keycloak token introspection always fails with {"active":false}

Question

I'm kind of desesperate to make this keycloak work. I can authenticate but for some reason, my token introspection always fail. For example if I try to authenticate:

curl -d 'client_id=flask_api' -d 'client_secret=98594477-af85-48d8-9d95-f3aa954e5492' -d '[email protected]' -d 'password=superpassE0' -d 'grant_type=password' 'http://keycloak.dev.local:9000/auth/realms/skilltrock/protocol/openid-connect/token'

I get my access_token as expected:

{
   "access_token":"eyJhbGciOiJSUzI1NiIsInR5cCIgOiAiSldUIiwia2lkIiA6ICJnLVZJQ0VETnJ4NWRfN1pWQllCTC1tNDdTZWFNT3NDVlowSFdtZF9QQkZrIn0.eyJqdGkiOiIwNTBkYWI5MS1kMjA5LTQwYjctOTBkOS1mYTgzMWYyMTk1Y2MiLCJleHAiOjE1NDQ1MjIyNDEsIm5iZiI6MCwiaWF0IjoxNTQ0NTIxOTQxLCJpc3MiOiJodHRwOi8va2V5Y2xvYWsuZGV2LmxvY2FsOjkwMDAvYXV0aC9yZWFsbXMvc2tpbGx0cm9jayIsImF1ZCI6ImFjY291bnQiLCJzdWIiOiI3NDA0MWNkNS1lZDBhLTQzMmYtYTU3OC0wYzhhMTIxZTdmZTAiLCJ0eXAiOiJCZWFyZXIiLCJhenAiOiJmbGFza19hcGkiLCJhdXRoX3RpbWUiOjAsInNlc3Npb25fc3RhdGUiOiJiOGI0MzA2Ny1lNzllLTQxZmItYmNkYi0xMThiMTU2OWU3ZDEiLCJhY3IiOiIxIiwicmVhbG1fYWNjZXNzIjp7InJvbGVzIjpbIm9mZmxpbmVfYWNjZXNzIiwidW1hX2F1dGhvcml6YXRpb24iXX0sInJlc291cmNlX2FjY2VzcyI6eyJhY2NvdW50Ijp7InJvbGVzIjpbIm1hbmFnZS1hY2NvdW50IiwibWFuYWdlLWFjY291bnQtbGlua3MiLCJ2aWV3LXByb2ZpbGUiXX19LCJzY29wZSI6ImVtYWlsIHByb2ZpbGUiLCJlbWFpbF92ZXJpZmllZCI6ZmFsc2UsIm5hbWUiOiJqZWFuIHBpZXJyZSIsInByZWZlcnJlZF91c2VybmFtZSI6ImplYW5AZ21haWwuY29tIiwiZ2l2ZW5fbmFtZSI6ImplYW4iLCJmYW1pbHlfbmFtZSI6InBpZXJyZSIsImVtYWlsIjoiamVhbkBnbWFpbC5jb20ifQ.x1jW1cTSWSXN5DsXT3zk1ra4-BcxgjXbbqV5cjdwKTovoNQn7LG0Y_kR8-8Pe8MvFe7UNmqrHbHh21wgZy1JJFYSnnPKhzQaiT5YTcXCRybSdgXAjnvLpBjVQGVbMse_obzjjE1yTdROrZOdf9ARBx6EBr3teH1bHMu32a5wDf-fpYYmHskpW-YoQZljzNyL353K3bmWMlWSGzXx1y7p8_T_1WLwPMPr6XJdeZ5kW0hwLcaJVyDhX_92CFSHZaHQvI8P095D4BKLrI8iJaulnhsb4WqnkUyjOvDJBqrGxPvVqJxC4C1NXKA4ahk35tk5Pz8uS33HY6BkcRKw7z6xuA",
   "expires_in":300,
   "refresh_expires_in":1800,
   "refresh_token":"eyJhbGciOiJIUzI1NiIsInR5cCIgOiAiSldUIiwia2lkIiA6ICJlYmY4ZDVlOC01MTM4LTRiNTUtYmZhNC02YzcwMzBkMTIwM2YifQ.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.omhube2oe79dXlcChOD9AFRdUep53kKPjD0HF14QioY",
   "token_type":"bearer",
   "not-before-policy":0,
   "session_state":"b8b43067-e79e-41fb-bcdb-118b1569e7d1",
   "scope":"email profile"
}

But if I try to introspect the access_token like given below, keycloack return always {"active":false}. I really don't understand this behavior.

curl -X POST -u "flask_api:98594477-af85-48d8-9d95-f3aa954e5492" -d "token=eyJhbGciOiJSUzI1NiIsInR5cCIgOiAiSldUIiwia2lkIiA6ICJnLVZJQ0VETnJ4NWRfN1pWQllCTC1tNDdTZWFNT3NDVlowSFdtZF9QQkZrIn0.eyJqdGkiOiIwNTBkYWI5MS1kMjA5LTQwYjctOTBkOS1mYTgzMWYyMTk1Y2MiLCJleHAiOjE1NDQ1MjIyNDEsIm5iZiI6MCwiaWF0IjoxNTQ0NTIxOTQxLCJpc3MiOiJodHRwOi8va2V5Y2xvYWsuZGV2LmxvY2FsOjkwMDAvYXV0aC9yZWFsbXMvc2tpbGx0cm9jayIsImF1ZCI6ImFjY291bnQiLCJzdWIiOiI3NDA0MWNkNS1lZDBhLTQzMmYtYTU3OC0wYzhhMTIxZTdmZTAiLCJ0eXAiOiJCZWFyZXIiLCJhenAiOiJmbGFza19hcGkiLCJhdXRoX3RpbWUiOjAsInNlc3Npb25fc3RhdGUiOiJiOGI0MzA2Ny1lNzllLTQxZmItYmNkYi0xMThiMTU2OWU3ZDEiLCJhY3IiOiIxIiwicmVhbG1fYWNjZXNzIjp7InJvbGVzIjpbIm9mZmxpbmVfYWNjZXNzIiwidW1hX2F1dGhvcml6YXRpb24iXX0sInJlc291cmNlX2FjY2VzcyI6eyJhY2NvdW50Ijp7InJvbGVzIjpbIm1hbmFnZS1hY2NvdW50IiwibWFuYWdlLWFjY291bnQtbGlua3MiLCJ2aWV3LXByb2ZpbGUiXX19LCJzY29wZSI6ImVtYWlsIHByb2ZpbGUiLCJlbWFpbF92ZXJpZmllZCI6ZmFsc2UsIm5hbWUiOiJqZWFuIHBpZXJyZSIsInByZWZlcnJlZF91c2VybmFtZSI6ImplYW5AZ21haWwuY29tIiwiZ2l2ZW5fbmFtZSI6ImplYW4iLCJmYW1pbHlfbmFtZSI6InBpZXJyZSIsImVtYWlsIjoiamVhbkBnbWFpbC5jb20ifQ.x1jW1cTSWSXN5DsXT3zk1ra4-BcxgjXbbqV5cjdwKTovoNQn7LG0Y_kR8-8Pe8MvFe7UNmqrHbHh21wgZy1JJFYSnnPKhzQaiT5YTcXCRybSdgXAjnvLpBjVQGVbMse_obzjjE1yTdROrZOdf9ARBx6EBr3teH1bHMu32a5wDf-fpYYmHskpW-YoQZljzNyL353K3bmWMlWSGzXx1y7p8_T_1WLwPMPr6XJdeZ5kW0hwLcaJVyDhX_92CFSHZaHQvI8P095D4BKLrI8iJaulnhsb4WqnkUyjOvDJBqrGxPvVqJxC4C1NXKA4ahk35tk5Pz8uS33HY6BkcRKw7z6xuA" http://localhost:9000/auth/realms/skilltrock/protocol/openid-connect/token/introspect

return

{"active":false}

Where I am wrong? I'm totally lost

Answer 1

You need to make sure that you introspect the token using the same DNS hostname/port as the request. Unfortunately that's a not widely documented "feature" of Keycloak... So use:

   curl -u "flask_api:98594477-af85-48d8-9d95-f3aa954e5492" -d "token=<token>" http://keycloak.dev.local:9000/auth/realms/skilltrock/protocol/openid-connect/token/introspect

Answer 2

A legacy alternative is to send a Host header with the introspection request which matches the frontend host where the token was obtained. That I have tried, I can confirm that it works. It requires configuration of two URLs for the introspecting protected resource, though.

Since Keycloak 8 it is also possible to use the OpenID Connect Discovery as described in https://issues.redhat.com/browse/KEYCLOAK-11728 and the attached design document.

The latter solution involves two things:

1. Keycloak needs to know the frontend URL used for token retrieval by clients; that can happen at start time as described in the server installation (-Dkeycloak.frontendUrl or standalone.xml) or when definining a realm through its Frontend URL Option in the Keycloak Management UI. The Keycloak docker container supports the environment variable KEYCLOAK_FRONTEND_URL for this. Note that the frontendUrl needs to include the basePath where Keycloak is running (/auth by default, adjust as needed).
2. Optionally, the protected resource can use OIDC discovery to determine the introspection URL. Either use the Keycloak Java Adapter >=v8 which has built-in support for OIDC Discovery or verify if your protected resource does. See the related PR on the Keycloak Java Adapter for details.

When a protected resource uses the internal discovery endpoint http://keycloak:8998/auth/realms/myrealm/.well-known/openid-configuration, it will find the correct internal introspection endpoint:

{
  "issuer": "http://localhost:8998/auth/realms/myrealm",
  "authorization_endpoint": "http://localhost:8998/auth/realms/myrealm/protocol/openid-connect/auth",
  "token_endpoint": "http://keycloak:8080/auth/realms/myrealm/protocol/openid-connect/token",
  "token_introspection_endpoint": "http://keycloak:8080/auth/realms/myrealm/protocol/openid-connect/token/introspect"
}

Using the discovery endpoint is not required. If you just need to introspect an incoming token with Keycloak, you can directly use the introspection endpoint.

Answer 3

The introspect endpoint can also return {"active":false} if a session associated with that token doesn't exist in Keycloak. For example, if you create the token, restart keycloak and then call introspect.