Teams Administrators Gain Control Over Malicious File Attachments

Microsoft is enhancing security in Microsoft Teams by allowing administrators to control which file extensions are blocked from chats and channels. This change extends the existing Weaponizable File Protection system, which prevents users from sending files with malicious extensions.

Until now, Microsoft has maintained a list of restricted extensions. With this update, administrators will be able to customize which file types Teams blocks or continue using Microsoft's recommended default list.

The feature is expected to apply across all Teams clients, including desktop, web, macOS, Android, and iOS. It is currently in development with general availability scheduled for November 2026.

This flexibility could be particularly valuable in highly regulated organizations and sectors operating critical infrastructure, where a file format that appears benign may carry greater risk.