Microsoft Windows: Updates to address compromised eMudhra certificate authority keys

🚨 The Signal: Microsoft is blocking compromised eMudhra certificate authority keys in Windows, Edge, and WebView2. This prevents attackers from impersonating trusted CAs, maintaining system integrity and trust in digital communications.

The Impact

Organizations using Windows, Edge, or WebView2 are affected by a critical certificate authority compromise, requiring validation of certificate chains.

• Windows users: Potential trust issues with certificates from compromised CAs.
• Microsoft Edge users: Browsing disruptions due to blocked TLS certificates.
• WebView2 users: Application failures if relying on affected certificates.
• Disconnected devices: Requires manual updates to maintain security posture.

The Action

1. Identify if your organization uses certificates chaining to eMudhra CAs.
2. For disconnected Windows devices, manually update the Disallowed Certificate Trust List.
3. For disconnected Azure VMs, ensure certificate trust lists are updated.
4. Verify certificate chains for all internal and external services.

Domain: Other · Impact: high · Workload: Other · Essential Eight: Patch Operating Systems, User Application Hardening · ISM: ISM-1407, ISM-1412, ISM-1485, ISM-1486, ISM-1501, ISM-1542, ISM-1585, ISM-1621, ISM-1622, ISM-1623, ISM-1654, ISM-1655, ISM-1667, ISM-1668, ISM-1669, ISM-1670, ISM-1694, ISM-1695, ISM-1696, ISM-1701, ISM-1702, ISM-1823, ISM-1824, ISM-1859, ISM-1860, ISM-1877, ISM-1889, ISM-1902