Re: [Spud] [Privsec-program] Detecting and Defeating TCP/IP Hypercookie Attacks

Joe Touch <> Fri, 29 July 2016 21:23 UTC

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To: Brian Trammell <>, Stephen Farrell <>
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From: Joe Touch <>
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Date: Fri, 29 Jul 2016 14:22:04 -0700
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Subject: Re: [Spud] [Privsec-program] Detecting and Defeating TCP/IP Hypercookie Attacks
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On 7/29/2016 9:22 AM, Brian Trammell wrote:
> hi Stephen,
>> Hi Brian,
>> On 29/07/16 13:33, Brian Trammell wrote:
>>> Greetings, all,
>>> During the PLUS BoF last week, concern was expressed that a generic
>>> signaling mechanism such as proposed opened two new attack surfaces:
>> ...
> Agreed that the analysis isn't where I'd like it to be yet. There are two major reasons for this. One, this draft is focused on in-band abuse of TCP and IP features (which seemed a good place to start) 

I don't think it is.

A user who doesn't want this sort of vulnerability inside the messages
they send needs to use integrity protection at least (perhaps also

A user cannot prevent vulnerabilities in layers they can't control
(e.g., along a tunnel used along a subset of the path).

It's not productive to try to analyze the weaknesses of protocols that
are not designed to be strong. They're weak. Move on, IMO.

The alternative is "hey, it's weak - we should make it strong". Doing
that ends up violating the Postel Principle. I.e., behaviors that are
otherwise legitimate are suddenly interpreted as deliberate and
malicious attacks when they were never specified as such.

That's not helpful, IMO.