Endpoint Manager and Intune Learning Resources for Always On VPN Administrators

Microsoft Endpoint Manager (MEM), formerly Intune, is the recommended solution for deploying and managing Windows Always On VPN client configuration settings. Always On VPN is designed for Mobile Device Management (MDM), with configuration settings deployed specifically to the VPNv2 Configuration Service Provider (CSP) interface.

Resources

Getting up to speed on all things MEM isn’t difficult at all. I’ve found the MEM community to be exceedingly helpful, and there are many available training resources in various formats from which to choose.

Books

The following is a list of Microsoft Endpoint Manager books Always On VPN administrators will find most helpful for learning about MEM.

YouTube

The Intune Training channel on YouTube is an incredibly valuable resource for Always On VPN administrators learning MEM. Hosted by Steven Hosking, Adam Gross, and Ben Reader, there are countless videos covering important MEM configuration tasks.

Pluralsight

Pluralsight offers video training courses for a wide variety of IT-related topics. Recently I published the  Implementing Always On VPN video training course. There are several Microsoft Endpoint Manager video training courses available as well. Pluralsight is available via subscription. You can sign up for a free trial here if you don’t have a subscription.

Conferences

The Midwest Management Summit (MMS) is the premier event for systems management professionals. Their annual conference takes place each spring in the U.S. (Minneapolis, MN). The event is the best place to learn about Microsoft Endpoint Manager and network with systems management professionals worldwide.

Additional Resources

As a reminder, MEM topics such as certificate deployment and Always On VPN profile deployment and management are covered in detail in both my Implementing Always On VPN book and the Implementing Always On VPN video training course on Pluralsight. 😁

Always On VPN Video Training Course on Pluralsight

Implementing Microsoft Windows Always On VPN, my latest video training course on Pluralsight is now available! This course provides comprehensive training for designing, implementing, and supporting a Windows Always On VPN solution. The course is nearly seven hours long (!) and covers all Always On VPN configuration aspects. The video training course covers the following Always On VPN topics.

  • Infrastructure planning and preparation
  • Configuring VPN infrastructure
  • Provisioning Always On VPN clients
  • Advanced configuration
  • Always On VPN in Azure
  • Certificates and Intune
  • High availability
  • Monitoring and reporting
  • Troubleshooting

The Implementing Always On VPN video training course is available to Pluralsight subscribers now. You can sign up for a free trial if you don’t have a subscription. Enjoy!

Additional Information

Implementing Microsoft Windows Always On VPN on Pluralsight

Additional Video Training Courses on Pluralsight

Sign Up for a Free Trial at Pluralsight

Certificate-Based Authentication Changes and Always On VPN

Microsoft introduced important changes affecting certificate-based authentication on Windows domain controllers as part of the May 10, 2022 update KB5014754 that may affect Always On VPN deployments. The update addresses privilege escalation vulnerabilities when a domain controller is processing a certificate-based authentication request. The recommendation from Microsoft is that the update be applied to all Windows domain controllers and Active Directory Certificate Services (AD CS) servers as soon as possible.

Updated 5/20/2022: An out-of-band update to address authentication issues reported with this update is now available. Updates are available for Windows Server 2022, Windows Server 20H2, Windows Server 2019, Windows Server 2016, Windows Server 2012 R2, Windows Server 2012, Windows Server 2008 R2 SP1, and Windows Server 2008 SP2.

Certificate Services

After applying the update to certification authority (CA) servers, a non-critical extension with Object Identifier (OID) 1.3.6.1.4.1.311.25.2 is added to all issued certificates with the user or device security identifier (SID) included. Domain controllers with the update installed will use this information to validate the certificate used for authentication and ensure that it matches the information in Active Directory.

Domain Controllers

The update operates in Compatibility Mode, by default, when applied to domain controllers. Windows monitors authentication requests and records audit events for certificates presented for authentication under the following conditions.

No strong mapping (event ID 39) – The certificate has not been mapped explicitly to a domain account, and the certificate did not include the new SID extension.

Certificate predates account (event ID 40) – A certificate was issued before the user existed in Active Directory, and no explicit mapping could be found.

User’s SID does not match certificate (event ID 41) – A certificate contains the new SID extension, but it does not match the SID of the corresponding user account.

Certificate Mapping

Administrators can map certificates explicitly to accounts in Active Directory, but this results in a significant administrative burden in most environments. A better option is to reissue user and device authentication certificates after applying the KB5014754 update to all issuing CA servers.

Reenroll Certificates

Administrators should reissue user and device authentication certificates after applying the KB5014754 update. Open the Certificate Templates management console (certtmpl.msc), identify the user or device authentication certificate template, then right-click on the template and choose Reenroll All Certificate Holders.

Enforcement Mode

After applying update KB5014754, administrators should monitor domain controller event logs for event IDs 39, 40, and 41. Once all certificates have been updated, and none of these events have been recorded for 30 days, administrators can switch to Full Enforcement Mode by enabling it in the registry on all domain controllers.

Key: HKLM\SYSTEM\CurrentControlSet\Services\KDC
Value: StrongCertificateBindingEnforcement
Type: DWORD
Data: 2

Note: Microsoft will automatically switch to Full Enforcement Mode beginning May 9, 2023.

Known Issues

There have been some reports of authentication issues after installing the KB5014754 update. Early indications are that device authentication certificates missing a Subject Alternative Name (SAN) entry are to blame. Administrators are encouraged to update their device certificates to include the SAN entry. Optionally, but not recommended, administrators can place the update in disabled mode by editing the registry.

Note: An out-of-band update for these authentication issues is now available. See the reference links at the top of this article for more information.

Additional Information

KB5014754 – Certificate-based authentication changes on Windows domain controllers

Microsoft Windows Always On VPN Users Prompted for Certificate

Microsoft Windows Always On VPN Clients Prompted for Authentication when Accessing Internal Resources

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