# Senders are not being allow listed in an unsafe manner

Emails coming from allow listed senders bypass several layers of protection within Exchange Online Protection.

Source: https://maester.dev/docs/tests/ORCA.109

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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/orca">ORCA</a> · Defender · Anti-spam · <a href="/docs/tests">All checks</a></p>

```powershell title="Run this check"
Invoke-Maester -TestId ORCA.109
```

## Overview

Emails coming from allow listed senders bypass several layers of protection within Exchange Online Protection. If senders are allow listed, they are open to being spoofed from malicious actors.

#### Remediation action

Remove allow listing on senders.

#### Related Links

* [Microsoft 365 Defender Portal - Anti-spam settings](https://security.microsoft.com/antispam)
* [Recommended settings for EOP and Office 365 Microsoft Defender for Office 365 security](https://aka.ms/orca-atpp-docs-6)
* [Use Anti-Spam Policy Sender/Domain Allow lists](https://aka.ms/orca-antispam-docs-4)

## Details

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

| Field | Value |
| --- | --- |
| Test ID | ORCA.109 |
| Severity | Medium |
| Suite | ORCA |
| Product | Defender |
| Related products | Exchange Online |
| Feature | Anti-spam |
| Area | Email and collaboration protection |
| Resource type | Policy |
| User impact | Low |
| Implementation cost | Medium |
| MITRE ATT&CK | T1566 Phishing, T1684.002 Email Spoofing |
| Supports controls | nist-800-53-r5:SI-8 |
| PowerShell test | [Test-ORCA109](https://github.com/maester365/maester/blob/main/tests/orca/Test.ORCA.109.ps1) |
| Services | ExchangeOnline |

</details>

## Source

- Test: [`tests/orca/Test.ORCA.109.ps1`](https://github.com/maester365/maester/blob/main/tests/orca/Test.ORCA.109.ps1)
- Documentation: [`tests/orca/Test.ORCA.109.md`](https://github.com/maester365/maester/blob/main/tests/orca/Test.ORCA.109.md)