Microsoft Cloud PKI for Intune SCEP URL

Earlier this year, Microsoft announced Cloud PKI for Intune, a cloud service for issuing and managing digital certificates for Intune-managed endpoints. With Cloud PKI for Intune, administrators no longer need to deploy on-premises infrastructure to use certificates for user and device-based authentication for workloads such as Wi-Fi and VPN. Cloud PKI for Intune can be used standalone (cloud native) or integrated with an existing on-premises Active Directory Certificate Services (AD CS) enterprise PKI to extend an existing on-premises certificate services infrastructure.

Provisioning

Cloud PKI for Intune utilizes Simple Certificate Enrollment Protocol (SCEP) to enroll certificates for users and devices. To deploy Intune Cloud PKI certificates, administrators must create and deploy a SCEP Certificate device configuration policy in Intune.

SCEP URL

When creating the SCEP certificate device configuration policy in Intune, administrators are asked to supply the SCEP server URL. Administrators will find this information by opening the Intune management console, navigating to Tenant Administration > Cloud PKI, clicking on the issuing certification authority, and then clicking Properties.

Administrators may notice the URL is unreachable if they try to connect to it using their web browser or PowerShell. Specifically, the FQDN is not shown in the URI; instead, it is represented as the variable {{CloudPKIFQDN}}, as highlighted above.

Policy Configuration

You can safely ignore this as it is not an error or misconfiguration. Simply copy and paste the entire URL into your SCEP certificate device configuration profile as is. Intune in the background will convert this to a fully formed URL with a proper FQDN accessible from the public Internet. This variable is used because it allows Microsoft to use different resources dynamically according to geography and availability.

Additional Information

RFC 8894 – Simple Certificate Enrollment Protocol

Microsoft Cloud PKI for Intune

Microsoft Cloud PKI for Intune and Active Directory

Microsoft Cloud PKI for Intune and Certificate Templates

Troubleshooting Intune Failed PKCS Request

Always On VPN administrators deploying on-premises enterprise PKI certificates using Microsoft Intune with PKCS may encounter a scenario where a certificate fails to be issued to a user or device. In this post, I’ll share some things to investigate when troubleshooting this issue.

Event 1001

To begin, open the Event Log and navigate to Applications and Services > Microsoft > Intune > CertificateConnectors > Admin. You will likely find an event ID 1001 from the CertificateConnectors source with the following error message.

Failed to process PKCS request.

Prerequisites

Validate the following prerequisites have been met on the issuing Certification Authority (CA) server.

Certificate Template

Ensure the certificate template used for PKCS has the correct permissions and is published on an issuing CA server. Open the Certificate Templates management console (certtmpl.msc), right-click the certificate template, choose Properties, and then click on the Security tab. The certificate template must grant the Intune Certificate connector server’s computer account (or the PKCS connector’s service account if running as a service and not SYSTEM) the Read and Enroll permissions on the template.

CA Permissions

In addition to the permissions on the certificate template, ensure the correct permissions have been configured on the issuing CA itself. Right-click on the CA in the Certification Authority management console (certsrv.msc) and choose Security. Ensure the Intune Certificate connector server’s computer account (or the PKCS connector’s service account, if running as a service and not SYSTEM) is granted The Issue and Manage Certificates and Request Certificates permissions.

Intune Policy

Ensure the Intune device configuration policy is configured correctly. These three fields are critical and can result in failed PKCS certificate deployment if misconfigured.

Certification Authority

Enter the fully qualified domain name (FQDN) of the on-premises issuing CA server in this field.

Certification Authority Name

Enter the common name of the issuing CA in this field. You will find this information by running the following command on any domain-joined Windows system.

certutil.exe -dump

Certificate Template Name

Enter the name of the certificate template in Active Directory. Be aware that the template name and template display name are two different things. The template name is usually the template display name without spaces. However, that’s not a guarantee. On the General tab of the certificate template, look at the template name field on the certificate template to confirm.

Summary

This article is not a comprehensive troubleshooting guide for problems associated with failed PKCS certificate deployment using the Microsoft Intune Certificate connector and PKCS. However, it covers some of the more common problems administrators will likely encounter. If you cannot provision PKCS certificates correctly, drop me a note and I’ll provide further guidance.

Additional Information

Troubleshooting Failed Intune Certificate Connector Configuration – Part 1

Troubleshooting Failed Intune Certificate Connector Configuration – Part 2

Intune Certificate Connector Service Account and PKCS

Microsoft Intune Cloud PKI

Microsoft Intune Cloud PKI and Certificate Templates

Microsoft Intune Cloud PKI and Active Directory

Microsoft Intune Cloud PKI and Certificate Templates

Microsoft recently announced the general availability of its new PKI-as-a-Service platform called Microsoft Intune Cloud PKI. With Intune Cloud PKI, administrators create certification authorities (CAs) to issue and manage user and device authentication certificates for Intune-managed endpoints. Cloud PKI also provides hosted Authority Information Access (AIA) and Certificate Revocation List (CRL) Distribution Point (CDP) services, in addition to Simple Certificate Enrollment Protocol (SCEP) service, so administrators do not have to deploy on-premises infrastructure to take advantage of certificate-based authentication.

Certificate Templates

After deploying your Intune Cloud PKI root and issuing CAs, you may wonder where to find the associated certificate templates. If you are familiar with traditional on-premises Active Directory Certificate Services (AD CS) implementations, this is how you define the purpose, key policy, security parameters, and lifetime of the certificate issued using that template. However, Intune Cloud PKI does not use certificate templates in the traditional way many administrators are familiar with.

Note: Microsoft may introduce support for certificate templates for Intune Cloud PKI in the future. However, it is not supported at the time of this writing.

SCEP Profile

Administrators define certificate policies and security parameters using Intune’s SCEP device configuration profile instead of certificate templates. In essence, the SCEP profile functions as the certificate template. With the Intune device configuration profile, administrators can define the following settings.

Certificate Type

The certificate type can be either a user or a device. Intune Cloud PKI can issue certificates for either or both, as required.

Subject Name (User)

The subject name is unimportant for user authentication certificates because the User Principal Name (UPN) defined in the Subject Alternative Name field is used to authenticate the user. In this field, the administrator can use whatever they like. However, it’s common to use the username here. Avoid using the email attribute here because there’s no guarantee that every user will have this defined on the Active Directory (AD) user object.

Subject Name (Device)

Administrators should supply the device’s fully qualified domain name (FQDN) for device authentication certificates in the subject name field. For hybrid Entra joined devices, administrators can use the {{FullyQualifiedDomainName}} variable. For native Entra-joined devices, you can use {{DeviceName}} and append your DNS suffix, for example, {{DeviceName}}.corp.example.net.

Note: Intune supports numerous variables to populate fields for certificates. You can find a list of supported variables in the following locations.

User Certificate Variables: https://learn.microsoft.com/en-us/mem/intune/protect/certificates-profile-scep#create-a-scep-certificate-profile:~:text=Manager%20blog%20post.-,User%20certificate%20type,-Use%20the%20text

Device Certificate Variables: https://learn.microsoft.com/en-us/mem/intune/protect/certificates-profile-scep#create-a-scep-certificate-profile:~:text=on%20the%20device.-,Device%20certificate%20type,-Format%20options%20for

Subject Alternative Name (User)

The Subject Alternative Name (SAN) field for user authentication certificates should be populated with the User Principal Name (UPN) value. Ensure this value is appropriately configured internally and supports sign-in to AD.

Subject Alternative Name (Device)

The SAN field for device authentication certificates should be populated with the device’s FQDN. Follow the guidance for device subject names covered previously.

Certificate Validity Period

This field allows the administrator to define the certificate’s validity period. The best practice is to limit the lifetime to no more than one year. A shorter lifetime is recommended for certificates not backed by a Trusted Platform Module (TPM).

Key Storage Provider

This value is critical to ensuring integrity for issued user and device authentication certificates. The best practice is to select Enroll to Trusted Platform Module (TPM) KSP, otherwise fail. However, if you must issue certificates to endpoints without a TPM (e.g., legacy devices, virtual machines, etc.), consider a separate profile with a shorter certificate lifetime to limit exposure.

Key Usage

Digital signature and Key encipherment are required for user and device authentication certificates.

Key Size

The 2048-bit key size is the minimum recommended value for certificates with RSA keys. Using 4096-bit is not recommended for end-entity certificates and can potentially cause conflicts in some cases. Intune Cloud PKI does not support the 1024-bit key size.

Hash Algorithm

SHA-2 is the best practice for the hash algorithm. SHA-1 has been deprecated and should not be used.

Root Certificate

Select the Cloud PKI root CA certificate.

Extended Key Usage

The minimum requirement for user and device authentication certificates is Client Authentication (1.3.6.1.5.5.7.3.2).

Renewal Threshold

This value specifies at what point the certificate can be renewed. 20% is commonly used for certificates with a one-year lifetime.

SCEP Server URLs

This value can be found on the configuration properties page of your Cloud PKI issuing CA. The URI will include a variable in the URL. The variable is there by design. Copy and paste this URL exactly as displayed in the SCEP URL field.

Training

Are you interested in learning more about issuing and managing certificates with Microsoft Intune? Would you like to know how to securely and optimally implement PKCS and SCEP infrastructure on-premises? Do you want more details about deploying and managing Microsoft Intune Cloud PKI? Register now for my upcoming three-day live Certificates and Intune Masterclass training event at the ViaMonstra online training academy. We’ll deep-dive into all aspects of certificate management using Intune with on-premises AD CS and Intune Cloud PKI. I’ll be sharing many advanced techniques for adequately securing your certificate infrastructure. Space is limited, so register now!

Additional Information

Mastering Certificates with Intune Training Course

Microsoft Intune Cloud PKI Overview

Microsoft Intune Cloud PKI and Active Directory

Microsoft Intune Certificate Connector Failure

Microsoft Intune Certificate Connector Configuration Failed

Microsoft Intune Certificate Connector Configuration Failure

Microsoft Intune Certificate Connector Service Account and PKCS