Re: [jose] Use of ECDH-ES in JWE

On Fri, Feb 24, 2017 at 7:40 AM, Antonio Sanso <asanso@adobe.com> wrote:
> Thanks a lot guys for the suggestions. I will take a stub so and submit an
> errata…

Thank you.  List members - please review and I'll accept the errata
once language is agreed to.  I also think this is good for future
document updates.

>
> regards
>
> antonio
>
> On Feb 22, 2017, at 4:32 AM, Jim Schaad <ietf@augustcellars.com> wrote:
>
> I would welcome an errata even for the people that might miss it from
> reading the documents.  If nothing else, it gives us some hints about what
> things need to be dealt with in the (presumably) next revisions of the
> documents.
>
> Jim
>
>
> From: jose [mailto:jose-bounces@ietf.org] On Behalf Of Brian Campbell
> Sent: Tuesday, February 21, 2017 12:23 PM
> To: John Bradley <ve7jtb@ve7jtb.com>
> Cc: Antonio Sanso <asanso@adobe.com>; jose@ietf.org; Vladimir Dzhuvinov
> <vladimir@connect2id.com>
> Subject: Re: [jose] Use of ECDH-ES in JWE
>
>
> This seems similar in nature to some of the security consideration advice in
> JWE https://tools.ietf.org/html/rfc7516#section-11.4 and
> https://tools.ietf.org/html/rfc7516#section-11.5 and JWA
> https://tools.ietf.org/html/rfc7518#section-8.3 and
> https://tools.ietf.org/html/rfc7518#section-8.4 that an average implementer
> (like myself) would very likely not be aware of unless some attention is
> called to it.
>
> The point about people missing the errata is totally legit. But in the
> absence of some other way to convey it, perhaps it'd be better to have it
> written down as errata than not at all? Maybe Antonio would be the one to
> submit an errata for RFC 7518 https://www.rfc-editor.org/errata.php ?
>
> Certification for JOSE/JWT libraries sounds interesting. Having an errata
> for this would serve as a reminder for at least one negative test that
> should be done in that, if/when it comes to pass.
>
> On Mon, Feb 13, 2017 at 8:34 AM, John Bradley <ve7jtb@ve7jtb.com> wrote:
>
> An errata is possible.   There is no way to update the original RFC.
>
> The problem tends to be that most developers miss the errata when reading
> specs if they ever look at the specs at all.
>
> We probably also need a more direct way to communicate this to library
> developers as well.
>
> In the OIDF we are talking about developing a certification for JOSE/JWT
> libraries like we have for overall server implementations.
>
> John B.
>
>
>
>> On Feb 13, 2017, at 7:57 AM, Antonio Sanso <asanso@adobe.com> wrote:
>>
>> hi Vladimir,
>>
>> thanks a lot for taking the time and verifying.
>> I really think it should be mentioned somewhere.
>> The problem is that Elliptic Curves are over the head of many
>> people/developer and it should be at least
>> some reference on the JOSE spec about defending against this attack.
>> Said that I have so far reviewed 3 implementations and all 3 were somehow
>> vulnerable. And counting….
>>
>> regards
>>
>> antonio
>>
>> On Feb 13, 2017, at 7:41 AM, Vladimir Dzhuvinov <vladimir@connect2id.com>
>> wrote:
>>
>>> Hi Antonio,
>>>
>>> Thank you for making us aware of this.
>>>
>>> I just checked the ECDH-ES section in JWA, and the curve check
>>> apparently hasn't been mentioned:
>>>
>>> https://tools.ietf.org/html/rfc7518#section-4.6
>>>
>>> It's not in the security considerations either:
>>>
>>> https://tools.ietf.org/html/rfc7518#section-8
>>>
>>>
>>> Vladimir
>>>
>>> On 09/02/17 12:39, Antonio Sanso wrote:
>>>> hi all,
>>>>
>>>> this mail is highly inspired from a research done by Quan Nguyen [0].
>>>>
>>>> As he discovered and mention in his talk there is an high chance the
>>>> JOSE libraries implementing ECDH-ES in JWE are vulnerable to invalid curve
>>>> attack.
>>>> Now I read the JWA spec and I did not find any mention that the
>>>> ephemeral public key contained in the message should be validate in order to
>>>> be on the curve.
>>>> Did I miss this advice in the spec or is it just missing? If it is not
>>>> clear enough the outcome of the attack will be the attacker completely
>>>> recover the private static key of the receiver.
>>>> Quan already found a pretty well known JOSE library vulnerable to it. So
>>>> did I.
>>>>
>>>> WDYT?
>>>>
>>>> regards
>>>>
>>>> antonio
>>>>
>>>> [0] https://research.google.com/pubs/pub45790.html
>>>> [1] https://tools.ietf.org/html/rfc7518
>>>> _______________________________________________
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>>>> jose@ietf.org
>>>> https://www.ietf.org/mailman/listinfo/jose
>>>
>>>
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Best regards,
Kathleen