CIS.M365.8.5.8 - (L2) Ensure external meeting chat is off
Overview
External meeting chat lets your users read and write chat messages in meetings that are hosted by organizations you have no trusted relationship with. Messages from untrusted senders can carry phishing links or malicious files into a meeting that your users are attending.
Turning this off keeps your users out of the chat in meetings hosted by untrusted organizations. Users can still chat in meetings hosted by your organization and by trusted organizations.
Remediation action
- Sign in to the Microsoft Teams admin center.
- Go to Meetings > Meeting policies.
- Open the Global (Org-wide default) policy.
- Under External meeting chat, select Off.
- Select Save.
PowerShell
- Connect to Teams PowerShell using
Connect-MicrosoftTeams. - Run the following command:
Set-CsTeamsMeetingPolicy -Identity Global -AllowExternalNonTrustedMeetingChat $false
Related links
- Microsoft Teams admin center
- Manage meeting policies in Microsoft Teams
- Set-CsTeamsMeetingPolicy
- CIS Microsoft 365 Foundations Benchmark v7.0.0 - 8.5.8
Test Metadata
| Field | Value |
|---|---|
| Test ID | CIS.M365.8.5.8 |
| 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 | T1566 Phishing |
| Supports benchmark | CIS Microsoft 365 Foundations Benchmark (version 7.0.0), requirement 8.5.8 |
| Benchmark level | L2 |
| Benchmark profiles | E3 Level 2 |
| Supports controls | cis-m365:8.5.8, nist-800-53-r5:AC-3 |
| PowerShell test | Test-MtCisTeamsExternalMeetingChat |
| Services | Teams |
Source
- Test:
tests/cis/Test.CIS.M365.8.5.8.ps1 - Documentation:
tests/cis/Test.CIS.M365.8.5.8.md