Re: [btns] rfc 5387

Nicolas Williams <Nicolas.Williams@sun.com> Tue, 05 May 2009 22:11 UTC

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Date: Tue, 5 May 2009 16:48:04 -0500
From: Nicolas Williams <Nicolas.Williams@sun.com>
To: Joe Touch <touch@ISI.EDU>
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Cc: Alan Johnston <alan@ese.wustl.edu>, btns@ietf.org, jb27@cec.wustl.edu
Subject: Re: [btns] rfc 5387
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On Tue, May 05, 2009 at 02:43:16PM -0700, Joe Touch wrote:
> Nicolas Williams wrote:
> > On Thu, Apr 23, 2009 at 04:15:59PM -0500, jb27@cec.wustl.edu wrote:
> >> -From section 4, BTNS protects security associations after they are
> >> established by reducing vulnerability to attacks from parties that are not
> >> participants in the association.?  Doest this include MitM attacks?
> > 
> > Yes.
> 
> Agreed - *after* the BTNS association is established, it does protect
> from further MITM attacks.

I should clarify one more thing: BTNS protects against MITMs after the
initial exchange IFF either leap-of-faith (PAD updates) is done, and/or
connection-latching is used.  If you do neither then you get no MITM
protection at all.

BTNS protects against MITMs in the initial connection IFF either
out-of-band authentication of peer ID is done, and/or in-band
authentication + channel binding is done.  If you do neither then you
get no MITM protection on the initial connection.

Nico
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