# Reversible encryption user count should be retrievable

Reversible password encryption is effectively equivalent to storing passwords in a decryptable form.

Source: https://maester.dev/docs/tests/AD-USER-04

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

```powershell title="Run this check"
Invoke-Maester -TestId AD-USER-04
```

## Overview

Reversible password encryption is effectively equivalent to storing passwords in a decryptable form. Accounts configured this way create serious exposure if the directory or credential material is compromised.

#### Control Type

**Detective**

#### Security Recommendation

Disable reversible password encryption unless it is required for a documented legacy dependency that cannot be modernized immediately. Remediate those dependencies as a priority.

#### How the Test Works

This test retrieves Active Directory user data from `Get-MtADDomainState` and counts accounts with reversible-encryption-style indicators. It checks explicit reversible encryption properties when available and falls back to the relevant `userAccountControl` flag.

#### Related Tests

- `Test-MtAdUserKerberosDesOnlyCount`
- `Test-MtAdUserPasswordNotRequiredCount`
- `Test-MtAdUserNoPreAuthCount`

#### Related links

- [Microsoft Defender for Identity: Unsecure account attributes](https://learn.microsoft.com/defender-for-identity/security-posture-assessments/accounts#unsecure-account-attributes)
- [ANSSI Active Directory checkpoints: Privileged accounts with passwords stored using reversible encryption](https://www.cert.ssi.gouv.fr/uploads/ad_checklist.html#vuln_reversible_password_priv_uac)

## Details

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

| Field | Value |
| --- | --- |
| Test ID | AD-USER-04 |
| Severity | Info |
| Suite | Active Directory |
| Product | Active Directory |
| Feature | Users |
| Area | Authentication |
| Resource type | User |
| MITRE ATT&CK | T1556.005 Reversible Encryption |
| PowerShell test | [Test-MtAdUserReversibleEncryptionCount](https://github.com/maester365/maester/blob/main/tests/ad/user/Test.AD-USER-04.ps1) |
| Services | ActiveDirectory |
| Permissions | ActiveDirectory:Ldap:user:ReadProperty |

</details>

## Source

- Test: [`tests/ad/user/Test.AD-USER-04.ps1`](https://github.com/maester365/maester/blob/main/tests/ad/user/Test.AD-USER-04.ps1)
- Documentation: [`tests/ad/user/Test.AD-USER-04.md`](https://github.com/maester365/maester/blob/main/tests/ad/user/Test.AD-USER-04.md)