# Common attachment type filter is enabled

The common attachment type filter can block file types that commonly contain malware, including in internal emails.

Source: https://maester.dev/docs/tests/ORCA.205

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

```powershell title="Run this check"
Invoke-Maester -TestId ORCA.205
```

## Overview

The common attachment type filter can block file types that commonly contain malware, including in internal emails.

#### Remediation action

Enable common attachment type filter.

#### Related Links

* [Configure anti-malware policies](https://aka.ms/orca-mfp-docs-1)
* [Microsoft 365 Defender Portal - Anti-malware](https://security.microsoft.com/antimalwarev2)
* [Recommended settings for EOP and Microsoft Defender for Office 365](https://aka.ms/orca-atpp-docs-6)

## Details

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

| Field | Value |
| --- | --- |
| Test ID | ORCA.205 |
| Severity | Medium |
| Suite | ORCA |
| Product | Defender |
| Related products | Exchange Online |
| Feature | Anti-malware |
| Area | Email and collaboration protection |
| Resource type | Policy |
| User impact | Low |
| Implementation cost | Low |
| MITRE ATT&CK | T1566.001 Spearphishing Attachment, T1204.002 Malicious File |
| Supports controls | nist-800-53-r5:SI-3 |
| PowerShell test | [Test-ORCA205](https://github.com/maester365/maester/blob/main/tests/orca/Test.ORCA.205.ps1) |
| Services | ExchangeOnline |

</details>

## Source

- Test: [`tests/orca/Test.ORCA.205.ps1`](https://github.com/maester365/maester/blob/main/tests/orca/Test.ORCA.205.ps1)
- Documentation: [`tests/orca/Test.ORCA.205.md`](https://github.com/maester365/maester/blob/main/tests/orca/Test.ORCA.205.md)