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Re: Fixing exchange of host keys in the SSH key exchange

Peter Gutmann <pgut001@cs.auckland.ac.nz> Mon, 27 March 2017 05:47 UTC

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From: Peter Gutmann <pgut001@cs.auckland.ac.nz>
To: Mouse <mouse@Rodents-Montreal.ORG>, "ietf-ssh@netbsd.org" <ietf-ssh@netbsd.org>
Subject: Re: Fixing exchange of host keys in the SSH key exchange
Thread-Topic: Fixing exchange of host keys in the SSH key exchange
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Date: Mon, 27 Mar 2017 05:47:28 +0000
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References: <2216143EDEE342A3A5C9BB786F7FEF7A@Khan> <201703231224.IAA22091@Stone.Rodents-Montreal.ORG><589D55C2CF5942E9910482788CBDB445@Khan> <201703260243.WAA05983@Stone.Rodents-Montreal.ORG> <B27F1BAE8F974449B6EE8B7DF50ED3A9@Khan>, <201703270327.XAA25497@Stone.Rodents-Montreal.ORG>
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Mouse <mouse@Rodents-Montreal.ORG> writes:

>(They were the SSH listeners on devices such as switches.)

It seems to be an unwritten law that big-iron networking hardware has to run
15-to-20-year-old unpatched copies of some version of SSH that the
switch/router vendor found in a dumpster somewhere.  I've seen late-1990s
ssh.com implementations as recently as a few years ago, which is why I have to
keep active old SSH bug-workarounds that should have been retired a decade or
more ago.  Being able to remotely crash a carrier-grade router [0] by sending
it an SSH option it didn't expect is a bit disturbing... this is why my code
grew a dump-full-packet-trace-to-debug-console option at some point in the
past.

Peter.

[0] I guess the SSH part is excluded from the carrier-grade categorisation.

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