All posts tagged vulnerability

Always On VPN IKEv2 Security Vulnerability April 2026

Microsoft published its Security Updates for April 2026 today, and the good news is that there are no Windows Server Routing and Remote Access (RRAS) vulnerabilities this month. However, they disclosed a critical remote code execution (RCE) vulnerability that impacts deployments using Internet Key Exchange version 2 (IKEv2).

IKE Service Extensions RCE

CVE-2026-33824 addresses a security vulnerability in the Windows Internet Key Exchange (IKE) Service Extensions. This vulnerability is a Remote Code Execution (RCE) vulnerability, with a CVSS 3.1 base score of 9.8 (Critical). Always On VPN implementations that use the device tunnel or IKEv2 for the user tunnel are affected.

Impact

This vulnerability presents a unique challenge to Always On VPN administrators as IKEv2 is required to support device tunnel connections. Some implementations also use IKEv2 for the user tunnel. In either case, the vulnerable VPN server, often domain-joined, is reachable from the Internet, greatly increasing the attack surface and exposure to this vulnerability.

Recommendations

For deployments that use IKEv2 (device or user tunnel), administrators should update their RRAS server as soon as possible to protect against potential attacks on this service.

Not Using IKEv2?

If you are not using the device tunnel or IKEv2 for the user tunnel, ensure the following IKEv2 ports are blocked at the edge firewall.

  • Inbound UDP port 500 (IKE)
  • Inbound UDP port 4500 (IKE NAT-T)

In addition, consider disabling IKEv2 on the RRAS server by opening an elevated command window and running the following command.

netsh.exe ras set wanports device = "WAN Miniport (IKEv2)" rasinonly = disabled ddinout = disabled ddoutonly = disabled maxports = 0

Optionally, you can use the Routing and Remote Access management console (rrasmgnt.msc) to perform this task.

  1. Right-click on Ports and choose Properties.
  2. Select WAN Miniport (IKEv2).
  3. Click Configure.
  4. Uncheck Remote access connections (inbound only).
  5. Uncheck Demand-dial routing connection (inbound and outbound).
  6. Enter 0 in the Maximum ports field.
  7. Click Ok.

Additional Information

Microsoft Security Updates for April 2026

CVE-2026-33824 – Windows Internet Key Exchange (IKE) Service Extension RCE

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by Richard M. Hicks on April 14, 2026  •  Permalink
Posted in Always On VPN, AOVPN, CVE, device tunnel, Enterprise, enterprise mobility, IKEv2, Infrastructure, Microsoft, Patch Tuesday, RCE, Remote Access, routing and remote access service, RRAS, Security, Security Update, Update, user tunnel, VPN, Vulnerability, Windows 10, Windows 11, Windows Server 2016, Windows Server 2019, Windows Server 2022, Windows Server 2025
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Posted by Richard M. Hicks on April 14, 2026

https://directaccess.richardhicks.com/2026/04/14/always-on-vpn-ikev2-security-vulnerability-april-2026/

Always On VPN Security Updates June 2025

Patch Tuesday is upon us again; thankfully, it’s a light month of Always On VPN administrators. The Microsoft monthly security updates for June 2025 include just a few Windows Routing and Remote Access Service (RRAS) fixes. In addition, an update is available for a vulnerability in the Windows Remote Access Connection Manager. Significantly, DirectAccess administrators are affected this month by a vulnerability identified in the Windows KDC Proxy Service (KPSSVC).

RRAS Updates

The Microsoft security updates for June 2025 address the following CVEs for Windows Server RRAS.

Both RRAS CVEs are Remote Code Execution (RCE) vulnerabilities with max severity ratings of Important.

Remote Access Connection Manager

A security vulnerability in the Windows Remote Access Connection Manager is addressed with the following CVE.

An attacker exploiting this vulnerability could elevate local access privileges.

KDC Proxy

This critical vulnerability affects those organizations still supporting Microsoft DirectAccess in their environments.

This CVE addresses an RCE in the KDC Proxy Service (KPSSVC) that could allow an attacker to execute arbitrary code over the network. DirectAccess administrators are encouraged to apply this update as soon as possible.

Additional Information

Microsoft June 2025 Security Updates

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by Richard M. Hicks on June 10, 2025  •  Permalink
Posted in authentication, KDC Proxy, Microsoft, Remote Access, routing and remote access service, RRAS, Security Update, Update, Windows 10, Windows 11, Windows Server 2016, Windows Server 2019, Windows Server 2022, Windows Server 2025
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Posted by Richard M. Hicks on June 10, 2025

https://directaccess.richardhicks.com/2025/06/10/always-on-vpn-security-updates-june-2025/

Always On VPN Security Updates May 2025

Once again, it’s the second Tuesday of the month, and Microsoft has published its monthly security updates for May 2025. Once again, this month includes many updates for the Windows Server Routing and Remote Access Service (RRAS) and an update for Active Directory Certificate Services (AD CS).

RRAS Updates

The Microsoft security updates for May 2025 address the following CVEs for Windows Server RRAS.

All the reported vulnerabilities in RRAS this month are information disclosure vulnerabilities, with exploitation unlikely. Most appear to be memory-related (null pointer references, out-of-bounds reads, etc.). None are Remote Code Execution (RCE) vulnerabilities, and none are rated Critical.

AD CS Update

This month’s update release also includes a single CVE addressing a denial of service (DoS) vulnerability in AD CS.

Additional Information

Microsoft May 2025 Security Updates

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by Richard M. Hicks on May 13, 2025  •  Permalink
Posted in Always On VPN, AOVPN, CVE, Microsoft, routing and remote access service, RRAS, Security, Security Update, VPN, Vulnerability, Windows 10, Windows 11, Windows Server 2016, Windows Server 2019, Windows Server 2022, Windows Server 2025
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Posted by Richard M. Hicks on May 13, 2025

https://directaccess.richardhicks.com/2025/05/13/always-on-vpn-security-updates-may-2025/

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