Hi Nat, please explain the attack. I assume the attacker would need to control network transmission or client device.
kind regards, Torsten. > Am 01.05.2016 um 07:36 schrieb Nat Sakimura <sakim...@gmail.com>: > > It actually depends on what risk level the transaction is at. For low risk > transactions, just having separate redirection endpoint may be adequate. On > the other hand, I can easily think of an attack that replaces iss on the > authz response making the control invalid posing questions on whether it is > worth introducing it. >> On Sun, May 1, 2016 at 14:21 Justin Richer <jric...@mit.edu> wrote: >> I agree that we’re getting dangerously close to recommending signed >> assertions at every step of the process, thereby bypassing HTTP. This was >> the same mistake that WS-* and SOAP made, let’s not repeat it if we can. >> >> — Justin >> >>> On Apr 30, 2016, at 10:57 AM, Torsten Lodderstedt <tors...@lodderstedt.net> >>> wrote: >>> >>> Hi Nat, >>> >>> sure, one could also authenticate and cryptographically protect the >>> redirect response. Leveraging OIDC concepts is an idea worth considering >>> but they should be adopted to the OAuth philosophy. The id token as used in >>> the hybrid flows mixes an identity assertion with elements of transport >>> security measures. A OAuth AS does not provide identity data to clients, so >>> we only need the transport security part. >>> I personally would prefer a OAuth response object (similar to request >>> object you have proposed) over the id token. Such a response object could >>> contain (and directly protect) state, code and other response values. I >>> consider this the more elegant design and it is easier to implement then >>> having detached signatures over hash values of codes or access tokens. >>> Moreover, it would allow to encrypt the response as well. >>> Generally, our threat analysis so far does not have provided justification >>> for cryptographically protected redirect responses. All proposals currently >>> on the table stop mix up and code injection using simpler mechanisms. >>> I think OAuth 2.0 is a huge success due to its balance of versatility, >>> security and _simplicity_. We definitely need to keep it secure, but we >>> should also keep it as simple as possible. >>> kind regards, >>> Torsten. >>>> Am 29.04.2016 um 10:08 schrieb Nat Sakimura: >>>> As I look at it more and more, it started to look like the problem of >>>> accepting tainted values without message authentication. To fix the root >>>> cause, we would have to authenticate response. ID Token was designed to >>>> also serve as a solution anticipating it. >>>> >>>> Any concrete ideas? >>>> >>>>> On Sat, Apr 23, 2016 at 04:47 Torsten Lodderstedt >>>>> <tors...@lodderstedt.net> wrote: >>>>> Hi all, >>>>> >>>>> discussion about Mix-Up and CnP seems to have stopped after the session >>>>> in BA - at least in the OAuth WG. There is a discussion about >>>>> mitigations in OpenId Connect going on at the OpenId Connect mailing list. >>>>> >>>>> I'm very much interested to find a solution within the OAuth realm as >>>>> I'm not interested to either implement two solutions (for OpenId Connect >>>>> and OAuth) or adopt a OpenId-specific solution to OAuth (use id! tokens >>>>> in the front channel). I therefore would like to see progress and >>>>> propose to continue the discussion regarding mitigations for both threats. >>>>> >>>>> https://tools.ietf.org/html/draft-ietf-oauth-mix-up-mitigation-00 >>>>> proposes reasonable mitigations for both attacks. There are alternatives >>>>> as well: >>>>> - mix up: >>>>> -- AS specific redirect uris >>>>> -- Meta data/turi >>>>> (https://tools.ietf.org/html/draft-sakimura-oauth-meta-07#section-5) >>>>> - CnP: >>>>> -- use of the nonce parameter (as a distinct mitigation beside state for >>>>> counter XSRF) >>>>> >>>>> Anyone having an opinion? >>>>> >>>>> best regards, >>>>> Torsten. >>>>> >>>>> _______________________________________________ >>>>> OAuth mailing list >>>>> OAuth@ietf.org >>>>> https://www.ietf.org/mailman/listinfo/oauth >>> >>> _______________________________________________ >>> OAuth mailing list >>> OAuth@ietf.org >>> https://www.ietf.org/mailman/listinfo/oauth
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