OAuth to secure iOS MDM enrolment process

Question

I have some MDM solution that we've developed through which we want to support managing iOS devices. Even though we'd already been able to successfully enrol and manage iOS devices via the same, I am trying to figure out a way to secure all web service invocations with OAuth, which take place between the native app running on iOS devices, connecting to the Enrolment and other APIs deployed as part of the MDM solution. Apparently, we've got limited control over modifying the native app to embed OAuth access tokens in the form of HTTP headers or some other means to be able to send those access tokens across to the MDM APIs, as the app logic cannot be modified. Do we have any configuration in the Enterprise App that runs on iOS devices to enable OAuth (or any other form of authentication) or some other means, which I can effectively use to get my requirement implemented?

Answer 1

iOS enrollment flow associate with a challenge token in the SCEP payload (mentioned as Challenge). Once you do the authentication from MDM server side there needs to be a unique token generated based on your user identity and embed that in this SCEP payload. For subsequent enrollment calls this token is passed and once the enrollment success this can be fetched and validate the user. Ideally this is just a way to link the device to a specific user which could be a temporary token generated at your MDM server end which link to a user identity or something related. To follow that you could apply OAuth password grant type and get the token once the authentication happens. Then this OAuth token can be then set as this challenge token for future use. But unlike in other OAuth communications iOS will not send this token in header as the bearer rather this will be embedded in the xml payload with proper encryption and signing in place.

Further iOS support protocol extension to validate users with open directory service using an auth token. This will by default have the ability to communicate back and forth using the checkin endpoint.