Always On VPN October 2023 Security Updates

Once again, it’s time to patch! After several quiet months, there are a few crucial updates Always On VPN administrators will want to get deployed soon. Thankfully, the impact of the security updates related to Always On VPN is low this time, as there is only one Remote Code Execution (RCE) vulnerability, and it’s for a legacy protocol that should be in limited use today.

IKEv2

CVE-2023-36726 addresses a security vulnerability in Windows Internet Key Exchange (IKE) that can lead to privilege escalation. An attacker who successfully exploits this vulnerability can elevate privileges to that of the local SYSTEM.

L2TP

This month’s update discloses several Layer Two Tunneling Protocol (L2TP) vulnerabilities. The following CVEs all address a vulnerability where an attacker can send a specially crafted protocol message to a Windows Routing and Remote Access Service (RRAS) server, which could lead to remote code execution on the server.

Mitigation

The impact of the L2TP security vulnerabilities should be minimal in most organizations. L2TP is a legacy VPN protocol not commonly used for Always On VPN. However, misconfiguration can leave vulnerable RRAS servers exposed. Administrators must ensure that inbound UDP port 1723 is not open from the Internet. In addition, L2TP should be disabled on the RRAS server if not in use. See the article on the May 2023 security updates for details.

Additional Information

October 2023 Security Updates

Always On VPN Disconnects in Windows 11

Always On VPN administrators migrating their endpoints to Windows 11 may encounter a scenario where Always On VPN randomly disconnects when the VPN profile is deployed using Microsoft Intune. The same configuration deployed to Windows 10 devices works reliably, however. In addition, Always On VPN profiles deployed using PowerShell (natively or with SCCM) or Dynamic Profile Configurator (DPC) do not experience this problem.

Troubleshooting

Administrators troubleshooting this issue will find the root cause is associated with the Always On VPN profiles being removed and replaced each time the device syncs with Intune. This occurs even if there are no changes to the configuration. Removing and replacing the Always On VPN profiles on each device sync is unnecessary, of course, but is also highly disruptive to connected users.

Intune and XML

The Intune team identified the issue, and a fix was made available in the August update. However, many of you have reported the issue persists with some Windows 11 clients after installing the latest updates. Further investigation indicates that although the issue has been resolved when using Intune and the native VPN device configuration profile template, the problem still occurs when using the Custom device configuration template.

Workaround

Microsoft is aware of the issues with deploying Always On VPN client configuration settings using XML in Intune, but there’s no indication when or if they will fix it. Until then, administrators have two options to address this problem.

Native VPN Template

When deploying Always On VPN client configuration settings to Windows 11 endpoints, use the native VPN device configuration template, as shown here.

Using the native VPN template does have some limitations, however. The following settings are not exposed using the native VPN template and can only be configured using XML.

XML

If you must use XML, I’ve had some success by ensuring the order and syntax of XML settings is exactly as Intune expects. Follow the steps below to confirm the XML settings order in your XML configuration file.

  1. Deploy your XML file with Intune.
  2. Run Get-VpnClientProfileXML.ps1 to extract the deployed XML settings.
  3. Compare the order of settings to your existing XML.
  4. Compare the syntax of all settings. For example, the <Servers> section should list the server FQDN twice, separated by a semi-colon.
  5. Make changes to ensure all settings in your XML are in the same order as the extracted XML.
  6. Publish a new XML configuration file using Intune and test.

I’ll caution you that this workaround doesn’t always work reliably. Some customers report that this solved their problems entirely, while others have indicated it does not. My testing shows the same results. Let us know in the comments below if this works for you!

Reference XML

I have published an Always On VPN XML configuration file on GitHub for reference. It includes all common settings using the order and syntax required to ensure reliable operation. As a reminder, the sample file includes many settings that aren’t required. It is published as guidance for reference only.

Additional Information

Always On VPN Windows 11 Issues with Intune

Always On VPN PowerShell Script Issues in Windows 11

Windows Server 2012 and 2012 R2 End of Life

DirectAccess on Microsoft Windows

I want to remind you of a critical upcoming milestone that may affect your business. In just 60 days, we will reach the end of support for Windows Server 2012 and Windows Server 2012 R2. As of October 10, 2023, these operating systems will no longer receive security updates or technical support from Microsoft.

End of Support

End of support means your servers will be more vulnerable to security risks and potential threats. It is essential to take action now to ensure your IT infrastructure’s continued security and stability. Upgrading to newer, supported operating systems will protect your data and systems from potential cyber threats and provide access to enhanced features and performance improvements.

Don’t Wait

Now is the time to migrate those remaining workloads for those still running Windows Server 2012 and 2012 R2! Consider the following commonly deployed services that may still be running on Windows Server 2012 or 2012 R2 in your organization.

Remote Access – Windows Server Routing and Remote Access Service (RRAS) is commonly deployed to provide secure remote access for field-based workers. In addition, Absolute Secure Access (formerly NetMotion Mobility) is a widely implemented premium alternative to RRAS. Organizations may be hesitant to migrate these workloads because disrupting remote workers is painful.

DirectAccess – This remote access technology is widely deployed and extremely difficult to migrate. In addition, the complex nature of DirectAccess, with its many intricate interdependencies, poses a significant challenge to organizations migrating this role.

PKI – This is likely the most common enterprise service to be found running on Windows Server 2012 and 2012R2. Most organizations relying on Windows Active Directory Certificate Services (AD CS) to issue and manage enterprise certificates are reluctant to move this workload once it is deployed. This service is much easier to migrate than you might think! It can be done without disruption as well.

Consulting Services

We understand that upgrading might require careful planning and coordination, and our team is here to support you throughout the transition process. Don’t delay – take this opportunity to safeguard your organization’s data and systems by upgrading to the latest Windows Server version or exploring cloud-based solutions.

Get In Touch

Please don’t hesitate to contact us for further assistance or any questions regarding the upgrade process. Together, let’s ensure your business remains secure and productive. You can get started today by booking a free one-hour consultation to discuss your migration strategy. Just fill out the form below and I’ll provide more information.