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Microsoft Intune Cloud PKI

Recently, Microsoft introduced the general availability of its new PKI-as-a-service solution called Microsoft Intune Cloud PKI. Cloud PKI allows administrators to issue and manage user and device authentication certificates for Intune-managed endpoints without deploying Active Directory Certificate Services (AD CS) on-premises. Cloud PKI frees administrators from the burdens of deploying and managing AD CS, including the complicated Network Device Enrollment Service (NDES) server configuration required for Simple Certificate Enrollment Protocol (SCEP) certificate deployment with Intune.

Advantages

Microsoft Intune Cloud PKI offers many significant advantages over traditional on-premises AD CS deployments.

No Infrastructure

The most obvious advantage of using Cloud PKI is that you do not have to deploy and manage your own Certification Authority (CA). Although implementing AD CS isn’t that difficult, managing and operating a CA infrastructure securely can be quite challenging. In addition, a high-security AD CS deployment utilizes hardware secure modules (HSMs) to protect CA private keys, which are quite expensive and sometimes difficult to support.

Cloud-Hosted SCEP

Removing the requirement to configure and deploy your own NDES server to support SCEP certificates is certainly a welcome advantage. NDES is notoriously difficult to configure, secure, and troubleshoot when it doesn’t work correctly. Cloud PKI includes cloud hosted SCEP services that are highly available and redundant within the Microsoft Azure infrastructure.

Automatic Revocation

Cloud PKI automates the deployment of certificates to Intune-managed users and devices and automatically revokes certificates when they fall out of scope. Administrators can also manually revoke certificates using the Intune management console.

Reporting

Administrators can easily view the status of Cloud PKI-issued certificates in Intune. The UI shows the active, expired, and revoked certificates for the issuing CA.

Clicking View all certificates shows a detailed list of all certificates.

BYOCA

Another compelling feature of Cloud PKI is Bring Your Own CA (BYOCA). This feature enables administrators to deploy a cloud-hosted CA that is chained to their existing on-premises AD CS root CA. This is helpful for scenarios where AD CS is already in place and used to issue and manage certificates to existing domain-joined clients and servers. BYOCA effectively allows you to extend your existing CA infrastructure to the cloud and use Cloud PKI to issue and manage certificates for your Intune-managed endpoints while maintaining the full functionality and feature set of on-premises AD CS for non-Intune-managed devices.

Limitations

Although there are many advantages to Cloud PKI, there are some limiting factors to consider.

RSA Only

Today, Cloud PKI is limited to RSA keys only. Administrators can create CAs using RSA 2048, 3072, or 4096-bit keys. Elliptic Curve (EC) keys are not currently supported in Cloud PKI.

Intune Devices Only

Cloud PKI is limited to issuing certificates to Intune-managed devices only. Endpoints must be Entra-joined, or hybrid Entra-joined to enroll for certificates using Cloud PKI.

Inflexible Configuration

The Cloud PKI root and issuing CAs cannot be reconfigured after deployment. Since Cloud PKI root and issuing CAs don’t support the Any Purpose EKU (2.5.29.37.0), all EKUs must be defined when the CA is created. If, in the future, an administrator requires an EKU that was not present when the CA was deployed, an entirely new hierarchy (root and issuing CA) must be deployed.

Cost

There’s been much discussion about the cost associated with Cloud PKI. Cloud PKI can be licensed as part of the Intune Suite, which is $10.00 per user per month. Cloud PKI licenses will also be available as a standalone add-on for $2.00 per user per month. For large organizations, this might be cost-prohibitive.

Summary

Overall, Microsoft Intune Cloud PKI is a welcome addition to the Microsoft suite of cloud services. Certificates are excellent phishing-resistant credentials that can be used to improve security for organizations of all sizes. However, managing a CA can be tedious and time-consuming. Leveraging the cloud for PKI and certificate management will be helpful in many scenarios. However, Cloud PKI has some potential drawbacks, and many may not fit everyone.

More Information

Want to learn more about Microsoft Intune Cloud PKI and how it can benefit your organization? Take the first step towards streamlined certificate management and enhanced security for your organization. Fill out the form below, and I’ll provide more information about using Intune Cloud PKI to safeguard your digital assets confidently.

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6 Comments

by Richard M. Hicks on March 18, 2024 • Permalink

Posted in Active Directory, Active Directory Certificate Services, AD CS, administration, authentication, Azure, Azure Active Directory, Certificate Authentication, Certificate Authority, Certificate Connector for Intune, Certificate Services, certificates, cloud, Cloud PKI, Cloud Service, Cryptography, Device Management, Encryption, Endpoint Manager, Enterprise, enterprise mobility, Entra, Entra ID, HAADJ, Hybrid Azure AD Join, Infrastructure, Intune, Intune Certificate Connector, Intune PFX Connector, MDM, Microsoft, Microsoft Endpoint Manager, Microsoft Entra, Microsoft Entra ID, Microsoft Intune, Mobile Device Management, Mobility, Multifactor Authentiction, Network Device Enrollment Service, Network Device Enrollment Services, network policy server, NPS, Operational Support, PFX Connector, PKCS, PKI, public cloud, public key infrastructure, SCEP, Security, Simple Certificate Enrollment Protocol, systems management, TPM, troubleshooting, Windows 10, Windows 11

Posted by Richard M. Hicks on March 18, 2024

https://directaccess.richardhicks.com/2024/03/18/microsoft-intune-cloud-pki/

Microsoft Intune Cloud PKI and Active Directory

Recently, Microsoft introduced a new PKI-as-a-Service offering called Cloud PKI. This cloud-based PKI can issue and manage certificates to Intune-managed endpoints. Administrators can now deploy user and device authentication certificates using Intune Cloud PKI without deploying Active Directory Certificate Services (AD CS) on-premises. Numerous blog posts and YouTube videos show how to configure and deploy Intune Cloud PKI, so I won’t reinvent the wheel with a complete configuration guide here. This article will focus instead on integrating Microsoft Intune Cloud PKI with on-premises Active Directory (AD).

Note: Administrators must deploy certificates to all enterprise domain controllers and RADIUS servers to support certificate-based authentication with AD. However, Cloud PKI for Intune can only issue certificates to Intune-managed endpoints today. It cannot issue certificates to servers. Administrators must use another CA (AD CS or another Cloud PKI solution) to issue and manage domain controller and RADIUS server certificates on-premises to support this scenario.

AD Integration

While Intune Cloud PKI eliminates the need for on-premises AD CS infrastructure, there will be times when Cloud PKI-issued certificates will be used to authenticate to on-premises AD, either through a RADIUS server such as Windows Network Policy Server (NPS), which is common for VPN and Wi-Fi deployments, or other methods. Additional configuration is required to support this scenario.

Publish Root/Issuing CA Certificates

The Intune Cloud PKI root and issuing CA certificates must be published in AD to support on-premises AD authentication using Intune Cloud PKI-issued certificates. Follow the steps below to complete this task.

Note: Arguably, you could skip publishing the Intune Cloud PKI root and issuing CA certificates in on-premises AD because Cloud-PKI certificates can only be issued to Intune-managed endpoints, in which case you are likely already deploying the Cloud PKI root and issuing CA certificates using Intune. I’m including these steps for completeness. However, publishing the Intune Cloud PKI issuing CA certificate in the NtAuthCA certificate store in AD is required to support on-premises AD authentication using Intune Cloud PKI-issued certificates, so that step is mandatory.

RootCA Store

On a domain-joined computer on-premises, open an elevated PowerShell or command window and run the following command to publish the Intune Cloud PKI root CA certificate to the RootCA certificate store in AD.

certutil.exe -dspublish -f <path to Cloud PKI root CA certificate> RootCA

SubCA Store

Next, run the following command to publish the Cloud PKI issuing CA certificate to the SubCA certificate store in AD.

certutil.exe -dspublish -f <path to Cloud PKI issuing CA certificate> SubCA

NtAuthCA Store

Finally, run the following command to publish the Intune Cloud PKI issuing CA certificate to the NtAuthCA certificate store in AD. Publishing the Intune Cloud PKI issuing CA certificate in the NtAuthCA store in AD allows certificates issued by Intune Cloud PKI to be used to authenticate on-premises AD if required. Be sure to run this command even if you did not run the previous commands to publish the Intune Cloud PKI root and issuing CA certificates in AD.

certutil.exe -dspublish -f <path to Cloud PKI issuing CA certificate> NtAuthCa

GUI

If you have an existing on-premises AD CS deployment, you can use the Enterprise PKI management console to publish the Intune Cloud PKI certificates in AD as an alternative to the command line. First, open the Enterprise PKI tool (pkiview.msc) on an existing on-premises Certification Authority (CA) server. Right-click the Enterprise PKI root node and choose Manage AD Containers. Add the Intune Cloud PKI root CA certificate to the Certification Authorities container. Next, add the Intune Cloud PKI issuing CA certificate to the Enrollment Services container. Finally, add the Intune Cloud PKI issuing CA certificate to the NTAuthCertificatesContainer.

Summary

Administrators can use the Microsoft Intune Cloud PKI solution to issue and manage user and device authentication certificates for their Intune-managed endpoints. Using the commands above, administrators can also integrate their Intune Cloud PKI with on-premises Active Directory to support user and device authentication for common workloads such as Wi-Fi and VPN. Critically, when integrating Cloud PKI with on-premises Active Directory, your Intune administrators should be considered Tier-0 administrators, and appropriate security controls should be enforced.

Additional Information

Microsoft Intune Cloud PKI

Mastering Certificates with Microsoft Intune Training Course – May 14-16, 2024

10 Comments

by Richard M. Hicks on March 5, 2024 • Permalink

Tagged Active Directory, AD, AD CS, authentication, CA, certificate, certificates, Certification Authority, Cloud PKI, InTune, Intune Cloud PKI, issuing CA, MDM, MEM, NDES, NPS, PKCS, PKI, PKI-as-a-Service, RADIUS, root CA, SCEP, WIFI

Posted by Richard M. Hicks on March 5, 2024

https://directaccess.richardhicks.com/2024/03/05/microsoft-intune-cloud-pki-and-active-directory/

Always On VPN Static IP Address Assignment

A question that occasionally arises when I’m conducting an Always On VPN planning and design workshop for a customer is static IP address assignment options for VPN connections. Typically, the use case is a specific user that requires special access to a sensitive system internally. Assigning a static IP address to the user allows administrators to create firewall rules restricting access to this connection.

Static IP Assignment

Assigning a static IP address to a user is accomplished by editing the properties of their user account in Active Directory. Open the Active Directory Users and Computers console (dsa.msc), navigate to the Dial-in tab on the target individual’s Active Directory user account, and check the box next to Assign Static IP Addresses.

Next, click the Static IP Addresses button, check the box next to Assign a Static IPv4 address, and enter an IP address. Optionally, check the box next to Assign a static IPv6 address and enter a prefix and Interface ID, if required.

NPS Configuration

Once the user account in Active Directory is configured with a static IP address assignment, each NPS server in the organization must be registered in Active Directory. More details on Active Directory registration for NPS servers can be found here.

Caveats

Assigning static IP addresses to VPN users has many drawbacks and limitations. Consider the following.

Device IP

Assigning a static IP address to a device is not supported. You can only assign a static IP address to a user in Active Directory.

Address Assignment

The IP address you assign to the user must be from the same subnet as the VPN server’s internal network interface. If there is more than one VPN server, all VPN servers must be on the same subnet.

Multisite

Assigning static IP addresses to users is not supported when VPN servers are deployed in multiple locations.

Concurrent Sessions

Users with a static IP address assignment must only log on to one device at a time. If a user attempts to log in to multiple devices simultaneously, subsequent connections will fail due to the duplicate IP address assignment.

NPS

Always On VPN administrators may have discovered the option to assign a static IP address using NPS policy. Unfortunately, this option is severely limited. A separate NPS policy is needed for each user that requires a static IP address. However, NPS does not support assigning NPS policies to users, only groups. Technically speaking, you could create a separate group for each user needing a static IP address, but that’s not scalable. Also, it offers no real advantage over using the Active Directory method described above.

Summary

Although it’s possible to assign a static IP address to a user, there is currently no option to assign a static IP address to a device. In addition, static IP address assignment imposes other limitations that make the option challenging. Also, the inability to connect to geographically dispersed VPN servers is severely limiting.