# (L2) Ensure anonymous users can't join a meeting

Anonymous users are people who join a meeting without signing in to Microsoft Teams.

Source: https://maester.dev/docs/tests/CIS.M365.8.5.1

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<div class="test-byline"><div class="test-byline-avatars"><a class="test-byline-avatar test-byline-avatar--author" href="/contributors/jeremyfinney-lgtm" title="jeremy finney · Original author"><img src="https://github.com/JeremyFinney-lgtm.png" alt="jeremy finney" 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/jeremyfinney-lgtm">jeremy finney</a></span><a class="test-byline-link" href="/contributors">All contributors →</a></div></div>

<p class="test-part">Part of <a href="/docs/tests/cis">CIS</a> · Teams · Meetings · <a href="/docs/tests">All checks</a></p>

```powershell title="Run this check"
Invoke-Maester -TestId CIS.M365.8.5.1
```

## Overview

Anonymous users are people who join a meeting without signing in to Microsoft Teams. If anonymous users can join, anyone who has the meeting link, or who finds it forwarded or posted in public, can attend and listen to or take part in confidential discussions.

Turning off anonymous join keeps meetings limited to people who have signed in. Users who must attend without an account can still be invited through a supported path, such as a guest account.

#### Remediation action

1. Sign in to the [Microsoft Teams admin center](https://admin.teams.microsoft.com).
2. Go to **Meetings** > **Meeting policies**.
3. Open the **Global (Org-wide default)** policy.
4. Under **Anonymous users can join a meeting**, select **Off**.
5. Select **Save**.

##### PowerShell

1. Connect to Teams PowerShell using `Connect-MicrosoftTeams`.
2. Run the following command:

```powershell
Set-CsTeamsMeetingPolicy -Identity Global -AllowAnonymousUsersToJoinMeeting $false
```

#### Related links

* [Microsoft Teams admin center](https://admin.teams.microsoft.com)
* [Manage meeting policies in Microsoft Teams](https://learn.microsoft.com/microsoftteams/meeting-policies-in-teams)
* [Set-CsTeamsMeetingPolicy](https://learn.microsoft.com/powershell/module/teams/set-csteamsmeetingpolicy)
* [CIS Microsoft 365 Foundations Benchmark v7.0.0 - 8.5.1](https://www.cisecurity.org/benchmark/microsoft_365)

## Details

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

| Field | Value |
| --- | --- |
| Test ID | CIS.M365.8.5.1 |
| Severity | Medium |
| Suite | CIS |
| Product | Teams |
| Feature | Meetings |
| Area | External access and sharing |
| Resource type | Tenant |
| User impact | Medium |
| Implementation cost | Low |
| MITRE ATT&CK | None |
| Supports benchmark | CIS Microsoft 365 Foundations Benchmark (version 7.0.0), requirement 8.5.1 |
| Benchmark level | L2 |
| Benchmark profiles | E3 Level 2 |
| Supports controls | cis-m365:8.5.1, nist-800-53-r5:AC-3 |
| PowerShell test | [Test-MtCisTeamsAnonymousJoin](https://github.com/maester365/maester/blob/main/tests/cis/Test.CIS.M365.8.5.1.ps1) |
| Services | Teams |

</details>

## Source

- Test: [`tests/cis/Test.CIS.M365.8.5.1.ps1`](https://github.com/maester365/maester/blob/main/tests/cis/Test.CIS.M365.8.5.1.ps1)
- Documentation: [`tests/cis/Test.CIS.M365.8.5.1.md`](https://github.com/maester365/maester/blob/main/tests/cis/Test.CIS.M365.8.5.1.md)