Re: [TLS] Working Group Last Call for draft-ietf-tls-pwd

"Dan Harkins" <dharkins@lounge.org> Mon, 18 November 2013 21:51 UTC

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Date: Mon, 18 Nov 2013 13:51:28 -0800 (PST)
From: "Dan Harkins" <dharkins@lounge.org>
To: "Ralf Skyper Kaiser" <skyper@thc.org>
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Cc: tls@ietf.org
Subject: Re: [TLS] Working Group Last Call for draft-ietf-tls-pwd
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  Hi Ralf,

On Tue, November 12, 2013 2:28 am, Ralf Skyper Kaiser wrote:
> Hi,
>
> could not find it in the draft:
>
> the interoperability with draft-ietf-websec-key-pinning-08 should be
> mentioned explicitly to prevent
> an attack scenario. (e.g. user has pinned certificate for google.com.
> Attacker MITM forces
> client to do tls-pwd. Client should not allow this). E.g. once a host is
> pinned no other server-side
> auth mechanism should be allowed.

  If the client doesn't want to do TLS-pwd then it won't include the
mandatory extension in its client hello and it won't include any TLS-pwd
ciphersuites. I don't see how this attack happens.

  Perhaps the necessary requirements to deal with pinning certificates
for websec should be dealt with in the draft you mention.

  regards,

  Dan.