# Sign-ins detected as high risk SHALL be blocked

Sign-ins detected as high risk SHALL be blocked. A Maester check for Entra ID, Conditional Access.

Source: https://maester.dev/docs/tests/CISA.MS.AAD.2.3

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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><a class="test-byline-avatar" href="/contributors/merill" title="Merill Fernando · Co-contributor"><img src="https://github.com/merill.png" alt="Merill Fernando" 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> with <a href="/contributors/merill">Merill Fernando</a></span><a class="test-byline-link" href="/contributors">All contributors →</a></div></div>

<p class="test-part">Part of <a href="/docs/tests/cisa">CISA</a> · Entra ID · Conditional Access · <a href="/docs/tests">All checks</a></p>

```powershell title="Run this check"
Invoke-Maester -TestId CISA.MS.AAD.2.3
```

## Overview

Sign-ins detected as high risk SHALL be blocked.

Rationale: Blocking high-risk sign-ins may prevent compromised accounts from accessing the tenant.

#### Remediation action:

Create a Conditional Access policy blocking sign-ins determined to be high risk by Microsoft Entra ID Protection. Configure the following policy settings in the new Conditional Access policy as per the values below:

* Users > Include > **All users**
* Target resources > Cloud apps > **All cloud apps**
* Conditions > Sign-in risk > **High**
* Access controls > Grant > **Block Access**

Note: While CISA recommends blocking, the [Microsoft recommendation](https://learn.microsoft.com/entra/id-protection/howto-identity-protection-configure-risk-policies#microsofts-recommendation) is to require multi-factor authentication for high-risk sign-ins.

#### Related links

* [CISA Risk Based Policies - MS.AAD.2.3](https://github.com/cisagov/ScubaGear/blob/main/PowerShell/ScubaGear/baselines/aad.md#msaad23v1)
* [CISA ScubaGear Rego Reference](https://github.com/cisagov/ScubaGear/blob/main/PowerShell/ScubaGear/Rego/AADConfig.rego#L138)

## Details

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

| Field | Value |
| --- | --- |
| Test ID | CISA.MS.AAD.2.3 |
| Severity | High |
| Suite | CISA |
| Product | Entra ID |
| Feature | Conditional Access |
| Area | Access control |
| Resource type | Tenant |
| User impact | Low |
| Implementation cost | Low |
| MITRE ATT&CK | T1078.004 Cloud Accounts |
| Supports benchmark | CISA SCuBA Secure Configuration Baselines for Microsoft 365 (version ScubaGear main, 2026-10-11), requirement MS.AAD.2.3 |
| Criticality | SHALL |
| Upstream requirement | MS.AAD.2.3v1 |
| Supports controls | cisa-scuba:MS.AAD.2.3, nist-800-53-r5:AC-2(12), nist-800-53-r5:AC-2(13) |
| PowerShell test | [Test-MtCisaBlockHighRiskSignIn](https://github.com/maester365/maester/blob/main/tests/cisa/entra/Test.CISA.MS.AAD.2.3.ps1) |
| Services | Graph |
| Compatible licenses | AAD_PREMIUM_P2 |

</details>

## Source

- Test: [`tests/cisa/entra/Test.CISA.MS.AAD.2.3.ps1`](https://github.com/maester365/maester/blob/main/tests/cisa/entra/Test.CISA.MS.AAD.2.3.ps1)
- Documentation: [`tests/cisa/entra/Test.CISA.MS.AAD.2.3.md`](https://github.com/maester365/maester/blob/main/tests/cisa/entra/Test.CISA.MS.AAD.2.3.md)