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Re: [TLS] Working Group Last Call for draft-ietf-tls-downgrade-scsv-00

Hanno Böck <hanno@hboeck.de> Wed, 15 October 2014 12:36 UTC

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Date: Wed, 15 Oct 2014 14:36:11 +0200
From: Hanno Böck <hanno@hboeck.de>
To: "Salz, Rich" <rsalz@akamai.com>, "tls@ietf.org" <tls@ietf.org>
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Subject: Re: [TLS] Working Group Last Call for draft-ietf-tls-downgrade-scsv-00
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Am Wed, 15 Oct 2014 08:19:59 -0400
schrieb "Salz, Rich" <rsalz@akamai.com>:

> We (Akamai) see less than 1% SSLv2 and SSLv3 traffic globally and
> it's concentrated to a few particular clients.  Those clients are
> important to some customers. They want modern browsers to be
> protected, by not falling back to SSLv3, but they don't want to cut
> off those legacy clients.  SCSV fallback solves that problem. It also
> will solve a problem when some browsers try to use TLS 1.3 but
> servers haven't been updated.

That's not really the point we're talking about.
SCSV is as far as I understood not to support SSLv2/3. SSLv3 should be
almost dead after POODLE (and I don't shed a tear).

What SCSV is about is a workaround to a workaround to support
servers that don't support in-protocol-downgrades. I think this has
been called "Protocol version intolerance" in the past (however I think
"protocol version breakage" would be a better term).

So the number I want to see is: How many servers are there that are not
capable of correctly negotiating the SSL/TLS versions they support?

-- 
Hanno Böck
http://hboeck.de/

mail/jabber: hanno@hboeck.de
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