Security News > 2022 > September > Microsoft Teams stores auth tokens as cleartext in Windows, Linux, Macs

Security analysts have found a severe security vulnerability in the desktop app for Microsoft Teams that gives threat actors access to authentication tokens and accounts with multi-factor authentication turned on.

The newly discovered security issue impacts versions of the application for Windows, Linux, and Mac and refers to Microsoft Teams storing user authentication tokens in clear text without protecting access to them.

An attacker with local access on a system where Microsoft Teams is installed could steal the tokens and use them to log into the victim's account.

Microsoft Teams is an Electron app, meaning that it runs in a browser window, complete with all the elements required by a regular web page.

Vectra analyzed Microsoft Teams while trying to find a way to remove deactivated accounts from client apps, and found an ldb file with access tokens in clear text.

With a patch unlikely to be released, Vectra's recommendation is for users to switch to the browser version of the Microsoft Teams client.

News URL

https://www.bleepingcomputer.com/news/security/microsoft-teams-stores-auth-tokens-as-cleartext-in-windows-linux-macs/