Always On VPN Security Updates July 2025

Patch Tuesday has arrived, and, unlike last month, it’s a busy month for Always On VPN administrators. The June 2025 Microsoft security updates address a whopping 16 (!) vulnerabilities in the Windows Routing and Remote Access Service (RRAS). Notably, DirectAccess administrators are once again impacted by a critical vulnerability in the Windows KDC Proxy Service (KPSSVC) this month.

RRAS

As stated previously, this month’s update addresses 16 unique CVEs in Windows Server RRAS. All are memory-related buffer overflows and out-of-bounds reads, indicating that a security researcher was recently probing for vulnerabilities in RRAS.

While all the above CVEs are Remote Code Execution (RCE) and Information Disclosure vulnerabilities, none are rated as Critical; all are rated as Important. This means exploitation is unlikely, but administrators are encouraged to update as soon as possible.

KDC Proxy

This month’s security update includes another Critical RCE in the Windows KDC Proxy Service (KPSSVC).

The KDC Proxy is enabled by default when DirectAccess is configured. By design, this means the service is exposed to the public Internet, posing a significant risk to organizations using DirectAccess for secure remote access. Administrators are urged to update their systems immediately to avoid compromise.

Additional Information

Microsoft July 2025 Security Updates

Always On VPN Device Tunnel Fails to Connect Automatically

After the April 2024 Microsoft security updates were released, many Always On VPN administrators noticed that the device tunnel suddenly stopped connecting automatically for many, if not all, their endpoints.

Note: There were additional problems with the April 2024 security update that affected the Always On VPN device tunnel. Details here.

Troubleshooting

When this problem occurs, administrators can establish the device tunnel connection successfully if it is initiated manually. This indicates that there are no issues with the IKEv2 VPN connection or security configuration.

Subscription Activation

The root cause of this issue is related to a subscription activation issue broken in the April 2024 security updates. In this case, Windows 10/11 Enterprise Edition devices that were initially provisioned using Professional Edition and used a step-up upgrade (subscription activation) to Enterprise Edition are reverting to Professional Edition. The Always On VPN device tunnel requires Enterprise Edition to work correctly. Although you can deploy a device tunnel to Windows Professional, it will not connect automatically. It will, however, connect manually.

KB5040527

On July 25, 2024, Microsoft released a preview of updates (KB5040527), including a fix for this subscription activation issue. Administrators experiencing problems with Always On VPN device tunnels where their devices revert to Professional Edition can install this update to resolve this issue.

Additional Information

Always On VPN Device Tunnel Issue with the Microsoft April 2024 Security Update

Always On VPN Device Tunnel Status Indicator

Always On VPN Devcie Tunnel Only Deployment Considerations