Microsoft Teams has become the default communication hub for millions of businesses, and that includes a lot of sensitive information flowing through chat messages, shared files, and meeting recordings. The convenience is undeniable, but we regularly find businesses using Teams without any of the security controls that Microsoft built into the platform.
What’s at Risk in Your Teams Environment
Think about what your team shares in Teams on a typical day: client contracts, financial spreadsheets, passwords (yes, people still do this), employee HR documents, and confidential business strategy. All of this lives in your Microsoft 365 tenant, and anyone with access to the right Team or channel can see it.
The risk isn’t just external hackers. It’s also employees who have access to channels they don’t need, former employees whose access wasn’t revoked promptly, and guest users from vendors or clients who were given broad access for a project that ended months ago.
Microsoft 365 Security Features You Should Enable
Data Loss Prevention (DLP) policies automatically detect when someone tries to share sensitive data like credit card numbers, Social Security numbers, or health records through Teams. You can configure DLP to block the message, warn the sender, or notify an administrator. Most businesses with Microsoft 365 Business Premium already have access to DLP but never turned it on.
Sensitivity labels classify and protect documents based on their confidentiality level. A document labeled “Confidential” can be automatically encrypted and prevented from being forwarded or downloaded outside your organization. These labels follow the document everywhere, even if someone saves it to a USB drive.
Conditional access policies control where and how people can access Teams. You can require MFA for external access, block logins from countries where you don’t do business, and prevent unmanaged devices from downloading files.
Managing Guest Access Safely
Guest access in Teams is essential for working with clients and vendors, but it creates security gaps if not managed properly. Review your guest settings to control what external users can see, which channels they can join, and whether they can share files.
Set expiration dates for guest accounts so access is automatically revoked after a project ends. We find orphaned guest accounts in almost every Microsoft 365 environment we audit. Some businesses have guest users from vendors they stopped working with two years ago still able to access shared files.
Meeting and Recording Security
Teams meetings are another area where sensitive information leaks. Enable the meeting lobby by default so uninvited participants can’t join without approval. Restrict who can record meetings and where recordings are stored. Set up retention policies for meeting recordings so they’re automatically deleted after a defined period rather than sitting in SharePoint indefinitely.
For businesses in regulated industries like healthcare or finance, configure meeting compliance recording if your license supports it. This captures all meetings for audit purposes while ensuring recordings are stored in a compliant, tamper-proof location.
Teams Security Quick Wins
You can significantly improve your Teams security this week with a few configuration changes: enable MFA for all users (if you haven’t already), review and remove unnecessary guest accounts, disable external sharing for channels that contain sensitive data, turn on audit logging so you can see who accessed what, and create a clear policy that prohibits sharing passwords or sensitive credentials through chat.
These settings exist in your Microsoft 365 admin center right now, waiting to be configured. If you’re not sure where to find them or how to set them up properly, your IT provider can implement all of these in a single afternoon.
