Oct 16, 2014; 13:54
Steve Piercy - Website Builder
Fwd: Bulletproof TLS Newsletter: POODLE attack on SSL 3
I get this newsletter because I signed up for the excellent free
ebook, "OpenSSL Cookbook".
https://www.feistyduck.com/books/openssl-cookbook/
The author publishes frequent updates, saving me a lot of
Googling for authoritative information.
--steve
====== Forwarded Message =====Date: 10/16/14 7:57 PM
Received: 10/16/14 2:57 PM -0400
From: ivanr@webkreator.com (Ivan Ristic)
After days of persistent rumours, a serious SSL 3 vulnerability was
announced late on October 14th [1]. The so-called POODLE attack exploits
the CBC padding as implemented in SSL 3 to retrieve fragments of
encrypted information (e.g., cookies). The attack scenario is complex:
the attacker must execute an active network attack that is a combination
of network-level manipulation and malicious JavaScript executing
in the
victim's browser. But, if those two preconditions are met, the attack
itself is relatively straightforward. If you're interested in the
details, the original announcement comes with a short paper, but
I also
recommend Adam Langley's blog post [2].
We haven't seen a proof of concept yet, but given that the
attack is not
overly complex, it's reasonable to expect that someone will
write it
sooner or later.
The good news is that this problem affects only SSL 3, but the
bad news
is that it's still possible to downgrade modern browsers from whatever
best version they support all the way down to the vulnerable protocol.
(I discuss this in the "Protocol Downgrade Attacks" section in Chapter
6 of Bulletproof SSL and TLS.)
There are two things you should do: 1) disable SSL 3 in your browser
and 2) if at all possible disable SSL 3 in your servers. Please refer
to my blog post for a longer discussion [3]. Scott Helme has a detailed
blog post with step-by-step instructions for popular browsers and
servers [4].
On the SSL Labs side [5], we released three new features
yesterday to
address POODLE: 1) warnings for vulnerable servers, 2) detection
of the
support for TLS_FALLBACK_SCSV (you'll read more about it in my
blog or,
better, in my book) and 3) adding detection of SSL 3 support to the
client test.
[1] This POODLE bites: exploiting the SSL 3.0 fallback
http://googleonlinesecurity.blogspot.co.uk/2014/10/this-poodle-bites-exploiting-ssl-30.html
[2] POODLE attacks on SSLv3
https://www.imperialviolet.org/2014/10/14/poodle.html
[3] SSL 3 is dead, killed by the POODLE attack
http://blog.ivanristic.com/2014/10/ssl3-is-dead-killed-by-poodle.html
[4] SSL v3 goes to the dogs - POODLE kills off protocol
https://scotthelme.co.uk/sslv3-goes-to-the-dogs-poodle-kills-off-protocol
[5] SSL Labs
https://www.ssllabs.com
------------------------------------------------------------------------
Thanks,
Ivan
-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
Steve Piercy Website Builder Soquel, CA
<web@StevePiercy.com> <http://www.StevePiercy.com/>
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Oct 17, 2014; 12:14
Bil Corry
Re: Bulletproof TLS Newsletter: POODLE attack on SSL 3
Oct 17, 2014; 03:44
Steve Piercy - Website Builder
Re: Bulletproof TLS Newsletter: POODLE attack on SSL 3