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Example of API protected by Microsoft identity consent framework

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This article can help you, as a developer, to design your application permissions strategy to provide least privilege. Before proceeding, see the API protection article to learn best practices for registration, permissions, and access.

Let's take a look at how an API that is protected by the Microsoft identity platform uses the Microsoft identity consent framework. We use the Microsoft Graph API as our example because it makes the most extensive use of the Microsoft identity platform consent framework.

Naming convention for permission names

The Microsoft Graph team created a naming convention for permission names to make it easier to connect the permission to the resource access that the permission enables. Microsoft Graph permission names adhere to a simple resource.operation.constraint pattern. The two primary operations are Read and ReadWrite (which includes update and delete).

The constraint element affects the degree of access that your app has within the directory. Microsoft Graph supports these constraints:

  • All grants permission for your app to perform the operations on all of the resources of the specified type in a directory.
  • Shared grants permission for your app to perform the operations on resources that other users shared with the signed-in user.
  • AppFolder grants permission for your app to read and write files in a dedicated folder in OneDrive. This constraint is exposed only on the Files permissions object and is only valid for Microsoft accounts.
  • If you specify No constraint, your app can only perform the operations on the resources that the signed-in user owns.

Access and operations against specific resources

Let's look at some permissions, or scopes, for the user object in Microsoft Graph to see how the Microsoft API designers enabled specific access and operations against specific resources:

Permission Display String Description
User.Read Sign-in and read user profile Allows users to sign-in to the app and allows the app to read the profile of signed-in users. It also allows the app to read basic company information of signed-in users.
User.ReadWrite Read and write access to user profile Allows the app to read the signed-in user's full profile. It also allows the app to update the signed-in user's profile information on their behalf.

User.Read and User.ReadWrite exist (as opposed to a single permission like User.Access that doesn't exist) so that applications can follow the Zero Trust principle of least privilege. If the developer doesn't have a requirement and code to update the user's profile, the app doesn't ask for User.ReadWrite. Therefore, an attacker can't compromise the application and use it to change data.

Notice that User.Read doesn't just give the application access to the user object. Each permission represents a specific range of operation. It's important that developers and admins read the permission description to see exactly what any specific permission enables. User.Read, in addition to enabling reading the current user's full profile, enables the application to see the basic information from the Organizations object in Microsoft Graph.

Let's look at another permission:

Permission Display String Description
User.ReadBasic.All Read all users' basic profiles Allows the app to read a basic set of profile properties of other users in your organization on behalf of the signed-in user. Includes display name, first and family name, email address, open extensions, and photo. Allows the app to read the full profile of the signed-in user.

The range of operation that User.ReadBasic.All starts with everything that User.Read does. In addition, you can access display name, first and family name, email address, photo, and open extensions for other organization users. The specific range of operation enables applications to have a nice people picker UI and is an example of the API designers using a permission to enable a specific range of operation.

Let's look at a couple more permissions on the Microsoft Graph user object:

Permission Display String Description
User.Read.All Read all users' full profiles Allows the app to read the full set of profile properties, reports, and managers of other users in your organization, on behalf of the signed-in user.
User.ReadWrite.All Read and write all users' full profiles Allows the app to read and write the full set of profile properties, reports, and managers of other users in your organization, on behalf of the signed-in user. Also allows the app to create and delete users and reset user passwords on behalf of the signed-in user.

As with User.Read and User.ReadWrite, User.Read.All and User.ReadWrite.All are distinct permissions that enable an application to follow the least privilege Zero Trust principle.

User.Read.All is interesting because every user in the organization has this capability (for example, open Outlook, go up and down a reporting chain). You, as an individual, can see the full user profile of every other user in your organization. However, the Microsoft Graph API designers decided that only admins should allow an application to perform the same operation because User.Read.All includes the tenant's organizational hierarchy. If a bad actor accessed this information, they could mount a targeted phishing attack where the phishing email came from a person's manager or their manager's manager.

User.ReadWrite.All is a powerful range of operation. An application granted this permission can update, or even delete, every user in the tenant. As a delegated permission, when a user is in front of the app, the app can do only what the current user can do. Regular users can't update or delete other users regardless of the app's permissions. However, when a tenant admin uses the app, then they can perform these operations. When deciding to grant or deny this permission, you should evaluate your app with a tenant admin user in mind.

Given the power of User.Read.All and User.ReadWrite.All, the Microsoft Graph API designers designated these permissions as requiring admin consent. Let's add an Admin? Column to our table of permissions to indicate when the permission requires admin consent:

Permission Display String Description Admin?
User.Read Sign-in and read user profile Allows users to sign-in to the app and allows the app to read the profile of signed-in users. It also allows the app to read basic company information of signed-in users. No
User.ReadWrite Read and write access to user profile Allows the app to read the signed-in user's full profile. It also allows the app to update the signed-in user's profile information on their behalf. No
User.ReadBasic.All Read all users' basic profiles Allows the app to read a basic set of profile properties of other users in your organization on behalf of the signed-in user. Includes display name, first and family name, email address, open extensions, and photo. Allows the app to read the full profile of the signed-in user. No
User.Read.All Read all users' full profiles Allows the app to read the full set of profile properties, reports, and managers of other users in your organization, on behalf of the signed-in user. Yes
User.ReadWrite.All Read and write all users' full profiles Allows the app to read and write the full set of profile properties, reports, and managers of other users in your organization, on behalf of the signed-in user. Also allows the app to create and delete users and reset user passwords on behalf of the signed-in user. Yes

As demonstrated in the Request permissions that require administrative consent article, tenant admins can overrule requirements and designate any or all application permissions in their tenant as requiring admin consent. You're wise to design your app to gracefully handle when you don't receive a token from your request. Lack of consent is one of many reasons that your app might not receive a token.

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