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

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

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) <[e-mail]> 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 <[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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