Microsoft Teams and SharePoint have quietly become the backbone of how businesses communicate and store information. In many organizations, these tools have replaced file servers, shared drives, and even parts of email. But in 2025, companies are discovering something important: Teams and SharePoint can create serious security risks when they’re not managed properly.
Most businesses didn’t roll out Microsoft 365 with a long-term governance plan. They turned it on, created a few Teams, built some SharePoint sites, and let people get to work. Over time, the environment grew — and now it contains years of data, sharing links, chat history, and access permissions that no one is actively reviewing.
This is where the hidden risks come from.
Teams and SharePoint grow faster than anyone expects
Every time someone starts a new project, creates a department Team, or shares a file, Microsoft 365 creates new spaces, new groups, and new permissions. It feels seamless, but it all adds up.
By 2025, most businesses are facing:
- dozens (or hundreds) of old Teams no one uses
- files shared with former employees or old vendors
- SharePoint libraries full of outdated or duplicate information
- overly permissive links (“anyone with this link can view”)
- chat messages containing sensitive data
- external guests with long-forgotten access
- Teams created for one-time conversations that still exist
None of this is unusual — but it opens the door to data exposure if attackers compromise an account or if someone shares the wrong link with the wrong person.
Compromised accounts spread faster inside Teams
Most business email compromise (BEC) used to take place inside Outlook. Now, attackers target Teams just as aggressively.
In 2025, we’re seeing attackers:
- join active Teams channels and read sensitive conversations
- browse SharePoint libraries through Teams
- impersonate internal users to request documents
- upload malicious files to shared channels
- use Teams chats to bypass email filters
- quietly pull down large sets of files from Channels and SharePoint
If your environment is cluttered and permissions are loose, attackers have a lot more room to move.
SharePoint oversharing is still one of the biggest risks
One of the most misunderstood features in Microsoft 365 is file sharing. It’s easy to send a link, but the default settings often grant more access than people intend.
By the time we run an audit, it’s common to find:
- files open to “anyone with the link”
- links shared outside the organization without review
- project folders accessible to entire departments unnecessarily
- sensitive data saved in personal OneDrive accounts
- external users who still have access from years ago
These issues frequently go unnoticed until something bad happens — or until an auditor or cyber insurer asks difficult questions.
Getting Teams and SharePoint under control in 2025
A modern cleanup involves:
- Reviewing external and guest access
Remove anyone who shouldn’t still be connected. - Reducing sharing link permissions
Switch “anyone with the link” to organization-only or specific people. - Archiving or deleting old Teams
Unused collaboration spaces create unnecessary exposure. - Auditing file access and sensitive data locations
Understand where your important documents actually live. - Enabling sensitivity labels and DLP policies
Let Microsoft 365 help protect files automatically. - Regular access reviews
Permissions shouldn’t be permanent unless they need to be.
The bottom line
Teams and SharePoint have become essential business tools — but they grow quickly and quietly. Without proper oversight, they create hidden risks that are easy to miss until they become a problem.
A small amount of governance goes a long way. Businesses that clean up their environment in 2025 see stronger security, fewer surprises, and a more organized digital workspace that supports how teams actually work today.