In this flow, AuthZ endpoint is forced to be TLS-protected. http://nat.sakimura.org/wp-content/uploads/2016/01/oauth-idp-mixup.png
However, RP’s redirect response which causes following AuthZ request is still not TLS-protected, and modified on the attacker’s proxy. Section 3.2 of this report also describes the same flow. http://arxiv.org/pdf/1601.01229v2.pdf > On Jan 26, 2016, at 12:37, Phil Hunt (IDM) <phil.h...@oracle.com> wrote: > > Also the authz endpoint is required to force tls. So if the client doesn't do > it the authz should reject (eg by upgrading to tls). > > Phil > > On Jan 25, 2016, at 19:29, Phil Hunt (IDM) <phil.h...@oracle.com > <mailto:phil.h...@oracle.com>> wrote: > >> When the RP acting as the client issues a authorize redirect to the UA it >> has to make it with TLS >> >> Phil >> >> On Jan 25, 2016, at 17:53, Nov Matake <mat...@gmail.com >> <mailto:mat...@gmail.com>> wrote: >> >>> It doen't say anything about the first request which initiate the login >>> flow. >>> It is still a reasonable assumption that RP puts a "login with FB" button >>> on a non TLS-protected page. >>> >>> nov >>> >>> On Jan 26, 2016, at 10:45, Phil Hunt <phil.h...@oracle.com >>> <mailto:phil.h...@oracle.com>> wrote: >>> >>>> I would find it hard to believe that is true. >>>> >>>> From 6749 Sec 3.1 >>>> Since requests to the authorization endpoint result in user >>>> authentication and the transmission of clear-text credentials (in the >>>> HTTP response), the authorization server MUST require the use of TLS >>>> as described in Section 1.6 >>>> <https://tools.ietf.org/html/rfc6749#section-1.6> when sending requests to >>>> the >>>> authorization endpoint. >>>> >>>> Sec 3.1.2.1 >>>> The redirection endpoint SHOULD require the use of TLS as described >>>> in Section 1.6 <https://tools.ietf.org/html/rfc6749#section-1.6> when >>>> the requested response type is "code" or "token", >>>> or when the redirection request will result in the transmission of >>>> sensitive credentials over an open network. This specification does >>>> not mandate the use of TLS because at the time of this writing, >>>> requiring clients to deploy TLS is a significant hurdle for many >>>> client developers. If TLS is not available, the authorization server >>>> SHOULD warn the resource owner about the insecure endpoint prior to >>>> redirection (e.g., display a message during the authorization >>>> request). >>>> >>>> Lack of transport-layer security can have a severe impact on the >>>> security of the client and the protected resources it is authorized >>>> to access. The use of transport-layer security is particularly >>>> critical when the authorization process is used as a form of >>>> delegated end-user authentication by the client (e.g., third-party >>>> sign-in service). >>>> >>>> Section 10.5 talks about transmission of authorization codes in connection >>>> with redirects. >>>> >>>> Also see 6819, Sec 4.4.1.1 regarding eavesdropping or leaking of authz >>>> codes. >>>> >>>> >>>> Phil >>>> >>>> @independentid >>>> www.independentid.com <http://www.independentid.com/>phil.h...@oracle.com >>>> <mailto:phil.h...@oracle.com> >>>> >>>> >>>> >>>> >>>> >>>>> On Jan 25, 2016, at 4:52 PM, nov matake <mat...@gmail.com >>>>> <mailto:mat...@gmail.com>> wrote: >>>>> >>>>> The first assumption is coming from the original security report at >>>>> http://arxiv.org/abs/1601.01229 <http://arxiv.org/abs/1601.01229>. >>>>> RFC 6749 requires TLS between RS and AS, and also between UA and AS, but >>>>> not between UA and RS. >>>>> >>>>> The blog post is based on my Japanese post, and it describes multi-AS >>>>> case. >>>>> Nat's another post describes the case which can affect single-AS case too. >>>>> http://nat.sakimura.org/2016/01/22/code-phishing-attack-on-oauth-2-0-rfc6749/ >>>>> >>>>> <http://nat.sakimura.org/2016/01/22/code-phishing-attack-on-oauth-2-0-rfc6749/> >>>>> >>>>> nov >>>>> >>>>>> On Jan 26, 2016, at 08:22, Phil Hunt <phil.h...@oracle.com >>>>>> <mailto:phil.h...@oracle.com>> wrote: >>>>>> >>>>>> Sorry, meant to reply-all. >>>>>> >>>>>> Phil >>>>>> >>>>>> @independentid >>>>>> www.independentid.com >>>>>> <http://www.independentid.com/>phil.h...@oracle.com >>>>>> <mailto:phil.h...@oracle.com> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> Begin forwarded message: >>>>>>> >>>>>>> From: Phil Hunt <phil.h...@oracle.com <mailto:phil.h...@oracle.com>> >>>>>>> Subject: Re: [OAUTH-WG] Call for Adoption: OAuth 2.0 Mix-Up Mitigation >>>>>>> Date: January 25, 2016 at 3:20:19 PM PST >>>>>>> To: Nat Sakimura <sakim...@gmail.com <mailto:sakim...@gmail.com>> >>>>>>> >>>>>>> I am having trouble with the very first assumption. The user-agent sets >>>>>>> up a non TLS protected connection to the RP? That’s a fundamental >>>>>>> violation of 6749. >>>>>>> >>>>>>> Also, the second statement says the RP (assuming it acts as OAuth >>>>>>> client) is talking to two IDPs. That’s still a multi-AS case is it not? >>>>>>> >>>>>>> Phil >>>>>>> >>>>>>> @independentid >>>>>>> www.independentid.com >>>>>>> <http://www.independentid.com/>phil.h...@oracle.com >>>>>>> <mailto:phil.h...@oracle.com> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>>> On Jan 25, 2016, at 2:58 PM, Nat Sakimura <sakim...@gmail.com >>>>>>>> <mailto:sakim...@gmail.com>> wrote: >>>>>>>> >>>>>>>> Hi Phil, >>>>>>>> >>>>>>>> Since I was not in Darmstadt, I really do not know what was discussed >>>>>>>> there, but with the compromised developer documentation described in >>>>>>>> http://nat.sakimura.org/2016/01/15/idp-mix-up-attack-on-oauth-rfc6749/ >>>>>>>> <http://nat.sakimura.org/2016/01/15/idp-mix-up-attack-on-oauth-rfc6749/>, >>>>>>>> all RFC6749 clients with a naive implementer will be affected. The >>>>>>>> client does not need to be talking to multiple IdPs. >>>>>>>> >>>>>>>> Nat >>>>>>>> >>>>>>>> 2016年1月26日(火) 3:58 Phil Hunt (IDM) <phil.h...@oracle.com >>>>>>>> <mailto:phil.h...@oracle.com>>: >>>>>>>> I recall making this point in Germany. 99% of existing use is fine. >>>>>>>> OIDC is probably the largest community that *might* have an issue. >>>>>>>> >>>>>>>> I recall proposing a new security document that covers oauth security >>>>>>>> for dynamic scenarios. "Dynamic" being broadly defined to mean: >>>>>>>> * clients who have configured at runtime or install time (including >>>>>>>> clients that do discovery) >>>>>>>> * clients that communicate with more than one endpoint >>>>>>>> * clients that are deployed in large volume and may update frequently >>>>>>>> (more discussion of "public" cases) >>>>>>>> * clients that are script based (loaded into browser on the fly) >>>>>>>> * others? >>>>>>>> >>>>>>>> Phil >>>>>>>> >>>>>>>> > On Jan 25, 2016, at 10:39, George Fletcher <gffle...@aol.com >>>>>>>> > <mailto:gffle...@aol.com>> wrote: >>>>>>>> > >>>>>>>> > would >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> OAuth mailing list >>>>>>>> OAuth@ietf.org <mailto:OAuth@ietf.org> >>>>>>>> https://www.ietf.org/mailman/listinfo/oauth >>>>>>>> <https://www.ietf.org/mailman/listinfo/oauth> >>>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> OAuth mailing list >>>>>> OAuth@ietf.org <mailto:OAuth@ietf.org> >>>>>> https://www.ietf.org/mailman/listinfo/oauth >>>>>> <https://www.ietf.org/mailman/listinfo/oauth> >>>>> >>>> >> _______________________________________________ >> OAuth mailing list >> OAuth@ietf.org <mailto:OAuth@ietf.org> >> https://www.ietf.org/mailman/listinfo/oauth >> <https://www.ietf.org/mailman/listinfo/oauth>
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