Re: [core] Consensus on using Echo to mitigate NoSec amplification?

Christian Amsüss <christian@amsuess.com> Mon, 02 March 2020 16:07 UTC

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Date: Mon, 02 Mar 2020 17:06:27 +0100
From: Christian Amsüss <christian@amsuess.com>
To: Carsten Bormann <cabo@tzi.org>
Cc: Core <core@ietf.org>
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Subject: Re: [core] Consensus on using Echo to mitigate NoSec amplification?
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On Tue, Feb 25, 2020 at 02:19:33PM +0100, Carsten Bormann wrote:
> Would the CoRE WG be fine with expanding the “updates 7252” text in
> draft-ietf-core-echo-request-tag to also include recommending this
> mitigation?  If you have a position on this, please reply to the list
> (or to the chairs) by March 2nd.

The current version stays as vague on what a larger response is as
RFC7252, I'd like to sharpen that when incorporating the above. My
current corner points are "a TCP SYN+ACK is 3 byte larger than a SYN",
and that NTP had a factor-200 amplification built in earlier versions
(though that's probably UDP-only, and headers'd make that more like
factor-50).

Is there any guidance that could be referenced, eg. an RFC that puts a
number to what consitutes an amplification attack vector? Even [RFC4732]
only talks of "significantly greater" packages.

Thanks
Christian

[RFC4732]: https://tools.ietf.org/html/rfc4732#section-3.1

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