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

[Brian Campbell <[e-mail]>]

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 <[e-mail]> 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 <[e-mail]> 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 <[e-mail]>
> 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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> >>> https://www.ietf.org/mailman/listinfo/jose
> >>
> >>
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