Re: [OAUTH-WG] Mix-Up and CnP/ Code injection

Hi Torsten,

No, not defeating, but being able to find out if the input is tainted or
not.

Nat
On Mon, May 9, 2016 at 07:46 <torsten@lodderstedt.net> wrote:

> Are you suggesting OAuth should defeat maleware? So far, this was
> considered to be handled by OS/Anti-Virus/other measures.
>
>
> -------- Originalnachricht --------
> Betreff: Re: [OAUTH-WG] Mix-Up and CnP/ Code injection
> Von: Nat Sakimura <sakimura@gmail.com>
> An: Torsten Lodderstedt <torsten@lodderstedt.net>
> Cc: Justin Richer <jricher@mit.edu>,"<oauth@ietf.org>" <oauth@ietf.org>
>
> Yes, and unfortunately, that is a rather common attack these days.
> Infesting a user device with a malware is probably easier than having the
> client developer register its client to unknown server.
>
> 2016年5月1日(日) 16:54 Torsten Lodderstedt <torsten@lodderstedt.net>:
>
>> Hi Nat,
>>
>> please explain the attack. I assume the attacker would need to control
>> network transmission or client device.
>>
>> kind regards,
>> Torsten.
>>
>> Am 01.05.2016 um 07:36 schrieb Nat Sakimura <sakimura@gmail.com>:
>>
>> It actually depends on what risk level the transaction is at. For low
>> risk transactions, just having separate redirection endpoint may be
>> adequate. On the other hand, I can easily think of an attack that replaces
>> iss on the authz response making the control invalid posing questions on
>> whether it is worth introducing it.
>> On Sun, May 1, 2016 at 14:21 Justin Richer <jricher@mit.edu> wrote:
>>
>>> I agree that we’re getting dangerously close to recommending signed
>>> assertions at every step of the process, thereby bypassing HTTP. This was
>>> the same mistake that WS-* and SOAP made, let’s not repeat it if we can.
>>>
>>>  — Justin
>>>
>>> On Apr 30, 2016, at 10:57 AM, Torsten Lodderstedt <
>>> torsten@lodderstedt.net> wrote:
>>>
>>> Hi Nat,
>>>
>>> sure, one could also authenticate and cryptographically protect the
>>> redirect response. Leveraging OIDC concepts is an idea worth considering
>>> but they should be adopted to the OAuth philosophy. The id token as used in
>>> the hybrid flows mixes an identity assertion with elements of transport
>>> security measures. A OAuth AS does not provide identity data to clients, so
>>> we only need the transport security part.
>>>
>>> I personally would prefer a OAuth response object (similar to request
>>> object you have proposed) over the id token. Such a response object could
>>> contain (and directly protect) state, code and other response values. I
>>> consider this the more elegant design and it is easier to implement then
>>> having detached signatures over hash values of codes or access tokens.
>>> Moreover, it would allow to encrypt the response as well.
>>>
>>> Generally, our threat analysis so far does not have provided
>>> justification for cryptographically protected redirect responses. All
>>> proposals currently on the table stop mix up and code injection using
>>> simpler mechanisms.
>>>
>>> I think OAuth 2.0 is a huge success due to its balance of versatility,
>>> security and _simplicity_. We definitely need to keep it secure, but we
>>> should also keep it as simple as possible.
>>>
>>> kind regards,
>>> Torsten.
>>> Am 29.04.2016 um 10:08 schrieb Nat Sakimura:
>>>
>>> As I look at it more and more, it started to look like the problem of
>>> accepting tainted values without message authentication. To fix the root
>>> cause, we would have to authenticate response. ID Token was designed to
>>> also serve as a solution anticipating it.
>>>
>>> Any concrete ideas?
>>>
>>> On Sat, Apr 23, 2016 at 04:47 Torsten Lodderstedt <
>>> torsten@lodderstedt.net> wrote:
>>>
>>>> Hi all,
>>>>
>>>> discussion about Mix-Up and CnP seems to have stopped after the session
>>>> in BA - at least in the OAuth WG. There is a discussion about
>>>> mitigations in OpenId Connect going on at the OpenId Connect mailing
>>>> list.
>>>>
>>>> I'm very much interested to find a solution within the OAuth realm as
>>>> I'm not interested to either implement two solutions (for OpenId Connect
>>>> and OAuth) or adopt a OpenId-specific solution to OAuth (use id! tokens
>>>> in the front channel). I therefore would like to see progress and
>>>> propose to continue the discussion regarding mitigations for both
>>>> threats.
>>>>
>>>> https://tools.ietf.org/html/draft-ietf-oauth-mix-up-mitigation-00
>>>> proposes reasonable mitigations for both attacks. There are alternatives
>>>> as well:
>>>> - mix up:
>>>> -- AS specific redirect uris
>>>> -- Meta data/turi
>>>> (https://tools.ietf.org/html/draft-sakimura-oauth-meta-07#section-5)
>>>> - CnP:
>>>> -- use of the nonce parameter (as a distinct mitigation beside state for
>>>> counter XSRF)
>>>>
>>>> Anyone having an opinion?
>>>>
>>>> best regards,
>>>> Torsten.
>>>>
>>>> _______________________________________________
>>>> 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
>>>
>>>
>>> --
> Nat Sakimura
> Chairman of the Board, OpenID Foundation
> Trustee, Kantara Initiative
>
-- 
Nat Sakimura
Chairman of the Board, OpenID Foundation
Trustee, Kantara Initiative