Microsoft Graph is the gateway to data and intelligence in Microsoft 365. To interact with this data securely and effectively, understanding its permission model is crucial. This post dives into the core concepts of Microsoft Graph permissions, helping you navigate the different types and choose the right ones for your applications.
What are Microsoft Graph Permissions?
Microsoft Graph permissions are scopes that an application requests to access specific resources and perform actions on behalf of a user or an organization. They act as granular controls, ensuring that applications only get the access they absolutely need. This principle, known as the principle of least privilege, is fundamental to modern security practices.
Types of Permissions
Microsoft Graph permissions are broadly categorized into two main types:
1. Delegated Permissions
Delegated permissions are used by applications that act on behalf of a signed-in user. The application's permissions are restricted by the permissions of the signed-in user. For example, if a user can read their own calendar, an application delegated calendar.Read permission can only read that user's calendar, not anyone else's.
User.Read: Allows the application to read the profile of the signed-in user.Mail.Read: Allows the application to read the signed-in user's mail.Files.ReadWrite.All: Allows the application to read and write all files that the signed-in user can access.
2. Application Permissions
Application permissions are used by background services or daemons that do not have a signed-in user. These permissions allow the application to act as itself, with no user context. This means the application can access data across the entire organization, subject to its granted permissions. These are often more powerful and require administrator consent.
Directory.Read.All: Allows the application to read data in your organization's directory.User.ReadWrite.All: Allows the application to read and write all users' full profiles.SecurityEvents.Read.All: Allows the application to read all security events.
Key Distinction: Delegated permissions are limited by the user's scope, while application permissions operate at the organizational level, requiring higher trust and often administrator intervention.
Permission Levels: Read vs. ReadWrite and Other Scopes
Within each permission type, you'll often see variations indicating the level of access:
- Read: Allows viewing of resources (e.g.,
User.Read,Calendar.Read). - ReadWrite: Allows viewing and modifying resources (e.g.,
User.ReadWrite,Tasks.ReadWrite). .All: Denotes that the permission applies to all resources of that type within the scope (user or organization). For example,Files.Read.Allgrants read access to all files the user can access, not just a specific set..Selected: (Less common, but exists for some resources) Indicates permission to access specific resources rather than all..All.Shared: (Specific to certain resources like Tasks) Allows access to all tasks shared with the user or organization.
Admin Consent vs. User Consent
Permissions can be categorized by who grants consent:
- User Consent: For many lower-impact delegated permissions (like
User.Read), users can consent directly when prompted by the application. - Admin Consent: For higher-impact delegated permissions (like
Mail.Send.All) and all application permissions, an administrator must grant consent for the organization. This is typically done through the Azure portal or by using the Azure AD admin consent endpoint.
Common Permission Scenarios
Here's a quick look at some typical permission needs:
| Scenario | Permission Type | Microsoft Graph Permission | Notes |
|---|---|---|---|
| App reads signed-in user's basic profile | Delegated | User.Read |
User consent |
| App sends emails on behalf of the user | Delegated | Mail.Send |
User consent (or admin for .All) |
| App reads all users in the directory | Application | User.Read.All |
Admin consent required |
| App manages groups (create, update, delete) | Application | Group.ReadWrite.All |
Admin consent required |
| App reads calendar events for all users | Application | Calendars.Read.All |
Admin consent required |
| App reads a specific user's files in OneDrive | Delegated | Files.Read |
User consent |
Best Practices for Permissions
- Request only necessary permissions: Adhere strictly to the principle of least privilege.
- Use delegated permissions when possible: If your app has a user context, delegated permissions are generally safer and easier to manage.
- Clearly inform users: Explain why your application needs specific permissions.
- Handle consent gracefully: Guide users through the consent process and provide alternatives if consent is denied.
- Regularly review permissions: Especially for applications with application permissions, periodic audits are crucial.
Mastering Microsoft Graph permissions is key to building secure, reliable, and user-friendly applications that leverage the power of the Microsoft 365 ecosystem. Always refer to the official Microsoft Graph permissions reference for the most up-to-date and comprehensive information.