Strong Certificate Mapping for Intune PKCS and SCEP Certificates

Always On VPN LockDown Mode

With the October 2024 Intune update, Microsoft introduced support for strong certificate mapping for certificates issued by Intune via the Intune Certificate Connector. Enabling strong certificate mapping support in Intune is an important change for those organizations using Microsoft Intune to issue and manage certificates for their users and devices, as it resolves a critical implementation blocker.

Note: This post was updated to clarify that adding the {{OnPremisesSecurityIdentifier}} for PKCS certificates is not required. This variable is only used for SCEP certificates.

Background

In May 2022, Microsoft released security update KB5014754, which added functionality to domain controllers and enterprise issuing certification authority (CA) servers, allowing the Kerberos Key Distribution Center (KDC) to enforce strong certificate mapping. Specifically, with KB5014754 installed, issuing CAs now add the requesting principal’s Security Identifier (SID) to the certificate in a new certificate extension. Domain controllers can be configured to reject authentication requests using certificates that do not include this information.

Today, DCs with KB5014754 installed will still allow authentication without strong certificate mapping. However, Microsoft has stated they will begin enforcing strong certificate mapping in February 2025, with an option to disable it via the registry. Starting in September 2025, full enforcement will be mandatory.

Reference: https://support.microsoft.com/en-us/topic/kb5014754-certificate-based-authentication-changes-on-windows-domain-controllers-ad2c23b0-15d8-4340-a468-4d4f3b188f16

Limitation

The initial changes in KB5014754 applied only to online certificate templates, meaning those that build the subject name from Active Directory. However, deploying certificates with Intune using either PKCS or SCEP requires using an offline certificate template that allows the requestor to supply the subject name in the request. When using offline templates, a certificate is issued but does not embed the SID in the certificate. Using offline templates presents unique challenges to organizations moving to modern management with Intune and Entra ID.

Intune Changes

The October 2024 Intune update addresses this limitation by providing a method to include SID information in certificates using either SCEP or PKCS.

SCEP

To include the SID information in SCEP certificates, create or edit an existing SCEP device configuration policy and define a URI Subject Alternative Name (SAN) attribute with the value {{OnPremisesSecurityIdentifier}} as shown here.

PKCS

To include SID information in PKCS certificates, administrators must ensure the Intune Certificate Connector is updated to at least version 6.2406.0.1001. In addition, a registry setting must be enabled on the Intune Certificate Connector server.

On the server where the Intune Certificate Connector is installed, open the registry editor, navigate to HKLM\Software\Microsoft\MicrosoftIntune\PFXCertificateConnector, and change the value of EnableSidSecurityExtension to 1.

Optionally, administrators can update this setting at the command line by running the following PowerShell command.

Set-ItemProperty -Path ‘HKLM:\SOFTWARE\Microsoft\MicrosoftIntune\PFXCertificateConnector’ -Name EnableSidSecurityExtension -Value 1 -Force

Once complete, restart the Intune Certificate Connector server for the changes to take effect.

Certificates

SID information is added to certificates differently depending on which Intune device configuration policy type is used.

PCKS

PKCS certificates have the SID embedded in the certificate extension 1.3.6.1.4.1.311.25.2, as shown here.

SCEP

SCEP certificates have the SID embedded in the Subject Alternative Name (SAN) field in the format “tag:microsoft.com,2022-09-14:sid:<SID>” as shown here.

Migration

When making these changes to embed the SID in Intune-issued certificates in an existing Intune PKCS or SCEP configuration policy, the change will only affect certificates issued after the change is made. To update all certificate holders, you must create and deploy a new device configuration policy to targeted users or devices. Deleting the old profile (or ensuring it no longer applies) will remove the old certificate from the endpoint. If you’ve configured your Intune Certificate Connector to support revocation, the old certificate will also be revoked.

Entra Conditional Access

Entra Conditional Access certificates have included SID information since July 2023. More details here.

Intune Cloud PKI

The changes above will also work with certificates issued by Cloud PKI for Intune.

Other Cloud PKI Providers

Many other Cloud PKI providers, such as SCEPman and KEYTOS, already include the embedded SID in their certificates. Other cloud PKI providers may also include embedded SID. Consult your provider to confirm.

Additional Information

Microsoft Intune October 2024 Strong Certificate Mapping Update

Microsoft Intune Certificate Connector Strong Certificate Mapping Update for PKCS

Entra ID Conditional Access Certificates with SID Information Now Available

Implementing Strong Certificate Mapping in Microsoft Intune PKCS and SCEP Certificates

Certificate-Based Authentication Changes and Always On VPN

Microsoft Intune Learning Resources for Always On VPN Administrators

Note: This post has been updated and republished to reflect the return to the Microsoft Intune product name and to include updated learning resources for Always On VPN administrators.

Microsoft 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.

ViaMonstra Online Academy

I will be delivering the Mastering Certificates with Microsoft Intune training course at the ViaMonstra online training academy May 14-16, 2024. This three-day live, interactive training course provides a comprehensive deep dive into all aspects of deploying and managing digital certificates using Microsoft Intune. Microsoft Cloud PKI will also be covered. Space is limited, so register today!

Additional Resources

As a reminder, Microsoft Intune 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 DPC with Intune

In the past, I’ve written about PowerON Platforms’ Always On VPN Dynamic Profile Configurator (DPC), a software solution administrators can use to provision and manage Always On VPN client configuration settings using Active Directory and group policy. In addition to streamlining the deployment and management of Always On VPN client settings, DPC has many advanced features and capabilities to ensure optimal security, performance, and connection reliability.

Optimizations

Many settings required to fine-tune and optimize Always On VPN connections are not exposed in the Intune UI or XML. They must be configured by manipulating configuration files, setting registry keys, and running PowerShell commands. Much of this can be automated using Intune Proactive Remediation, but it is far from ideal. Administrators must configure Always On VPN using one method, then deploy optimizations using another. In addition, Proactive Remediation suffers from timing issues where some settings are not applied immediately, resulting in degraded or inoperable VPN connections until changes take effect.

Always On VPN DPC

Always On VPN DPC allows administrators to configure many advanced settings quickly and conveniently using the familiar Group Policy Management console (gpmc.msc). DPC dramatically reduces the administrative burden associated with Always On VPN client management. In addition, DPC enables many of these options by default, ensuring optimal security and reliable operation. Also, DPC immediately implements all configuration settings, eliminating the need to reboot to apply configuration changes.

Intune and ADMX

Historically, Always On VPN DPC could only be used when managing endpoints exclusively with Active Directory group policy. However, DPC can now be used with Microsoft Endpoint Manager/Intune thanks to a new feature that allows administrators to import custom ADMX and ADML administrative templates to Microsoft Endpoint Manager (MEM).

Note: This feature is in public preview at the time of this writing.

DPC and Intune

The combination of DPC and Intune brings with it many advantages. Using DPC with Microsoft Endpoint Manager/Intune offers administrators simplified deployment and many advanced features provided by Always On VPN DPC. In addition, customers who have deployed DPC on-premises can now migrate seamlessly to Microsoft Endpoint Manager/Intune management without giving up DPC’s valuable features.

Learn More

Enter your contact details in the form below for more information regarding Always On VPN DPC. Also, visit https://aovpndpc.com/ to register for a free Always On VPN DPC trial.

Additional Information

Always On VPN with Active Directory Group Policy

Introduction to Always On VPN DPC

Always On VPN DPC Advanced Features

Always On VPN DPC Video Demonstrations

What’s New in Always On VPN DPC v3.0

Always On VPN DPC Free Trial