Re: [OAUTH-WG] Call for Adoption: OAuth 2.0 Mix-Up Mitigation

["Phil Hunt (IDM)" <[e-mail]>]

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 <[e-mail]> 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 <[e-mail]> 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 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 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
>> [e-mail]
>> 
>> 
>> 
>> 
>> 
>>> On Jan 25, 2016, at 4:52 PM, nov matake <[e-mail]> 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 <[e-mail]> wrote:
>>>> 
>>>> Sorry, meant to reply-all.
>>>> 
>>>> Phil
>>>> 
>>>> @independentid
>>>> www.independentid.com
>>>> [e-mail]
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>>> Begin forwarded message:
>>>>> 
>>>>> From: Phil Hunt <[e-mail]>
>>>>> 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 <[e-mail]>
>>>>> 
>>>>> 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
>>>>> [e-mail]
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>>> On Jan 25, 2016, at 2:58 PM, Nat Sakimura <[e-mail]> 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) <[e-mail]>:
>>>>>>> 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 <[e-mail]> wrote:
>>>>>>> >
>>>>>>> > would
>>>>>>> 
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