Microsoft Cloud PKI

This document describes the configuration steps necessary to implement certificate-based WiFi authentication using Microsoft Cloud PKI with Intune.

It is assumed that the Microsoft Cloud PKI hosts both the Root and Issuing CA. For scenarios involving BYOCAs please refer to Microsoft's online resources or the web.

Step 1: Deploy a Microsoft Cloud PKI

Create a Root CA in Intune admin center

Before you can issue certificates to managed devices, you need to create a root CA in your tenant to act as the trust anchor. To create a root CA in Intune admin center, please follow this Microsoft guide.

Please take note of the CRL distribution point as you will need this later in Step 2.

Create an Issuing CA in Intune admin center

An issuing CA is required to issue certificates for Intune-managed devices. Cloud PKI automatically provides a SCEP service that acts as a certificate registration authority. It requests certificates from the issuing CA on behalf of Intune-managed devices using a SCEP profile. To create an issuing CA, please follow this Microsoft guide.

Please take note of the CRL distribution point as you will need this later in Step 2.

Root and Issuing CAs

Step 2: Establish trust between RADIUSaaS and the Microsoft Cloud PKI

Configure RADIUSaaS to trust client authentication certificates issued by the Microsoft Cloud PKI. Since the cloud PKI requires a tiered CA structure, you must upload both, Root CA and Issuing CA (i.e. the complete chain of trust). To achieve this, please follow below steps:

1. Navigate to Trusted Certificates.

2. Upload the Contoso Cloud PKI Root CA selecting Client Authentication in the upload process.

3. As verification method select CRL along with DER encoding.

4. Use the copied CRL distribution point URL of the Root CA in the CRL Distribution Points URL input field.

5. Upload the Contoso Cloud PKI Issuing CA selecting Client Authentication in the upload process.

6. Again, select CRL as verification method along with DER encoding.

7. Use the copied CRL distribution point URL of the Issuing CA in the CRL Distribution Points URL input field.

Step 3: Configure the RADIUS Server Certificate

To establish server trust between your endpoint devices and RADIUSaaS, follow these instructions.

Step 4: Configure your networking equipment

To configure your networking equipment (WiFi access points, switches, or VPN gateways), follow these steps.

After successful completion of Steps 2 - 4, the Trusted Certificates page of your RADIUSaaS instance will look similar to the one below. Please note that in our example we have used a RadSec-enabled MikroTik access point.

Trusted Certificates Overview required for the Microsoft Cloud PKI.

Step 5: Configure Intune Profiles

To set up certificate-based WiFi authentication, we need to create a number of profiles and deploy them via Intune. These profiles are:

Profile Type	Purpose
Trusted certificate	Deploy the Root CA certificate.
Trusted certificate	Deploy the Issuing CA certificate.
Trusted certificate	Deploy the Root CA certificate that has issued the RADIUS Server Certificate.
SCEP certificate	Enroll the client authentication certificate.
Wi-Fi	Deploy the wireless network adapter settings.

Relevant Intune Profiles

Trusted certificate profiles

Microsoft Cloud PKI

Deploy the root CA and issuing CA certificates created in Step 1 via a Trusted certificate profile to your devices by navigating to the Intune admin center and then to Home > Devices > Windows > Configuration profiles > Create > New Policy with the following parameters:

• Platform = Windows 10 and later

• Profile type = Template

• Template name = Trusted certificate.

Upload the relevant certificate file (*.cer) in the respective profile:

• Root CA certificate created here

• Issuing CA certificate created here

Note that you have to use the same group for assigning the Trusted certificate and SCEP profiles. Otherwise, the Intune deployment might fail.

This must be repeated for every device platform that shall be using the service (e.g. Windows, macOS, ...)

RADIUS server trust

Next, push the root CA certificate that has issued your RADIUS Server Certificate as described here:

Server Trust

SCEP certificate profile

To create a SCEP certificate profile in Intune admin center, first take a copy of the SCEP URI from Home > Tenant admin > Cloud PKI > Contoso Issuing CA > Properties > SCEP URI.

Next, go to Home > Devices > Windows > Configuration profiles > Create > New Policy with the following parameters:

• Platform = Windows 10 and later

• Profile type = Template

• Template name = SCEP certificate

Next, configure the template according to the screenshot below making sure you attached the Contoso Root Certificate created earlier in step 1 and the SCEP URI you took a copy of above.

SCEP Device Certificate Configuration

This must be repeated for every device platform that shall be using the service (e.g. Windows, macOS, ...)

Wi-Fi profile

Deploy the WiFi adapter settings to your devices by following this article:

WiFi Profile