Does OAuth security vulnerability affect OpenID/OAuth hybrid?

[Allen Tom]

At the very least, the security considerations section should say that 
the OP should have obtained the user's consent to authorize the Access 
Token before issuing it to the RP. This means that the Access Token 
should not be returned via checkid_immediate unless the user had 
approved the token on a previous checkid_setup request.

There are federation scenarios (ie: close partnerships, etc) where user 
consent might not be necessary, so obtaining the user's consent is a 
SHOULD (or STRONGLY RECOMMENDED) rather than a MUST.

Allen


Breno de Medeiros wrote:
> I can see some federation scenarios where admins might want to
> configure auto-approvals for specific set of scopes for some set of
> users (essentially OpenID as a single sign-on mechanism with data
> transport). Putting this restriction directly into the standard as a
> MUST or SHOULD would mean that libraries would likely enforce checks
> (maybe without a configuration option) and make such deployments hard.
>
> Maybe we should have a security considerations sections?
>
> On Wed, May 13, 2009 at 5:05 PM, Andrew Arnott <andrewarnott at gmail.com> wrote:
>   
>> I would expect a decent OP to consider that it goes without saying that
>> checkid_immediate wouldn't have a reasonable OAuth token authorizing
>> scenario and block it.  So I agree it's good to call it out in the spec.
>> --
>> Andrew Arnott
>> "I [may] not agree with what you have to say, but I'll defend to the death
>> your right to say it." - S. G. Tallentyre
>>
>>
>> On Tue, May 12, 2009 at 10:06 PM, Allen Tom <atom at yahoo-inc.com> wrote:
>>     
>>> Hi Luke,
>>>
>>> I don't think there's a session fixation issue with Hybrid, but I believe
>>> that several individuals raised concerns regarding auto-approval of OAuth
>>> tokens using regular OAuth, which is essentially the same thing as
>>> checkid_immediate mode in Hybrid.
>>>
>>> Is there really a reason why an RP would need the OAuth token returned in
>>> a checkid_immediate response if the user had previously authorized one on an
>>> earlier visit?
>>>
>>> Allen
>>>
>>>
>>> Luke Shepard wrote:
>>>
>>> (hijacking thread a bit)
>>>
>>> Allen-
>>>
>>> If I understand it correctly, the OAuth security issue doesn’t affect the
>>> hybrid spec in the same way.
>>>
>>> With the OAuth session fixation vulnerability, the problem comes if the
>>> attacker does the following:
>>>
>>> Request a request token by pretending to request access
>>> Force the user to go to a url using that request token
>>> Muah! Calculate what the return_to url would have been, and use the
>>> pre-known request token to gain access to the user’s account info.
>>>
>>> In the OAuth hybrid flow, there is no pre-registered request token;
>>> instead, the token is returned, securely, in the URL. It is protected by the
>>> fact that OpenID requires the realm to match the return_to, and many
>>> providers can require that the Oauth request realm also match the OpenID
>>> realm. In this flow, there’s no way for the attacker to intercept the
>>> request_token before it makes its way back to the correct user.
>>>
>>> Perhaps the problem is more subtle than I understood, but I just want  to
>>> make sure I’m clear on the issues.
>>>
>>> On 5/12/09 9:48 PM, "Allen Tom" <atom at yahoo-inc.com> wrote:
>>>
>>> Hi Nat,
>>>
>>> Here you go:
>>>
>>>
>>> http://step2.googlecode.com/svn/spec/openid_oauth_extension/latest/openid_oauth_extension.html
>>>
>>> We might need to revise the spec to not support checkid_immediate for
>>> the Hybrid flow, becuase auto-issuing OAuth access tokens is probably a
>>> bad thing, in light of the recent OAuth security issue.
>>>
>>> Allen
>>>
>>>
>>>
>>>
>>>
>>> Nat Sakimura wrote:
>>>       
>>>> Hi.
>>>>
>>>> Where can I find the most current version of OpenID / OAuth hybrid spec
>>>> draft?
>>>> I would like to look at it to see if I can borrow as much from the
>>>> draft for what I am thinking right now.
>>>>
>>>>
>>>>         
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