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

Mirja K├╝hlewind <mirja.kuehlewind@tik.ee.ethz.ch> Thu, 08 October 2015 16:03 UTC

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To: Stephen Farrell <stephen.farrell@cs.tcd.ie>, Bob Briscoe <ietf@bobbriscoe.net>, Suresh Krishnan <suresh.krishnan@ericsson.com>
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Date: Thu, 8 Oct 2015 18:02:44 +0200
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Subject: Re: [conex] Stephen Farrell's No Objection on draft-ietf-conex-destopt-09: (with COMMENT)
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Hi,

I'm fine with the text below. But a quick question: Is there really a case 
where the attacker would alter the packet to make another network potentially 
drop the packet, instead of juts dropping it on its own?

Mirja


On 06.10.2015 03:02, Stephen Farrell wrote:
>
> 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.
>