Turn off meeting chat for anonymous participants

Description

Meeting chat is on for everyone except anonymous participants (MeetingChatEnabledType = EnabledExceptAnonymous), or off (Disabled), in every meeting policy. Anonymous participants who are admitted cannot read or post chat messages.

Rationale

Meeting chat often carries documents, links and decisions that outlive the meeting. An anonymous participant has no accountable identity and can use the chat to post phishing links that look like part of the meeting. Removing chat for anonymous participants limits both exposure and abuse while keeping audio, video and screen sharing.

Impact

Anonymous participants (for example customers without an account) cannot use the chat, including to ask questions; use Q&A or invite them as guests. None known for authenticated participants.

Applies when

Requires: Microsoft Teams

Setting

Audit

1. Sign in to the Microsoft Teams admin center (https://admin.teams.microsoft.com) as at least a Global Reader.
2. Browse to Meetings > Meeting policies and open the Global (Org-wide default) policy, then every custom policy assigned to users.
3. In the Meeting engagement section, check that Meeting chat is On for everyone but anonymous users or Off.
4. With Microsoft Teams PowerShell (Global Reader is enough): Get-CsTeamsMeetingPolicy | Select-Object Identity, MeetingChatEnabledType.
5. Fail if any policy returns Enabled.

Remediation

1. In the Teams admin center, browse to Meetings > Meeting policies and open the Global (Org-wide default) policy.
2. In the Meeting engagement section, set Meeting chat to On for everyone but anonymous users and Save. Role: Teams Administrator.
3. Repeat for each custom policy, unless a documented exception applies to its users.
4. PowerShell equivalent: Set-CsTeamsMeetingPolicy -Identity Global -MeetingChatEnabledType EnabledExceptAnonymous (repeat with -Identity <policy> for custom policies). Changes can take up to 24 hours to apply.

References

• Set-CsTeamsMeetingPolicy Microsoft, vendor-doc, accessed 2026-10-24
• Teams settings and policies reference Microsoft, vendor-doc, accessed 2026-10-24

Mappings

How this control relates to the other framework's: equivalent, stricter, looser, partial or related.

Threats mitigated

Related controls

• related CB-M365-COLLAB-023 Prevent anonymous participants from joining Teams meetings
• related CB-M365-COLLAB-030 Block chat in external meetings hosted by untrusted organizations

People and lifecycle