# Password reversible encryption should be disabled

Reversible encryption for passwords is one of the most dangerous settings in Active Directory:

Source: https://maester.dev/docs/tests/AD-PWDPOL-05

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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 · Password policy · <a href="/docs/tests">All checks</a></p>

```powershell title="Run this check"
Invoke-Maester -TestId AD-PWDPOL-05
```

## Overview

Reversible encryption for passwords is one of the most dangerous settings in Active Directory:

- **Complete password exposure**: Unlike one-way hashes, reversible encryption allows passwords to be decrypted by anyone with access to the encryption key
- **Domain compromise risk**: If an attacker gains access to the domain, they can extract all passwords stored with reversible encryption
- **No security benefit**: This setting exists only for legacy application compatibility and provides no security benefit

**This setting should never be enabled** in a production environment. If legacy applications require it, consider alternative authentication methods or application modernization.

#### Control Type

**Preventive**

#### Security Recommendation

**Disable reversible encryption immediately** unless you have a documented, approved exception for a specific legacy application.

To verify and configure this setting:
1. Open **Group Policy Management**
2. Navigate to the Default Domain Policy
3. Edit: Computer Configuration > Policies > Windows Settings > Security Settings > Account Policies > Password Policy
4. Ensure **Store passwords using reversible encryption** is **Disabled**

If you find this enabled:
- Document all affected user accounts
- Identify which applications require this setting
- Plan migration to modern authentication methods
- Disable the setting and reset all affected passwords

#### How the Test Works

This test retrieves the default domain password policy using `Get-ADDefaultDomainPasswordPolicy` and checks the `ReversibleEncryptionEnabled` property. The test reports:
- Whether reversible encryption is currently enabled or disabled
- Recommended setting (Disabled)
- Critical security warning if enabled

#### Related Tests

- `Test-MtAdPasswordComplexityRequired` - Checks password complexity requirements
- `Test-MtAdPasswordMinLength` - Checks minimum password length

## Details

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

| Field | Value |
| --- | --- |
| Test ID | AD-PWDPOL-05 |
| Severity | Medium |
| Suite | Active Directory |
| Product | Active Directory |
| Feature | Password policy |
| Area | Authentication |
| Resource type | Tenant |
| User impact | Medium |
| Implementation cost | Medium |
| MITRE ATT&CK | T1556.005 Reversible Encryption |
| PowerShell test | [Test-MtAdPasswordReversibleEncryption](https://github.com/maester365/maester/blob/main/tests/ad/password-policy/Test.AD-PWDPOL-05.ps1) |
| Services | ActiveDirectory |
| Permissions | ActiveDirectory:Ldap:domainDNS.pwdProperties:ReadProperty |

</details>

## Source

- Test: [`tests/ad/password-policy/Test.AD-PWDPOL-05.ps1`](https://github.com/maester365/maester/blob/main/tests/ad/password-policy/Test.AD-PWDPOL-05.ps1)
- Documentation: [`tests/ad/password-policy/Test.AD-PWDPOL-05.md`](https://github.com/maester365/maester/blob/main/tests/ad/password-policy/Test.AD-PWDPOL-05.md)