# Schema modification year details should be retrievable

Detailed visibility into schema modifications by year provides a comprehensive timeline of your Active Directory's evolution.

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

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

## Overview

Detailed visibility into schema modifications by year provides a comprehensive timeline of your Active Directory's evolution. This information is valuable for:

- **Capacity planning**: Understanding growth patterns of the directory
- **Change management**: Tracking when major applications were deployed
- **Security auditing**: Identifying unauthorized or unexpected schema changes
- **Compliance reporting**: Documenting directory modifications for auditors

Unexpected spikes in schema modifications may indicate:
- Unauthorized application deployments
- Malicious schema extensions
- Improper testing procedures
- Lack of change control

#### Control Type

**Operational**

#### Security Recommendation

Establish monitoring for schema changes:
- **Alert on schema modifications**: Configure alerts when schema changes occur
- **Regular reviews**: Periodically review schema modification history
- **Access controls**: Limit Schema Admins group membership
- **Audit logging**: Enable auditing for schema changes

#### How the Test Works

This test analyzes schema objects and groups them by creation year, providing:
- Count of schema objects created per year
- Percentage distribution across years
- Timeline of directory evolution

#### Related Tests

- `Test-MtAdSchemaModificationYearCount` - Shows count of years with modifications
- `Test-MtAdSchemaVersionEntryCount` - Shows current schema version
- `Test-MtAdSchemaVersionDetails` - Provides comprehensive schema details

## Details

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

| Field | Value |
| --- | --- |
| Test ID | AD-SCH-02 |
| Severity | Info |
| Suite | Active Directory |
| Product | Active Directory |
| Feature | Schema |
| Area | Infrastructure hardening |
| Resource type | Tenant |
| MITRE ATT&CK | None |
| PowerShell test | [Test-MtAdSchemaModificationYearDetails](https://github.com/maester365/maester/blob/main/tests/ad/schema/Test.AD-SCH-02.ps1) |
| Services | ActiveDirectory |
| Permissions | ActiveDirectory:Ldap:Schema/*:ReadProperty |

</details>

## Source

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