAdGroupPrivilegedWithMembersDetails` - Reviews current privileged group state
- `Test-MtAdGroupEmptyNonPrivilegedDetails` - Identifies potentially stale groups

## Details

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

| Field | Value |
| --- | --- |
| Test ID | AD-GCHG-01 |
| Severity | Info |
| Suite | Active Directory |
| Product | Active Directory |
| Feature | Groups |
| Area | Identity lifecycle and hygiene |
| Resource type | Group |
| MITRE ATT&CK | None |
| PowerShell test | [Test-MtAdGroupChangeAveragePerYear](https://github.com/maester365/maester/blob/main/tests/ad/group/Test.AD-GCHG-01.ps1) |
| Services | ActiveDirectory |
| Permissions | ActiveDirectory:Ldap:group:ReadProperty |

</details>

## Source

- Test: [`tests/ad/group/Test.AD-GCHG-01.ps1`](https://github.com/maester365/maester/blob/main/tests/ad/group/Test.AD-GCHG-01.ps1)
- Documentation: [`tests/ad/group/Test.AD-GCHG-01.md`](https://github.com/maester365/maester/blob/main/tests/ad/group/Test.AD-GCHG-01.md)