I am doing some testing with the Webex SSO using OpenID Connect (OIDC), first for login only, in the "openid email" scope, and found some items which are not fully documented.
My questions the OIDC based SSO behavior of Webex:
- could you please confirm that the "JWKS endpoint" is really not used, and if yes, make this mandatory field optional?
- could you please confirm that the "User info endpoint" is really not used, and make this mandatory field optional?
- could you please confirm that the returned "access_token" within the OIDC token is not used, so may be empty?
- could you please confirm that the only the payload part of the returned "id_token" within the OIDC token is used, the other parts can be arbitrary values?
Or am I on a completely wrong path?
Background
In configuring the OIDC IdP details in Control Hub under "Manually add endpoint information", the CH requests mandatory URLs to the "JWKS endpoint" and "User info endpoint".
According to the IDC standard HERE, the JWKS endpoint is REQUIRED and returns key(s) to validate the id_token signature with. The User info endpoint is optional, and serves requests to user details.
In my understanding, the IDP should POST something similar to the Webex idbroker:
{
"token_type": "Bearer",
"expires_in": 3600,
"access_token": "...",
"scope": "email openid",
"id_token": "..."
}
and in my understanding the Webex side MUST verify the signature of the id_token using the key(s) downloaded from the "JWKS endpoint", and MAY ask for user details from the "User info endpoint".
However, at least in my tests, it looks like Webex does NOT verify the signature of the id_token, (does not even turn to the "JWKS endpoint" to get the verification key), and ignores the mandatory "iss" (issuer) param in the "id_token" JWT header. It does not turn to the "User info endpoint" either.
In spite of all these symptoms, the authentication is successful. I found no docs about the OIDC behavior of Webex, while the SAML behavior is quite well documented.
Thanks in advance for your clarification.
