Re: [TLS] Rizzo claims implementation attach, should be interesting

Martin Rex <mrex@sap.com> Tue, 20 September 2011 00:50 UTC

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From: Martin Rex <mrex@sap.com>
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To: asteingruebl@paypal-inc.com (Steingruebl Andy)
Date: Tue, 20 Sep 2011 02:53:05 +0200 (MEST)
In-Reply-To: <5EE049BA3C6538409BBE6F1760F328ABEBD61B6ACA@DEN-MEXMS-001.corp.ebay.com> from "Steingruebl, Andy" at Sep 19, 11 05:42:17 pm
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Subject: Re: [TLS] Rizzo claims implementation attach, should be interesting
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Steingruebl, Andy wrote:
> 
> Martin Rex wrote:
> > 
> > Tim Dierks wrote:
> > >
> > > Does anyone have any ideas what Rizzo may be announcing @ ekoparty?
> > >
> > > http://www.ekoparty.org/2011/juliano-rizzo.php
> > >
> > > BEAST: Surprising crypto attack against HTTPS
> > 
> > The first details seem to be leaking:
> > 
> > http://threatpost.com/en_us/blogs/new-attack-breaks-confidentiality-
> > model-ssl-allows-theft-encrypted-cookies-091611
> 
> More "details" here:
> 
> http://www.theregister.co.uk/2011/09/19/beast_exploits_paypal_ssl/
> 
> Or at least more confirming quotes from the researchers about how
> quickly the can perform the attack.

It seem to be a huge hype an exxageration of the problem.
There is *no* problem in SSLv3 or TLSv1.0.  This particular attack
is a very clear "Man-in-the-Browser" attack enabled solely by the
entirely braindead (lack-of) security in common Web Browsers.

Since the attack happens entirely at the browser, it should IMHO
the browser's duty to fix this.


Potential server-side mitigation of the problem:

  - disable HTTP request pipelining (aka Connect: keep-alive)

  - avoid CBC-based cipher suites (at least when SSLv3 or TLSv1.0
    is negotiated), and use RC4-128 instead.


-Martin