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

[Nomad On Walkabout <[e-mail]>]

Hi John,

I suggest you read the first few sections of the OAuth spec as it may explain better the use of terms in OAuth as they are a little different due to implementation. In this case I believe you mean "Resource Owner" as the "Client"'s certificate is not going to be a privacy issue unless as stated before the "client" is a third party entity and is likely not going to be effected by privacy concerns as I understand the in this case. Also in the first few sections of the OAuth RFC, security (and privacy) concerns are addressed stating that the latest version of SSL/TLS possible should be in use. (At the time of writing TLSv1.2 was the latest)

Cheers,
Carl
[e-mail]

On 11/1/18, 9:01 PM, "OAuth on behalf of John-Mark Gurney" <[e-mail] on behalf of [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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