Tutorial: Grant and revoke app roles in Microsoft Entra ID

Artigo
03/05/2024

When you grant API permissions to a client app in Microsoft Entra ID, the permission grants are recorded as objects that can be accessed, updated, or deleted like other objects. Using Microsoft Graph PowerShell cmdlets to directly create permission grants is a programmatic alternative to interactive consent. This can be useful for automation scenarios, bulk management, or other custom operations in your organization.

Caution

Be Careful! Permissions created programmatically are not subject to review or confirmation. They take effect immediately.

In this tutorial, you'll grant app roles that are exposed by an API to an app. App roles, also called application permissions, or direct access permissions, allow an app to call an API with its own identity.

Prerequisites

To successfully complete this tutorial, make sure you have the required prerequisites:

A working Microsoft Entra tenant.
Microsoft Graph PowerShell SDK is installed. Follow the Install the Microsoft Graph PowerShell SDK guide to install the SDK.
Microsoft Graph PowerShell using a Privileged Role Administrator in the tenant and the appropriate permissions. For this tutorial, the Application.Read.All and AppRoleAssignment.ReadWrite.All delegated permissions are required. To set the permissions in Microsoft Graph PowerShell, run:
```
Connect-MgGraph -Scopes "Application.ReadWrite.All", "AppRoleAssignment.ReadWrite.All"
```

Caution

The AppRoleAssignment.ReadWrite.All permission allows an app or a service to manage permission grants and elevate privileges for any app, user, or group in your organization. Only appropriate users should access apps that have been granted this permission.

Step 1: Get the app roles of the resource service principal

Before you can grant app roles, you must first identify the app roles to grant and the resource service principal that exposes the app roles. App roles are defined in the appRoles object of a service principal.

In this article, you'll use the Microsoft Graph service principal in the tenant as your resource service principal.

Get-MgServicePrincipal -Filter "displayName eq 'Microsoft Graph'" -Property AppRoles | Select -ExpandProperty appRoles |fl

AllowedMemberTypes   : {Application}
Description          : Allows the app to read and update user profiles without a signed in user.
DisplayName          : Read and write all users' full profiles
Id                   : 741f803b-c850-494e-b5df-cde7c675a1ca
IsEnabled            : True
Origin               : Application
Value                : User.ReadWrite.All
AdditionalProperties : {}

AllowedMemberTypes   : {Application}
Description          : Allows the app to read user profiles without a signed in user.
DisplayName          : Read all users' full profiles
Id                   : df021288-bdef-4463-88db-98f22de89214
IsEnabled            : True
Origin               : Application
Value                : User.Read.All
AdditionalProperties : {}

Note

The output has been truncated for readability.

Step 2: Create a client service principal

The first step in granting consent is to create the service principal for the app that you'll grant permissions. To do so, you'll need the App Id of your application.

Register an application with Microsoft Entra ID

If the application isn't available, register an application with Microsoft Entra ID.

New-MgApplication -DisplayName 'My application' | 
  Format-List Id, DisplayName, AppId, SignInAudience, PublisherDomain

Id              : 40cbfad6-f138-4fb4-9e7f-5a44044efbd6
DisplayName     : My application
AppId           : 05210c44-437f-4a40-bd38-b5b4eaf251ef
SignInAudience  : AzureADandPersonalMicrosoftAccount
PublisherDomain : Contoso.com

Create a service principal for the application

New-MgServicePrincipal -AppId '05210c44-437f-4a40-bd38-b5b4eaf251ef' | 
  Format-List Id, DisplayName, AppId, SignInAudience

Id             : 22c1770d-30df-49e7-a763-f39d2ef9b369
DisplayName    : My application
AppId          : 05210c44-437f-4a40-bd38-b5b4eaf251ef
SignInAudience : AzureADandPersonalMicrosoftAccount

Step 3: Assign an app role to the client enterprise application

In this step, you'll assign an app role exposed by your resource app to the service principal we created in step 2. To create an app role assignment, you'll need the following information:

PrincipalId - object Id of the service principal to be authorized for direct access.
ResourceId - object Id of the service principal representing the resource app in your tenant.
AppRoleId - Id of the app role to be assigned, defined on the service principal representing the resource.

$params = @{
  "PrincipalId" ="22c1770d-30df-49e7-a763-f39d2ef9b369"
  "ResourceId" = "2cab1707-656d-40cc-8522-3178a184e03d"
  "AppRoleId" = "df021288-bdef-4463-88db-98f22de89214"
}

New-MgServicePrincipalAppRoleAssignment -ServicePrincipalId '2cab1707-656d-40cc-8522-3178a184e03d' -BodyParameter $params | 
  Format-List Id, AppRoleId, CreatedDateTime, PrincipalDisplayName, PrincipalId, PrincipalType, ResourceDisplayName

The ServicePrincipalId must always be same as the ResourceId, which references the service principal that exposes the app roles that you want to assign to the PrincipalId.

Id                   : DXfBIt8w50mnY_OdLvmzaUbMIDgaM6pCpU8rpQHnPf0
AppRoleId            : df021288-bdef-4463-88db-98f22de89214
CreatedDateTime      : 10/31/2022 11:00:47 AM
PrincipalDisplayName : My application
PrincipalId          : 22c1770d-30df-49e7-a763-f39d2ef9b369
PrincipalType        : ServicePrincipal
ResourceDisplayName  : Microsoft Graph

Step 4: Revoke an app role assignment from a client enterprise application

To revoke the app roles assigned in step 3, run:

Remove-MgServicePrincipalAppRoleAssignedTo -ServicePrincipalId '22c1770d-30df-49e7-a763-f39d2ef9b369' -AppRoleAssignmentId 'DXfBIt8w50mnY_OdLvmzaUbMIDgaM6pCpU8rpQHnPf0'

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