Identify admin permissions required by an Azure AD app registration - azure-active-directory

Question

How can I find out what admin permissions are blocking the user from signing in to an Azure AD app?
I am setting up an App Registration in the Azure AD portal to be used with my Service Fabric cluster. The app registration does basic auth and only has one Required Permission configured: Sign in and read user profile (which does NOT require admin permission).
My tenant has the "Users can consent to apps accessing company data on their behalf" setting to "Yes", so it's not that.
Also, the /authorize request doesn't have any resource parameter, so it's implicitly asking for the permission I configured: Azure AD's Sign in and read user profile.
However when an non-admin user attempts to sign it, I still get the error:
AADSTS90094: The grant requires admin permission

Answer 1

I reproduced the scenario and this is what I observed. Found a workaround, hope it helps.
First I created a Service Fabric (SF) cluster secured with AAD authentication using the steps described here, using an AAD tenant where I am not a global admin.
Then I tried to login to Service Fabric Explorer (SFX) and I got this error:
AADSTS50105: The signed in user is not assigned to a role for the
application 'f8c79129-deb7-4a21-a6e0-ec29e88298ef'
This is expected, because the user must be assigned to a role (Admin or ReadOnly) in the SF application that represents the cluster. So I went to AAD > Enterprise Applications > found my cluster app and under Users and Groups I added myself to the Admin role. Notice that the fact that a regular user can administer the roles of an application that the user owns is something new, it's available since a month or so -- before that, a regular user couldn't administer the roles of an application.
Then I tried to login again to SFX and I got a different error:
AADSTS65005: Invalid resource. The client has requested access to a
resource which is not listed in the requested permissions in the
client's application registration. Client app ID:
f8c79129-deb7-4a21-a6e0-ec29e88298ef. Resource value from request: .
Resource app ID: 00000002-0000-0000-c000-000000000000. List of valid
resources from app registration: .
00000002-0000-0000-c000-000000000000 is Windows Azure Active Directory. For some reason SetupApplications.ps1 doesn't assign the Sign in and Read User Profile permission to the SF cluster application. So I edited the application and I assigned that permission, just like you showed in your print screen. Notice that SetupApplications.ps1 has a parameter AddResourceAccess (not mentioned in the doc) that adds that permission, not sure why it doesn't add it by default. Perhaps it isn't needed when you run SetupApplications.ps1 as a global admin, and the scripts/doc assumes that you are a global admin.
Then I tried to login to SFX again and I got the same error that you observed:
AADSTS90094: The grant requires admin permission.
So I checked the SF application under AAD > Enterprise Applications > found the SF cluster app > Properties. User assignment required is configured "Yes". I changed it to "No" and tried to login to SFX. This time it worked OK, I could consent and access the SFX console. Then I changed User assignment required again to "Yes".
One can argue if the SF app really needs User assignment required > Yes because anyway if a user is not assigned to the Admin or ReadOnly role, SFX will try to fallback to client certificate authentication.
In either way, the AAD behavior is confusing. At least, the error should be more descriptive and point to the User assignment configuration. Perhaps the current behavior has to do with what I mentioned before, that regular users can now administer roles. Perhaps the behavior is being improved.