In the previous posts I’ve discussed authenticating and authorizing a user with Azure Active Directory (Azure AD) using a basic application registration. All application registrations are given default permissions to access the Azure Graph API – this was used in my previous post to retrieve information about the signed in user. The default permission set is a delegated permission that allows the user to sign in and view their own profile. This can be viewed in the Azure portal by extending the Required permissions tab for the application.
In this post I’m going to extend this permission set to include the “Read directory data” permission. You’ll notice in the previous image that there is a green tick in the “Requires Admin” column. What this means is that in order for a regular user (ie a user that is not a global administrator for the tenant) to sign in, a global administrator must first sign in and consent to permission on behalf of the organisation. If a regular user attempts to sign in, they’ll be confronted with an error message such as:
Essentially the error “AADSTS90093: Calling principal cannot consent due to lack of permissions” indicates that a global administrator needs to sign in an consent on behalf of the organisation before users can sign in. When a global administrator does sign in, they’ll be prompted to consent for those their permissions, but also permissions on behalf of the organisation.
After the global administrator has consented, user’s will still be prompted to consent but this is for the delegated permission. In the same way that user permissions can be revoked by going to https://myapps.microsoft.com and deleting the application entry, organisation permissions can be revoked by opening the Enterprise applications tab for the Active Directory in the Azure portal. Select the application you want to remove and click the Delete button.
After the global administrator has consented for the organisation, any user can then read the directory data (ie more than just their own profile).