Microsoft Entra app registrations serve as the foundation for establishing identity and authentication for applications within the Microsoft Entra ID (formerly Azure Active Directory) ecosystem. When you register an application, you create an identity configuration that enables your app to integrat…Microsoft Entra app registrations serve as the foundation for establishing identity and authentication for applications within the Microsoft Entra ID (formerly Azure Active Directory) ecosystem. When you register an application, you create an identity configuration that enables your app to integrate with Microsoft's identity platform for authentication and authorization purposes.
An app registration creates two related objects: an application object and a service principal. The application object serves as a global template defining the app's properties, while the service principal represents the local instance in a specific tenant, controlling what the app can actually do within that directory.
Key components of app registrations include:
**Application (Client) ID**: A unique identifier assigned to your application, used during authentication flows to identify which app is requesting access.
**Redirect URIs**: URLs where Microsoft Entra ID sends authentication responses after users sign in or grant consent.
**Certificates and Secrets**: Credentials that applications use to authenticate themselves when requesting tokens. Certificates are recommended for production environments due to enhanced security.
**API Permissions**: Define what resources and scopes your application can access. These can be delegated permissions (acting on behalf of users) or application permissions (acting as the app itself).
**Exposed APIs**: Allow your application to define its own scopes that other applications can request access to.
From a security perspective, app registrations require careful management. Security engineers should implement least privilege principles when assigning permissions, regularly audit registered applications, monitor for unused or orphaned registrations, and ensure proper credential rotation policies are in place.
App registrations support various authentication scenarios including single-page applications, web apps, mobile apps, daemon services, and APIs. Understanding these registrations is essential for implementing secure identity solutions and controlling how applications interact with organizational resources and user data within your Azure environment.
Microsoft Entra App Registrations: Complete Guide for AZ-500
Why Microsoft Entra App Registrations Are Important
Microsoft Entra app registrations are fundamental to securing applications in Azure. They provide the identity framework that allows applications to authenticate users, access protected resources, and integrate with Microsoft 365 and Azure services securely. For security engineers, understanding app registrations is critical because misconfigurations can lead to unauthorized access, data breaches, and privilege escalation attacks.
What Are Microsoft Entra App Registrations?
An app registration is an identity configuration for your application within Microsoft Entra ID (formerly Azure Active Directory). When you register an application, you create a trust relationship between your app and the Microsoft identity platform. This registration generates:
• Application (client) ID - A unique identifier for your application • Directory (tenant) ID - Identifies which Entra ID tenant the app belongs to • Client secrets or certificates - Credentials the app uses to prove its identity • Redirect URIs - URLs where authentication responses are sent
How App Registrations Work
The app registration process involves several key components:
1. Authentication Configuration You define how users and services authenticate to your application. This includes setting supported account types (single tenant, multi-tenant, or personal Microsoft accounts) and configuring redirect URIs for OAuth 2.0 flows.
2. API Permissions App registrations define what resources the application can access. Permissions fall into two categories: • Delegated permissions - Used when a signed-in user is present; the app acts on behalf of the user • Application permissions - Used for background services or daemons; the app acts as itself
3. Expose an API If your application provides APIs for other applications to consume, you configure scopes and authorized client applications here.
4. Certificates and Secrets Applications use credentials to authenticate. Certificates are more secure than client secrets and are recommended for production environments. Secrets have expiration dates and must be rotated regularly.
5. Enterprise Applications vs App Registrations App registrations define the application identity, while enterprise applications (service principals) represent the instance of the app in a specific tenant and control user access and permissions.
Security Best Practices
• Always use certificates over client secrets when possible • Apply the principle of least privilege when assigning API permissions • Require admin consent for sensitive permissions • Regularly audit app registrations and remove unused applications • Configure appropriate token lifetimes • Use managed identities for Azure resources when applicable • Enable conditional access policies for enterprise applications
Exam Tips: Answering Questions on Microsoft Entra App Registrations
Understand Permission Types Questions often test whether you know the difference between delegated and application permissions. Remember that delegated permissions require a user context, while application permissions are used by services running in the background.
Know When Admin Consent Is Required High-privilege permissions like reading all users' profiles or accessing mailboxes require administrator consent. Standard users cannot grant these permissions themselves.
Certificate vs Secret Questions When exam questions ask about the most secure authentication method for applications, certificates are preferred over client secrets. Secrets should have short expiration periods.
Multi-Tenant Scenarios Pay attention to questions about multi-tenant applications. These apps can authenticate users from any Entra ID tenant and require careful permission configuration.
Managed Identity Priority If a question presents options that include managed identities for Azure-to-Azure authentication, this is typically the correct answer as it eliminates credential management.
Service Principal Relationships Remember that creating an app registration automatically creates a service principal in the home tenant. For multi-tenant apps, service principals are created in each tenant where the app is used.
Common Exam Scenarios • Configuring an app to access Microsoft Graph API • Setting up authentication for a web application • Troubleshooting permission and consent issues • Securing daemon applications that run unattended • Implementing proper credential management and rotation