Yup. For the RPs that would deal with valuable data, I also recommend it to become HTTPS only. This will effectively close the hole for the AS Mix-Up. Also, I would recommend to the clients to think twice before accepting random ASs. To prevent the code phishing, it is a good idea to require the same authority restriction. Otherwise, use some variant of discovery to get the authoritative token endpoints.
2016年1月27日(水) 21:49 George Fletcher <gffle...@aol.com>: > Based on Hans' response to Nat I understand why this doesn't solve all the > use cases. It does still seem like a good idea from a client perspective > that would address the dynamic client registration cases where the Bad AS > is returning mixed endpoints. > > > On 1/27/16 7:43 AM, George Fletcher wrote: > > Following up on Nat's last paragraph... did the group in Darmstadt discuss > this option? Namely, to require that the authority section of the AuthZ and > Token endpoints be the same? Are there known implementations already > deployed where the authority sections are different? It seems like a simple > check that would address the endpoint mix-up cases. > > Thanks, > George > > On 1/26/16 8:58 PM, Nat Sakimura wrote: > > John, > > Nov is not talking about the redirection endpoint. I just noticed that > 3.1.2.1 of RFC 6749 is just asking TLS by "SHOULD" and I think it needs to > be changed to "MUST" but that is not what he is talking about. > > Instead, he is talking about before starting the RFC 6749 flow. > > In many cases, a non TLS protected sites have "Login with HIdP" button > linked to a URI that initiates the RFC 6749 flow. This portion is not > within RFC 6749 and this endpoint has no name or no requirement to be TLS > protected. Right, it is very stupid, but there are many sites like that. > As a result, the attacker can insert itself as a proxy, say by providing a > free wifi hotspot, and either re-write the button or the request so that > the RP receives "Login with AIdP" instead of "Login with HIdP". > > I have add a note explaining this to > http://nat.sakimura.org/2016/01/15/idp-mix-up-attack-on-oauth-rfc6749/ > > I also have added a bit of risk analysis on it and considered other risk > control measures as well. > > It does not seem to be worthwhile to introduce a new wire-protocol element > to deal with this particular attack. (I regard code cut-and-paste attack a > separate attack.) I am inclining to think that just to TLS protect the > pre-RFC6749 flow portion and add a check to disallow the ASs that has > different authority section for the Auhtz EP and Token EP would be > adequate. > > Nat > > 2016年1月27日(水) 2:18 John Bradley <ve7...@ve7jtb.com>: > >> Nov, >> >> Are you referring to Sec 3.1.2.1 of RFC 6749. >> >> Stating that the the redirection endpoint SHOULD require TLS, and that >> the AS should warn the user if the redirect URI is not over TLS (Something >> I have never seen done in the real world) >> >> Not using TLS is reasonable when the redirect URI is using a custom >> scheme for native apps. >> >> It might almost be reasonable for the token flow where the JS page itself >> is not loaded over TLS so the callback to extract the fragment would not be >> as well. >> Note that the token itself is never passed over a non https connection in >> tis case. >> I would argue now that it is irresponsible to have a non TLS protected >> site, but not everyone is going to go along with that. >> >> Using a http scheme URI for the redirect is allowed but is really stupid. >> We did have a large debate about this when profiling OAuth for Connect. >> We did tighten connect to say that if you are using the code flow then a >> http scheme redirect URI is only allowed if the client is confidential. >> >> John B. >> >> On Jan 26, 2016, at 1:14 AM, Phil Hunt (IDM) <phil.h...@oracle.com> >> wrote: >> >> Still don't see it. Though i think the diagram is wrong (the rp should >> redirct to the ua and not call the authz direct), the IDP should either >> return an error or redirect the RP to TLS. >> >> I don't see this as proper oauth protocol since the RP is MITM the UA >> rather than acting as a client. >> >> Phil >> >> On Jan 25, 2016, at 19:57, nov matake <mat...@gmail.com> wrote: >> >> 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> 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> 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> 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 >> phil.h...@oracle.com >> >> >> >> >> >> On Jan 25, 2016, at 4:52 PM, nov matake <mat...@gmail.com> wrote: >> >> The first assumption is coming from the original security report at >> 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/ >> >> nov >> >> On Jan 26, 2016, at 08:22, Phil Hunt <phil.h...@oracle.com> wrote: >> >> Sorry, meant to reply-all. >> >> Phil >> >> @independentid >> www.independentid.com >> phil.h...@oracle.com >> >> >> >> >> >> Begin forwarded message: >> >> *From: *Phil Hunt <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> >> >> 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 >> phil.h...@oracle.com >> >> >> >> >> >> On Jan 25, 2016, at 2:58 PM, Nat Sakimura <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/, >> 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>: >> >>> 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> wrote: >>> > >>> > would >>> >>> _______________________________________________ >>> 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 >> >> >> >> _______________________________________________ >> 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 >> >> >> _______________________________________________ >> OAuth mailing list >> OAuth@ietf.org >> https://www.ietf.org/mailman/listinfo/oauth >> > > > _______________________________________________ > OAuth mailing listOAuth@ietf.orghttps://www.ietf.org/mailman/listinfo/oauth > > > -- > Chief Architect > Identity Services Engineering Work: george.fletc...@teamaol.com > AOL Inc. AIM: gffletch > Mobile: +1-703-462-3494 Twitter: http://twitter.com/gffletch > Office: +1-703-265-2544 Photos: http://georgefletcher.photography > > > > _______________________________________________ > OAuth mailing listOAuth@ietf.orghttps://www.ietf.org/mailman/listinfo/oauth > > > -- > Chief Architect > Identity Services Engineering Work: george.fletc...@teamaol.com > AOL Inc. AIM: gffletch > Mobile: +1-703-462-3494 Twitter: http://twitter.com/gffletch > Office: +1-703-265-2544 Photos: http://georgefletcher.photography > >
_______________________________________________ OAuth mailing list OAuth@ietf.org https://www.ietf.org/mailman/listinfo/oauth
