Azure OAuth2 Client Credential flow - getting token for multiple scopes throws error

Question

When using the MSAL library to generate access token for a background console application, using client_credentials, to call two REST endpoints, the get token call is created as:

client_id=XXX&client_info=1&client_secret=XXXX&scope=api%3A%2F%2FMyService-DevBlr-ClientServices%2F.default+api%3A%2F%2FMyService-DevBlr-CoreServices%2F.default&grant_type=client_credentials

and posted to

https://login.microsoftonline.com/a1326aec-378e-4433-8e2a-67a086554fc8/oauth2/v2.0/token

The response is a 400 error:

{"error":"invalid_scope","error_description":"AADSTS70011: The provided request must include a 'scope' input parameter. The provided value for the input parameter 'scope' is not valid. The scope api://MyService-DevBlr-ClientServices/.default api://MyService-DevBlr-CoreServices/.default is not valid.\r\nTrace ID: 203ad632-5e7c-4e61-9dcd-185eb9b49200\r\nCorrelation ID: 99fd979a-2c11-485b-ba14-c0cad3312e02\r\nTimestamp: 2020-01-11 08:36:29Z","error_codes":[70011],"timestamp":"2020-01-11 08:36:29Z","trace_id":"203ad632-5e7c-4e61-9dcd-185eb9b49200","correlation_id":"99fd979a-2c11-485b-ba14-c0cad3312e02"}

When individual scopes are passed in, the call works ok:

Request:
client_id=XXXX&client_info=1&client_secret=XXXX&scope=api%3A%2F%2FMyService-DevBlr-CoreServices%2F.default&grant_type=client_credentials 

Response:
{"token_type":"Bearer","expires_in":3599,"ext_expires_in":3599,"access_token":"eyJ0e..."}

and

Request: 
client_id=XXXX&client_info=1&client_secret=XXXX&scope=api%3A%2F%2FMyService-DevBlr-ClientServices%2F.default&grant_type=client_credentials

Response:
{"token_type":"Bearer","expires_in":3599,"ext_expires_in":3599,"access_token":"eyJ0eX..."}

The documentation and the API supports scopes array: https://github.com/AzureAD/microsoft-authentication-library-for-dotnet/wiki/Client-credential-flows#code-snippet

There is benefit in getting a single token to be used with multiple service calls, but I can't seem to get this working. Any suggestion is appreciated.

A token is generated for a specific audience. In your case, you need to call the function 2 times with different scopes each time and then use the tokens accordingly. — Prateek Kumar Dalbehera

juunas juunas · Accepted Answer · 2020-01-11T09:41:38

When you acquire an access token, you can only specify scopes for one API. It seems to me you are trying to acquire a token with permissions to 2 APIs. This is not possible.

An access token always only contains permissions to one API. So you must request them separately.

This is due to a token having an audience (aud) claim that identifies the API it is meant for. It cannot have two values.

Azure OAuth2 Client Credential flow - getting token for multiple scopes throws error

1 Answers