# Mailbox auditing SHALL be enabled

Rationale: Exchange Online user accounts can be compromised or misused.

Source: https://maester.dev/docs/tests/CISA.MS.EXO.13.1

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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><a class="test-byline-avatar" href="/contributors/merill" title="Merill Fernando · Co-contributor"><img src="https://github.com/merill.png" alt="Merill Fernando" 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> with <a href="/contributors/merill">Merill Fernando</a></span><a class="test-byline-link" href="/contributors">All contributors →</a></div></div>

<p class="test-part">Part of <a href="/docs/tests/cisa">CISA</a> · Exchange Online · Mailbox auditing · <a href="/docs/tests">All checks</a></p>

```powershell title="Run this check"
Invoke-Maester -TestId CISA.MS.EXO.13.1
```

## Overview

Mailbox auditing SHALL be enabled.

Rationale: Exchange Online user accounts can be compromised or misused. Enabling mailbox auditing provides a valuable source of information to detect and respond to mailbox misuse.

#### Remediation action

Mailbox auditing can be managed from the [Exchange Online PowerShell module](https://learn.microsoft.com/microsoft-365/compliance/audit-mailboxes?view=o365-worldwide). Follow the instructions listed on Manage mailbox auditing in Office 365.

1. To enable mailbox auditing by default for your organization via PowerShell:
2. Connect to the Exchange Online PowerShell.
3. Run the following command:
    `Set-OrganizationConfig –AuditDisabled $false`

#### Related links

* [Microsoft Learn - Mailbox Auditing](https://learn.microsoft.com/microsoft-365/compliance/audit-mailboxes?view=o365-worldwide)
* [CISA 13 Mailbox Auditing - MS.EXO.13.1v1](https://github.com/cisagov/ScubaGear/blob/main/PowerShell/ScubaGear/baselines/exo.md#msexo131v1)
* [CISA ScubaGear Rego Reference](https://github.com/cisagov/ScubaGear/blob/main/PowerShell/ScubaGear/Rego/EXOConfig.rego#L741)

## Details

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

| Field | Value |
| --- | --- |
| Test ID | CISA.MS.EXO.13.1 |
| Severity | High |
| Suite | CISA |
| Product | Exchange Online |
| Feature | Mailbox auditing |
| Area | Logging and detection |
| Resource type | Tenant |
| User impact | Low |
| Implementation cost | Low |
| MITRE ATT&CK | T1070.008 Clear Mailbox Data, T1098.002 Additional Email Delegate Permissions, T1564.008 Email Hiding Rules, T1586.002 Email Accounts, T1685.002 Disable or Modify Cloud Log |
| Supports benchmark | CISA SCuBA Secure Configuration Baselines for Microsoft 365 (version ScubaGear main, 2026-10-11), requirement MS.EXO.13.1 |
| Criticality | SHALL |
| Upstream requirement | MS.EXO.13.1v1 |
| Supports controls | cisa-scuba:MS.EXO.13.1, nist-800-53-r5:AU-12c |
| PowerShell test | [Test-MtCisaMailboxAuditing](https://github.com/maester365/maester/blob/main/tests/cisa/exchange/Test.CISA.MS.EXO.13.1.ps1) |
| Services | ExchangeOnline |

</details>

## Source

- Test: [`tests/cisa/exchange/Test.CISA.MS.EXO.13.1.ps1`](https://github.com/maester365/maester/blob/main/tests/cisa/exchange/Test.CISA.MS.EXO.13.1.ps1)
- Documentation: [`tests/cisa/exchange/Test.CISA.MS.EXO.13.1.md`](https://github.com/maester365/maester/blob/main/tests/cisa/exchange/Test.CISA.MS.EXO.13.1.md)