# Alerts SHALL be enabled

At a minimum, the following alerts SHALL be enabled: - Suspicious email sending patterns detected. - Suspicious Connector Activity.

Source: https://maester.dev/docs/tests/CISA.MS.EXO.16.1

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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/thomas-s-schmidt" title="Thomas Schmidt · Co-contributor"><img src="https://github.com/thomas-s-schmidt.png" alt="Thomas Schmidt" 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/thomas-s-schmidt">Thomas Schmidt</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 · Alert policies · <a href="/docs/tests">All checks</a></p>

```powershell title="Run this check"
Invoke-Maester -TestId CISA.MS.EXO.16.1
```

## Overview

At a minimum, the following alerts SHALL be enabled:
- Suspicious email sending patterns detected.
- Suspicious Connector Activity.
- Suspicious Email Forwarding Activity.
- Messages have been delayed.
- Tenant restricted from sending unprovisioned email.
- Tenant restricted from sending email.
- A potentially malicious URL click was detected.

Rationale: Potentially malicious or service impacting events may go undetected without a means of detecting these events. Setting up a mechanism to alert administrators to events listed above draws attention to them to help minimize impact to users and the agency.

#### Remediation action:

1. Sign in to **Microsoft 365 Defender**.
2. Under **Email & collaboration**, select **Policies & rules**.
3. Select [**Alert Policy**](https://security.microsoft.com/alertpoliciesv2).
4. Select the checkbox next to each alert to enable as determined by the agency and at a minimum those referenced in the [CISA M365 Security Configuration Baseline for Exchange Online](https://github.com/cisagov/ScubaGear/blob/main/PowerShell/ScubaGear/baselines/exo.md#msexo161v1) which are:
    - Suspicious email sending patterns detected.
    - Suspicious connector activity.
    - Suspicious Email Forwarding Activity.
    - Messages have been delayed.
    - Tenant restricted from sending unprovisioned email.
    - Tenant restricted from sending email.
    - A potentially malicious URL click was detected.
5. Click the pencil icon from the top menu.
6. Select the **Enable selected policies** action from the **Bulk actions** menu.

#### Related links

* [Defender admin center - Alert policy](https://security.microsoft.com/alertpoliciesv2)
* [CISA 16 Alerts - MS.EXO.16.1](https://github.com/cisagov/ScubaGear/blob/main/PowerShell/ScubaGear/baselines/exo.md#msexo161v1)
* [CISA ScubaGear Rego Reference](https://github.com/cisagov/ScubaGear/blob/main/PowerShell/ScubaGear/Rego/EXOConfig.rego#L863)

## Details

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

| Field | Value |
| --- | --- |
| Test ID | CISA.MS.EXO.16.1 |
| Severity | High |
| Suite | CISA |
| Product | Exchange Online |
| Related products | Defender |
| Feature | Alert policies |
| Area | Logging and detection |
| Resource type | Policy |
| User impact | Low |
| Implementation cost | Low |
| MITRE ATT&CK | T1114.003 Email Forwarding Rule, T1204.001 Malicious Link |
| Supports benchmark | CISA SCuBA Secure Configuration Baselines for Microsoft 365 (version ScubaGear main, 2026-10-11), requirement MS.EXO.16.1 |
| Criticality | SHALL |
| Upstream requirement | Moved to MS.SECURITYSUITE.4.1v1 (was MS.EXO.16.1v1) |
| Supports controls | cisa-scuba:MS.EXO.16.1, nist-800-53-r5:SI-4(5) |
| PowerShell test | [Test-MtCisaExoAlert](https://github.com/maester365/maester/blob/main/tests/cisa/exchange/Test.CISA.MS.EXO.16.1.ps1) |
| Services | ExchangeOnline, Graph, SecurityCompliance |
| Compatible licenses | ATP_ENTERPRISE |

</details>

## Source

- Test: [`tests/cisa/exchange/Test.CISA.MS.EXO.16.1.ps1`](https://github.com/maester365/maester/blob/main/tests/cisa/exchange/Test.CISA.MS.EXO.16.1.ps1)
- Documentation: [`tests/cisa/exchange/Test.CISA.MS.EXO.16.1.md`](https://github.com/maester365/maester/blob/main/tests/cisa/exchange/Test.CISA.MS.EXO.16.1.md)