Security News > 2021 > June > Microsoft Teams: Very Bad Tabs Could Have Led to BEC

Such attacks could be carried out via a malicious Microsoft Teams tab and Power Automate flows, Grant explained.

Ca organization - can create a malicious Teams tab and use it to "Eventually steal emails, Teams messages and files from gooduser(at)fakecorp.ca, and send emails and messages on their behalf."

As Grant detailed, Microsoft Teams has a default feature that allows a user to launch small apps as a tab in any team they belong to.

If a given user is part of an Office 365/Teams organization with a Business Basic license or above, they can also access a set of Teams tabs that consist of Microsoft Power Apps applications.

When a user launches their first Power App tab, it creates what Microsoft calls a "Dataverse for Teams Environment," which Microsoft says is used to store, manage and share team-specific data, apps and flows.

Teams tabs generally open an iFrame to a page that the app's manifest lists as a trusted domain.

News URL

https://threatpost.com/microsoft-teams-tabs-bec/166909/