Does OAuth security vulnerability affect OpenID/OAuth hybrid?

[Luke Shepard]

(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:


 1.  Request a request token by pretending to request access
 2.  Force the user to go to a url using that request token
 3.  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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