Re: [OAUTH-WG] security considerations for draft-ietf-oauth-mtls-12

[Brian Campbell <[e-mail]>]

That's fair. I'll see if maybe I can piece together some reasonable text
about it and/or will also try to discuss it with the WG this week in
Bangkok.

On Fri, Nov 2, 2018, 3:18 AM John-Mark Gurney <[e-mail] wrote:

> I do not have a good enough understanding of OAuth nor how it is used
> in this draft to be able to write a proper security considerations
> section about it.  You mention that the OAuth certification is
> different than one for client cert authentication, but as I don't know
> the standard well enough, I do not know the implications of it.
>
> Even if the paragraph reads something like: Though client certs are
> public in TLS versions 1.2 and before, they are not a privacy concern
> because of x, y and z.  This would allow people who are reviewing it
> to understand why it is not a privacy issue.
>
> I only briefly reviewed this document because a coworker asked about
> it, but I raised this concern because it was not mentioned in the
> security considerations section.
>
> On Thu, Nov 1, 2018 at 7:37 AM Brian Campbell
> <[e-mail]> wrote:
> >
> > To be honest, I thought that was a relatively well known aspect of TLS
> 1.2 (and prior) and a noted difference of the new features in TLS 1.3.
> Also, I'd note that we're well past WGCL for this document. But, with that
> said, I suppose adding some privacy considerations text on the subject is
> worthwhile. Would you propose some text for the WG to consider, John-Mark?
> Bearing in mind that the implications of a certificate presented by, and
> representing, an OAuth client are somewhat different than for an end-user
> doing client cert authentication.
> >
> >
> >
> >
> > On Wed, Oct 31, 2018 at 4:12 PM John-Mark Gurney <
> [e-mail]> wrote:
> >>
> >> I would suggest that the security considerations section of
> >> draft-ietf-oauth-mtls-12 be expanded to include the privacy
> >> implications of using this on versions of TLS before 1.3.  On all
> >> versions of TLS before 1.3, the client cert is not encrypted and can
> >> be used by third parties to monitor and track users.  I recently
> >> posted a blog entry about this:
> >>
> https://blog.funkthat.com/2018/10/tls-client-authentication-leaks-user.html
> >>
> >> Thanks.
> >>
> >> John-Mark Gurney
> >>
> >> _______________________________________________
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> >> [e-mail]
> >> https://www.ietf.org/mailman/listinfo/oauth
> >
> >
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> --
> John-Mark Gurney
> Principal Security Architect
>

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