Outlook: Summarize email attachments with Copilot

🚨 The Signal: Copilot in Outlook can now summarise email attachments (PDF, Word, PowerPoint). This increases data exposure risk as sensitive information in attachments can be extracted and potentially misused via Copilot interactions.

The Impact

All users with Copilot access are affected, increasing the risk of sensitive information leakage from attachments.

• End Users: Risk of inadvertently exposing sensitive attachment data through Copilot prompts.
• Security Teams: Increased surface area for data exfiltration and compliance breaches.
• Data Owners: Reduced control over the dissemination of information within attachments.
• Compliance Officers: New vector for non-compliance with data handling regulations.

The Action

1. Review and reinforce existing Microsoft Purview Data Loss Prevention (DLP) policies to detect and prevent sensitive information sharing via Copilot.
2. Implement or update sensitivity labels in Microsoft Purview for documents that may be attached to emails, ensuring appropriate protection.
3. Educate users on responsible Copilot usage, specifically warning against summarising highly sensitive attachments.
4. Monitor Copilot interaction logs for unusual activity or attempts to summarise sensitive documents (if logging is available and configured).
5. Assess the necessity of Copilot access for users handling highly sensitive information and consider scope adjustments.

Domain: Agentic-AI · Impact: high · Workload: M365 Apps