Re: [conex] Stephen Farrell's No Objection on draft-ietf-conex-destopt-09: (with COMMENT)

Stephen Farrell <stephen.farrell@cs.tcd.ie> Tue, 06 October 2015 01:02 UTC

Return-Path: <stephen.farrell@cs.tcd.ie>
X-Original-To: conex@ietfa.amsl.com
Delivered-To: conex@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id EFD241B3006; Mon, 5 Oct 2015 18:02:55 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.311
X-Spam-Level:
X-Spam-Status: No, score=-4.311 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001, T_RP_MATCHES_RCVD=-0.01] autolearn=ham
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id tm0e3Vvy-sUF; Mon, 5 Oct 2015 18:02:55 -0700 (PDT)
Received: from mercury.scss.tcd.ie (mercury.scss.tcd.ie [134.226.56.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id D12191B3005; Mon, 5 Oct 2015 18:02:54 -0700 (PDT)
Received: from localhost (localhost [127.0.0.1]) by mercury.scss.tcd.ie (Postfix) with ESMTP id 92CC9BE49; Tue, 6 Oct 2015 02:02:53 +0100 (IST)
X-Virus-Scanned: Debian amavisd-new at scss.tcd.ie
Received: from mercury.scss.tcd.ie ([127.0.0.1]) by localhost (mercury.scss.tcd.ie [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Wv-qokUTgBhE; Tue, 6 Oct 2015 02:02:52 +0100 (IST)
Received: from [10.87.48.73] (unknown [86.46.26.211]) by mercury.scss.tcd.ie (Postfix) with ESMTPSA id 79F3ABE35; Tue, 6 Oct 2015 02:02:49 +0100 (IST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cs.tcd.ie; s=mail; t=1444093372; bh=ZNl3wzEtmQKL2a1rIZsOtFkgJAZWMwAAD/oPZJa9pSQ=; h=Subject:To:References:Cc:From:Date:In-Reply-To:From; b=O7o4RfHE4zxBhq57XLkk8k0n3q6St1stOWCAcjDF7er3AB7bjkttaQHVQoPlzr2ws mQ14k2Jf7WIIq4DjJG6wvvslIkQhC8ayAyjr9at18CpBmNpvpeUl9SJPaD3iLtQ3Ra SAmb9OHOBeZKLzXFhJPCrKFLTDJIaSbvDWv/iz64=
To: Bob Briscoe <ietf@bobbriscoe.net>, Suresh Krishnan <suresh.krishnan@ericsson.com>
References: <20151001000655.11590.32411.idtracker@ietfa.amsl.com> <E87B771635882B4BA20096B589152EF63A97724C@eusaamb107.ericsson.se> <560CEF4E.5080409@cs.tcd.ie> <560DAE68.60401@bobbriscoe.net> <560E45E2.2040809@cs.tcd.ie> <56130B0E.3000906@bobbriscoe.net>
From: Stephen Farrell <stephen.farrell@cs.tcd.ie>
Openpgp: id=D66EA7906F0B897FB2E97D582F3C8736805F8DA2; url=
Message-ID: <56131DB8.1040109@cs.tcd.ie>
Date: Tue, 6 Oct 2015 02:02:48 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0
MIME-Version: 1.0
In-Reply-To: <56130B0E.3000906@bobbriscoe.net>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Archived-At: <http://mailarchive.ietf.org/arch/msg/conex/J2O5RQ6So2GvLRpnqKo9f4f9eAo>
Cc: "draft-ietf-conex-destopt.ad@ietf.org" <draft-ietf-conex-destopt.ad@ietf.org>, "conex-chairs@ietf.org" <conex-chairs@ietf.org>, The IESG <iesg@ietf.org>, "conex@ietf.org" <conex@ietf.org>, "draft-ietf-conex-destopt@ietf.org" <draft-ietf-conex-destopt@ietf.org>
Subject: Re: [conex] Stephen Farrell's No Objection on draft-ietf-conex-destopt-09: (with COMMENT)
X-BeenThere: conex@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Congestion Exposure working group discussion list <conex.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/conex>, <mailto:conex-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/conex/>
List-Post: <mailto:conex@ietf.org>
List-Help: <mailto:conex-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/conex>, <mailto:conex-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 06 Oct 2015 01:02:56 -0000

Hiya,

On 06/10/15 00:43, Bob Briscoe wrote:
> 
> [Proposal #2]
> A network-based attacker could alter ConEx information to fool an audit
> function in a downstream network into discarding packets. However,
> otherexisting attacks from one network on another such a TTL expiry
> attacks are more damaging (because ConEx audit discards silently) and
> less traceable (because TTL is meant to change, whereas CDO is not).

That's better, yes.

Probably no need to address it in this document but I guess our
assumptions about other existing attacks might change as more and
more network traffic is ciphertext at various layers. I'm also
generally leery of arguments of the form "no need to do something
here as there's a worse thing there" since those encourage us to
do nothing anywhere, so I'd lose that kind of language if it can
be done.

S.