How to prevent data leakage in collaboration tools like Slack and Teams

In recent years, collaboration tools have become an absolute necessity for remote and hybrid work. This primarily increased during the COVID-19 pandemic due to the impossibility of communicating in person. So, tools like Slack, Microsoft Teams, and Zoom surged in popularity, enabling employees to stay connected despite physical distances.

But this sudden transition to online communication opened up many questions related to security because the vast majority of employees were accessing sensitive information from home networks, opening the door to potential data leaks.

Common causes of data leakage in collaboration tools

Data leaks in collaboration tools can occur for a number of reasons, including:

Misconfigured sharing settings: If permissions for files, channels, or resources are not properly set, it can lead to sensitive information being exposed. For example, if a file containing confidential information is mistakenly shared via a public link, anyone who comes across it can access the file.

Default permissions most often give users access to data that they don’t need to know, so we have cases where new employees are automatically added to various channels or folders that they don’t need access to yet.

Unrestricted third-party integrations: The problem with third-party integrations is that those apps may have access to sensitive information that they shouldn’t:

• Private messages, channels, or documents shared in Slack or Teams.
• Employee personal information, business strategies, or proprietary documents.
• Customer data, including PII (Personally Identifiable Information).

So, if the third-party app has over-permissioned access, it could expose data to unauthorized users.

Lack of visibility and monitoring: Without visibility into how data is shared or accessed, it is difficult to assess whether there has been a data leak or breach. If someone has shared sensitive company information in a public group, it may go unnoticed if no one is monitoring the activities.

Human error: Human error is the most common cause of data leakage. Sharing sensitive information in public channels or with the wrong people are the most common errors that occur due to carelessness, misunderstanding of settings, or negligence. Therefore, education remains the most important way to reduce these mistakes to a minimum.

Enforcing permissions and access controls

To avoid the possibility of data being shared with unauthorized individuals, users should have only the permissions they need to complete a task and nothing more. The best methods for this would be to use role-based access control (RBAC) to grant permissions based on job roles, limit administrative privileges to essential personnel only, and regularly review and adjust user roles to match job responsibilities.

Over time, teams accumulate unused channels, outdated files, and excessive permissions, which can create security risks. To reduce these risks, regularly removing inactive users, outdated files, and unnecessary channels is recommended, along with using compliance reports to monitor file-sharing activity and access history.

External users, such as contractors, vendors, and partners, also pose a danger if their access is not properly controlled, which is why admin approval is important before inviting them to Slack workspaces or Teams channels. The admin should enable time-limited guest access to automatically revoke permissions after a set period and monitor guest activity with audit logs and real-time alerts for unauthorized access.

Monitoring and logging activity

With tools like Slack and Teams, keeping track of what’s happening is key to data protection. By monitoring what’s happening in real time, you can spot if something unusual is going on before before it becomes a bigger problem. Whether it’s tracking who’s sharing which files, catching strange login behavior, or preventing unauthorized access to sensitive data, having the right alerts and tools in place can make a big difference.

Here are some best practices for monitoring and logging activity in collaboration tools like Slack and Teams:

Ensure audit logging is turned on in both Slack and Teams to track user activities. This allows administrators to review logs of actions like file sharing, message editing, and channel changes. This can help identify potential security issues or non-compliant actions.

Configure real-time alerts to notify administrators immediately when suspicious actions occur, such as unauthorized file access, sharing, or editing.

Keep an eye on any unusual behavior, such as file downloads from unfamiliar locations, high-frequency access, or attempts to access sensitive information from untrusted devices or IP addresses. This helps detect compromised accounts or attempts to exfiltrate data.

Implement Cloud Access Security Brokers (CASBs) to enhance security across cloud-based tools. CASBs help enforce security policies, control access, monitor activity, and ensure compliance, especially when external apps or users are involved.

Training employees on secure collaboration to prevent data leakage

Educating users about phishing risks in collaboration tools is key to avoiding data breaches and leaks. If employees know what to look for — suspicious links, unfamiliar sender addresses, and other common phishing tricks — they’re much less likely to fall for these attacks.

It’s also important to train employees on best practices for secure file sharing and external communication. They should be encouraged to use encrypted channels when sharing sensitive data, double-check that permissions are set correctly for shared files, and be mindful of who they share information with, especially external partners. It’s a good idea to remind users to review their access and sharing settings regularly to make sure only the right people have access.

To help employees better understand these concepts, running simulated security exercises is a great way to put their knowledge to the test. Simulations of real-world threats like phishing or unauthorized access attempts help employees practice identifying and responding to security risks, so they’re more confident and effective when a real threat arises.