Guest accounts can be easily created through Teams, which can allow hackers to incite users to click on malicious links or socially engineer them. The best practice is to allow guest users to only attend meetings in Teams. This setting will prevent guest users from sending private messages, sharing their screens, or calling other users. Guests will not be able to sign in to Teams using their guest account.
In the Set section, you can configure one of the following options when you apply the setting:
- Block Guests: Guests can't sign in to Teams using their guest account
- Control Guests Access: Guests will be able to sign-in to Teams using their guest accounts and attend meetings, but they will not be able to chat or call privately, share their screen and use the MeetNow feature.
- Allow Guests: Guests will be able to sign-in to Teams using their guest accounts and attend meetings, chat and call privately, share their screen and use the MeetNow feature.
- Do not modify (Ignore): Office Protect will not monitor nor attempt to modify the setting on the organization. We recommend using this option if your organization has a specific Guests Access configuration.
Please note that changes on this setting might take some time to take effect.
You can find this setting in the Teams admin center > Users > Guests Access.
Microsoft’s Documentation:
https://learn.microsoft.com/en-US/microsoftteams/guest-access