# SMBv1 should be disabled on all domain controllers

SMBv1 (Server Message Block version 1) is an outdated protocol with significant security vulnerabilities:

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

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

## Overview

SMBv1 (Server Message Block version 1) is an outdated protocol with significant security vulnerabilities:

- **EternalBlue exploit**: Used in WannaCry and NotPetya ransomware attacks
- **No encryption**: SMBv1 traffic is not encrypted
- **No integrity checks**: Vulnerable to man-in-the-middle attacks
- **Deprecated by Microsoft**: Microsoft strongly recommends disabling SMBv1

Domain controllers with SMBv1 enabled pose a critical security risk as they are high-value targets for attackers.

#### Control Type

**Preventive**

#### Security Recommendation

**Disable SMBv1 on all domain controllers immediately.**

To disable SMBv1 on a domain controller:
```powershell
#### Check current status
Get-SmbServerConfiguration | Select-Object EnableSMB1Protocol

#### Disable SMBv1
Set-SmbServerConfiguration -EnableSMB1Protocol $false -Force

#### Disable SMBv1 feature (requires restart)
Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol
```

#### How the Test Works

This test queries the SMB server configuration on each domain controller to check if SMBv1 protocol is enabled. It reports:
- Number of DCs with SMBv1 enabled
- Names of affected DCs
- Overall security status

#### Related Tests

- `Test-MtAdDcSmbSigningEnabledCount` - SMB signing configuration
- `Test-MtAdDcSmbv311EnabledCount` - SMBv3.1.1 protocol status

## Details

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

| Field | Value |
| --- | --- |
| Test ID | AD-DC-02 |
| Severity | High |
| Suite | Active Directory |
| Product | Active Directory |
| Feature | Domain controllers |
| Area | Infrastructure hardening |
| Resource type | DomainController |
| User impact | Low |
| Implementation cost | Medium |
| MITRE ATT&CK | T1210 Exploitation of Remote Services |
| Supports controls | nist-800-53-r5:CM-7 |
| PowerShell test | [Test-MtAdDcSmbv1EnabledCount](https://github.com/maester365/maester/blob/main/tests/ad/domain-controller/Test.AD-DC-02.ps1) |
| Services | ActiveDirectory |
| Permissions | ActiveDirectory:Remoting:Microsoft.PowerShell, ActiveDirectory:Cim:root\Microsoft\Windows\SMB:MSFT_SmbServerConfiguration:Read |

</details>

## Source

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