Add partner certification authority in Intune using SCEP
In Microsoft Intune, third-party certification authorities (CA) can be added. These CAs can deliver certificates to mobile devices using the Simple Certificate Enrollment Protocol (SCEP). This feature can issue new certificates and renew certificates on Windows, iOS, Android, and macOS devices.
There are two parts to using this feature: open-source API, and the Intune administrator tasks.
Part 1 - Use an open-source API
Microsoft created an API that integrates with Intune to validate certificates, send success or failure notifications, and use SSL, specifically SSL socket factory, to communicate with Intune.
The API is available on the Intune SCEP API public GitHub repository for you to download, and use in your solutions. Use this API with third-party SCEP servers to run custom challenge validation against Intune before delivering a certificate to a device.
Integrate with Intune SCEP management solution provides more details on using the API, its methods, and testing the solution you build.
Part 2 - Create the application and profile
Using an Azure Active Directory (Azure AD) application, you can delegate rights to Intune to handle SCEP requests coming from devices. The Azure AD application includes application ID and authentication key values that are used within the API solution the developer creates. Administrators can then create and deploy SCEP certificates profiles using Intune. You can also view reports on the deployment status on the devices.
This article provides an overview of this feature from an Administrator-perspective, including creating the Azure AD application.
The following steps provide an overview of issuing SCEP certificates in Intune:
- In Intune, an administrator creates a SCEP certificate profile, and then targets the profile to users or devices.
- The device checks in to Intune.
- Intune creates a unique SCEP challenge. It also adds additional integrity-check information, such as what the expected subject and SAN should be.
- Intune encrypts and signs both the challenge and integrity-check information, and then sends this information to the device with the SCEP request.
- The device generates a certificate signing request (CSR) and public/private key pair on the device based on the SCEP certificate profile that's pushed from Intune.
- The CSR and encrypted/signed challenge are sent to the third-party SCEP server endpoint.
- The SCEP server sends the CSR and the challenge to Intune. Intune then validates the signature, decrypts the payload, and compares the CSR to the integrity-check information.
- Intune sends back a response to the SCEP server, and states whether the challenge validation is successful or not.
- If the challenge is successfully verified, then the SCEP server issues the certificate to the device.
The following diagram shows a detailed flow of third-party SCEP integration with Intune:
Set up third-party CA integration
Validate third-party certification authority
Before integrating third-party certification authorities with Intune, confirm that the CA you're using supports Intune. Third-party CA partners (in this article) includes a list. You can also check your certification authority's guidance for more information. The CA may include setup instructions specific to their implementation.
Authorize communication between CA and Intune
To allow a third-party SCEP server to run custom challenge validation with Intune, create an app in Azure AD. This app gives delegated rights to Intune to validate SCEP requests.
Be sure you have the required permissions to register an Azure AD app. See Required permissions, in the Azure AD documentation.
Create an application in Azure Active Directory
In the Azure portal, go to Azure Active Directory > App Registrations, and then select New registration.
On the Register an application page, specify the following details:
- In the Name section, enter a meaningful application name.
- For the Supported account types section, select Accounts in any organizational directory.
- For Redirect URI, leave the default of Web, and then specify the sign-on URL for the third-party SCEP server.
Select Register to create the application and to open the Overview page for the new app.
On the app Overview page, copy the Application (client) ID value and record it for later use. You'll need this value later.
In the navigation pane for the app, go to Certificates & secrets under Manage. Select the New client secret button. Enter a value in Description, select any option for Expires, and then and choose Add to generate a value for the client secret.
Before you leave this page, copy the value for the client secret and record it for later use with your third-party CA implementation. This value is not shown again. Be sure to review the guidance for your third-party CA on how they want the Application ID, Authentication Key, and Tenant ID configured.
Record your Tenant ID. The Tenant ID is the domain text after the @ sign in your account. For example, if your account is *firstname.lastname@example.org*, then your tenant ID is name.onmicrosoft.com.
In the navigation pane for the app, go to API permissions under Manage, and then select Add a permission.
On the Request API permissions page, select Intune, and then select Application permissions. Select the checkbox for scep_challenge_provider (SCEP challenge validation).
Select Add permissions to save this configuration.
Remain on the API permissions page, and select Grant admin consent for Microsoft, and then select Yes.
The app registration process in Azure AD is complete.
Configure and deploy a SCEP certificate profile
As the administrator, create a SCEP certificate profile to target to users or devices. Then, assign the profile.
When you unenroll or wipe the device, the certificates are removed. The certificates aren't revoked.
Third-party certification authority partners
The following third-party certification authorities support Intune:
If you're a third-party CA interested in integrating your product with Intune, review the API guidance:
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