Recently, a bug in Microsoft 365’s Copilot raised eyebrows across organizations, as it inadvertently led to the summarization of confidential emails. This glitch bypassed data loss prevention policies, putting sensitive information at risk. For those wondering if their data was compromised, this article breaks down the impact, the level of concern warranted, and the steps necessary to safeguard future communications.
What Datapoints Were Leaked?
The Microsoft 365 Copilot bug wasn’t just a minor slip-up. It led to confidential emails, marked with sensitivity labels, getting summarized and exposed to users who shouldn’t have seen them. Here’s what really happened:
Types of Data Exposed
Confidential Email Content: Emails flagged as sensitive or confidential were included in Copilot’s summaries, even if the recipient didn’t have permission to view them.
Internal Discussions: Details from private conversations, project updates, and sometimes personal data inside those emails were at risk.
Metadata Leaks: While the main focus is on email content, some metadata (like subject lines and sender/recipient names) could also have been referenced in the generated summaries.
Microsoft 365 has built-in Data Loss Prevention (DLP) policies. These are supposed to block sensitive data from leaking out, even inside the organization. The Copilot bug managed to sidestep these controls:
Summarization Overrules Labels: Copilot was generating summaries of emails, ignoring the confidentiality labels meant to protect sensitive messages.
Policy Bypass: Instead of DLP stopping the exposure, Copilot’s AI processed and displayed snippets to unauthorized users. This flaw meant the usual safety nets simply didn’t catch the problem.
For any business that relies on labeling and DLP to keep secrets safe, this wasn’t just a technical error—it was a wake-up call. Protecting sensitive information takes more than trusting built-in labels; it means understanding how new AI features interact with security policies.
Should You Be Worried?
Anyone who’s been following the recent Microsoft 365 Copilot bug is right to pause and ask: “Is my data at risk?” It’s a fair question—especially for organizations that trust cloud platforms with sensitive information. Let’s lay out the facts and help you figure out where you stand.
What Happened?
Scope of the Issue: Microsoft reported that a bug in Copilot for Microsoft 365 led to some users seeing file metadata from other tenants. This means names and folder paths—not the actual file content—were potentially visible to unintended parties.
Who Was Impacted? Not every organization or user was affected. According to Microsoft, only a limited subset of users who triggered specific search scenarios might have seen this metadata. There’s no evidence that the bug exposed document contents or allowed unauthorized access to files themselves.
Should You Panic?
No Mass Data Leak: The exposure was limited to metadata. While metadata can sometimes be sensitive, it doesn’t carry the weight of an open document.\
Controlled Response: Microsoft acted fast. They rolled out a fix, notified affected customers, and are still investigating to make sure all angles are covered.
Microsoft’s Communication: They’ve been transparent about the limitations of the exposure, reassuring customers that actual file data stayed locked down.
Microsoft’s Next Steps
Immediate Fix: A patch was deployed to stop the bug in its tracks.
Ongoing Review: The company is reviewing logs and following up with any organization potentially impacted.
User Guidance: Customers have been advised on how to check audit logs and spot any out-of-place access events.
Practical Considerations for Organizations
Audit Your Own Data: Even if you weren’t notified by Microsoft, it’s wise to review your organization’s access logs for peace of mind.
Sensitive Metadata Still Matters: Even if only file names and paths were visible, these can reveal business operations or confidential projects.
Where Cloaked Fits In
For teams handling especially sensitive data, extra layers of privacy go a long way. Tools like Cloaked offer features that help mask, redact, or limit the sharing of file information—metadata included. If your organization needs to minimize exposure risk, even from mishaps outside your control, having a solution that puts privacy front and center can make all the difference.
No one wants to be left guessing about their data’s safety. Staying informed and taking proactive steps, like using privacy-focused solutions, is the surest way to keep a cool head when unexpected bugs pop up.
What Should Be Your Next Steps?
Protecting your organization's email communications demands more than quick fixes. With the Microsoft 365 Copilot bug fresh in everyone’s mind, it’s important to approach email security with both urgency and clarity. Here’s a clear set of actions you should take to safeguard your organization and check if you’ve been affected.
1. Check If You Were Impacted
Review Microsoft Communications: Microsoft has been notifying affected organizations. Check for official notices or updates in your admin portals.
Audit Access Logs: Look for unusual access patterns in your email and document histories. Suspicious logins or unexpected file sharing can be signs of exposure.
Scan for Data Leaks: Use security tools to search for sensitive files or emails that may have been shared externally without proper authorization.
2. Strengthen Your Email Defenses
Enable Multi-Factor Authentication (MFA): This basic step blocks most unauthorized access attempts, even if passwords are compromised.
Review Permissions: Audit who can access what within your Microsoft 365 environment. Limit access to sensitive emails and documents.
Update Software Regularly: Install the latest patches for Microsoft 365 and related tools. Bugs like the Copilot incident are often fixed quickly, but only if you update.
3. Use Security Tools to Stay Ahead
No matter how careful your team is, mistakes and oversights happen. That’s where specialized tools can make all the difference.
Deploy Email Security Platforms: Consider solutions designed to monitor, detect, and block malicious activity in real time.
Automate Threat Detection: Use tools that scan for phishing attempts, unauthorized sharing, or signs of account compromise.
Cloaked: An Extra Layer of Protection
Cloaked’s platform is built to help organizations like yours automatically detect and block suspicious email activities, reducing the risk of sensitive data being exposed. Its advanced monitoring keeps an eye on outgoing communications and alerts you to anything unusual, so you’re not left guessing if you’ve missed something critical.
4. Train Your Team
Run Regular Security Trainings: Teach employees how to spot phishing emails and what to do if they see something suspicious.
Simulate Attacks: Consider periodic tests to gauge your team’s awareness and preparedness.
5. Set Up a Rapid Response Plan
Know Who to Contact: Make sure everyone knows who to notify if there’s a suspected breach.
Document Procedures: Have clear steps written down for investigating and containing incidents.
Staying safe isn’t a one-time task—it’s an ongoing process. With the right steps, vigilance, and tools like Cloaked in your corner, you can significantly reduce the risk of future email breaches.
At Cloaked, we believe the best way to protect your personal information is to keep it private before it ever gets out. That’s why we help you remove your data from people-search sites that expose your home address, phone number, SSN, and other personal details. And to keep your info private going forward, Cloaked lets you create unique, secure emails and phone numbers with one click - so you sign up for new experiences without giving away your real info. With Cloaked, your privacy isn’t a setting - it’s the default. Take back control of your personal data with thousands of Cloaked users.
*Disclaimer: You agree not to use any aspect of the Cloaked Services for FCRA purposes.
