[keycloak-dev] why authenticate clients?

[Marek Posolda]

On 2.3.2014 23:24, Bill Burke wrote:
> A good read:
>
> http://tools.ietf.org/html/rfc6749#section-3.2.1
>
> I was thinking about our current client-secret requirement.  I don't
> think there is any security hole if you are doing the OAuth protocol
> over SSL, you are validating redirect_uris and the client sends its
> "client_id" when obtaining an access token.
>
> * Keycloak server ensures the access code is transmitted to a valid site
> by verifying/validating the redirect_uri sent.
I am not sure if protection based on redirect_uris could be considered 
secure. For example if Keycloak has application with redirect_uri 
"http://www.redhat.com/something" then nothing prevents me from adding 
"www.redhat.com" into my /etc/hosts and run application on my machine 
bind to "www.redhat.com", which will communicate with Keycloak. It seems 
that Keycloak won't be able to recognize if request really comes from 
valid "www.redhat.com" or from my fake host.

Marek
> * Since you're using HTTPS, the browser ensures the site is valid by
> checking it's cert.
> * If you send the "client_id" when obtaining the access token, the auth
> server can verify that there was no access code substitution.
>
> One of the uses described in 3.2.1 is that it is easier to reset a
> client's credentials than invalidating all the refresh tokens sent to
> it.  I'm not so sure that is true.  If there were a per-app/per-oauth
> client Not-Before setting, we could check this on a refresh request.
>
> Any counter arguments to these assumptions?  I'm going to see if anybody
> on the oauth email list will verify these assumptions.
>
>