Microsoft 365: Microsoft 365 companion apps- a suite of apps designed to enhance productivity

🚨 The Signal: New Microsoft 365 companion apps (People, File Search, Calendar) integrate with Windows 11, offering quick access to M365 data. This introduces new potential attack surfaces and data exposure vectors for sensitive organisational information.

The Impact

All users are affected by new data access points, increasing the risk of information exposure and unauthorised access.

• End Users: Risk of inadvertent data exposure through simplified access.
• Security Teams: Increased attack surface for data exfiltration and unauthorised access.
• Admins: New endpoints to secure and monitor for compliance.
• Organisations: Potential for data leakage if not properly governed.

The Action

1. Review existing Microsoft 365 data governance policies for companion app compatibility.
2. Assess data access policies for People, File Search, and Calendar apps.
3. Monitor audit logs for unusual activity related to companion app usage.
4. Communicate data handling best practices to end-users regarding new apps.

Domain: M365-Apps · Impact: high · Workload: M365 Apps · Essential Eight: User Application Hardening · ISM: ISM-1412, ISM-1485, ISM-1486, ISM-1542, ISM-1585, ISM-1667, ISM-1668, ISM-1669, ISM-1670, ISM-1823, ISM-1824, ISM-1859, ISM-1860