GIFShell attack secure your business!

A vulnerability has been discovered across the GIFfy used in Microsoft Teams. This attack allows hackers to use Microsoft Teams to execute phishing-style attacks and allows commands to be executed secretly to steal information and/or data, thanks to a GIF in a conversation.

Source:

HERE
or again
ICI

Until Microsoft releases a fix, I would advise you to completely disable the ability to use GIFs in Teams.

To do so, go to your Teams Admin Center portal. There are two places to go to modify it:

1. Users > Guest access
   In the messaging section, deactivate Giphy in conversations

   

2. In Messaging Policies, disablethe Giphy in conversations option.