[TLS] DoS risks from draft-vkrasnov-tls-jumpstart-00

Watson Ladd <watsonbladd@gmail.com> Fri, 15 May 2015 02:38 UTC

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Date: Thu, 14 May 2015 19:37:58 -0700
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From: Watson Ladd <watsonbladd@gmail.com>
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Subject: [TLS] DoS risks from draft-vkrasnov-tls-jumpstart-00
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Dear all,

I'd like to explain some of the ways in which
draft-vkrasnov-tls-jumpstart may provide opportunity for mischief. The
first, and most obvious, is that responses are considerably larger
than requests, leading to amplification. The second is that each
request creates state that is supposed to be stored on the server,
leading to exhaustion of server resources. There does not appear to be
a cookie mechanism to mitigate this problem.

For resumed connections these problems are much less serious. It may
be that resumption only is a better fit for this approach to latency
reduction.

Sincerely,
Watson Ladd