Hi all, Besides the state leakage attack we found that another important fact regarding state is underspecified: Each state value should only be used for one run of the protocol, in particular, each AS should see a different state in multi-AS settings. Clients might be tempted to generate state once and then re-use each time a user wants to authorize.
If state is re-used, given a setup where one Client allows users to authorize using two AS, a potentially malicious AS learns the state value that is valid for authorization at an honest AS. I.e., each AS can mount a CSRF attack on the user using the other AS. Just as the attack in the other mail, this is not a big deal in practice, but should be discussed somewhere. Cheers, Daniel, Guido, and Ralf -- Informationssicherheit und Kryptografie Universität Trier - Tel. 0651 201 2847 - H436 _______________________________________________ OAuth mailing list OAuth@ietf.org https://www.ietf.org/mailman/listinfo/oauth
