Information Security News
by Peter Bright
From the researchers that brought you BEAST and CRIME comes another attack against Secure Sockets Layer (SSL), one of the protocols that's used to secure Internet traffic from eavesdroppers both government and criminal.
Calling the new attack POODLE—that's "Padding Oracle On Downgraded Legacy Encryption"—the attack allows a man-in-the-middle, such as a malicious Wi-Fi hotspot or a compromised ISP, to extract data from secure HTTP connections. This in turn could let that attacker do things such as access online banking or e-mail systems. The flaw was documented by Bodo Möller, Thai Duong, and Krzysztof Kotowicz, all who work at Google. Thai Duong, working with Juliano Rizzo, described the similar BEAST attack in 2011, and the CRIME attack in 2012.
The attack depends on the fact that most Web servers and Web browsers allow the use of the ancient SSL version 3 protocol to secure their communications. Although SSL has been superseded by Transport Layer Security, it's still widely supported on both servers and clients alike, and is still required for compatibility with Internet Explorer 6. SSLv3, unlike TLS 1.0 or newer, omits validation of certain pieces of data that accompany each message. Attackers can use this weakness to decipher an individual byte at time of the encrypted data, and in so doing, extract the plain text of the message byte by byte.
Finally we got an official announcement. For all the details, jump straight to the original announcement . Below see the TL;DR; version:
The problem is limited to SSLv3. SSLv3 is often considered similar to TLSv1.0, but the two protocols are different.
SSLv3 had issues in the past. Remember the BEAST attack? It was never resolved (other then moving to TLS 1.1/2). The only alternative was to use a stream cipher like RC4, which had its own problems.
But this POODLE issue is different. With block ciphers, we have a second problem: What if the block to be encrypted is too short? In this case, padding is used to make up for the missing data. Since the padding isnt really considered part of the message, it is not covered by the MAC (message authorization code) that verified message integrity.
So what does this mean in real live? The impact is similar to the BEAST attack. An attacker may either play MitM, or may be able to decrypt parts of a message if the attacker is able to inject data into the connection just like in the BEAST attack. The attack allows one to decrypt one byte at a time, if the attacker is able to inject messages right after that byte that include only padding.
What should you do: Disable SSLv3. There is no patch for this. SSLv3 has reached the end of its useful life and should be retired.
This isnt a patch now. Give it some time, test it carefully, but get going with it. The other problem is that this is a client and a server issue. You need to disable SSLv3 on either. Start with the servers for highest impact, but then see what you can do about clients.
The other option to fix this problem is to use SSL implementations that take advantage of the TLS_FALLBACK_SCSV feature. This feature notifies the other side that you first tried the stronger cipher. This way, they can reject the downgrade attempt that may have been introduced by a MitM attack. But it isnt clear which implementations use this feature at this point, and which dont. A patch for OpenSSL 1.0.1 was released earlier today implementing TLS_FALLBACK_SCSV
To test if your server is vulnerable: Use https://ssltest.com
To test if your client is vulnerable: We setup a test page at https://www.poodletest.com">
To turn off SSLv3 support in Internet Explorer 11: Setting - Internet Options - Advanced Tab - Uncheck SSLv3 under Security. ">https://www.openssl.org/~bodo/ssl-poodle.pdf
To turn off SSLv3 support in Internet Explorer 11:
Setting - Internet Options - Advanced Tab - Uncheck SSLv3 under Security.
Yesterday, a number of news sites published speculative reports about a possible OpenSSLbug to be fixed today. According to these reports, the bug affects SSL 3, and is critical. Can-)
Initially, it looked like an OpenBSD patch lead to an answer, but turns out the patch was old (thx to those who wrote in and responded,in particular based on the tweet by @martijn_grooten). But instead, there are new leads now, in particular a discussion on Stackexchange . In this discussion, a comment by Thomas Pornin outlines how padding in SSLv3 can lead to MitM attacks. This would be an outright attack against the SSLv3 protocol, and less against a specificimplementation. It would affect clients as well as servers.
We will update this post as we learn more. At this point: Dont panic and wait for a patch from your respective vendor. We are not aware of any active exploitation of this problem, but please let us know if you see any evidence of that happening.
If you choose to disable SSLv3 on a server, but leave TLS 1.0 enabled, Windows XP with IE 6 will no longer be able to connect (but older versions of IE will be able to connect from Windows XP machines).
How can you test if a server supports SSLv3? Either use ssllabs.com, or using the openssl client: (if it connects, it supports SSLv3)
openssl s_client -ssl3 -connect [your web server]:443
How can I check if my browser can live without SSLv3? If you can read this, then you support TLSv1 or higher. I turned off SSLv3 support on this site for now. But pretty much all browsers support SSLv3.
You tell us not to panic, but you turned of SSLv3? Yes. I wanted to see what happens if I turn off SSLv3. So far, the only issue I found was Windows XP with IE 6, a configuration I probably dont want to support anyway.
Adobe published two security bulletins today:
APSB-22 : fixes 3 vulnerabilities in Adobe Flash Player as well as in Adobe Air. The vulnerabilities are rated with a priority of 1 for Flash Playerrunning onWindows and OS X , which means they have already been exploited in targeted attacks.
APSB-23  : another 3 vulnerabilities, but this time in Cold Fusion. The priority for these updates is 2which indicates that they have not yet been exploited in the wild.
Microsoft only published 8 instead of the promised 9 bulletins. Also, of particular interest is MS14-060 which was pre-announced by iSight Partners. iSighthas seen this vulnerability exploited in some APT style attacks against NATO/US military interests and attributes these attacks to Russia. Attacks like this have happened with many Office vulnerabilities in the past, but it is unusual for a company to announce the respective attacks and CVE numbers ahead of Microsofts bulletin release. Note that we got a total of 3 already exploited vulnerabilities in this months release. Don">MS14-059
Posted by InfoSec News on Oct 14http://krebsonsecurity.com/2014/10/whos-watching-your-webex/
Posted by InfoSec News on Oct 14http://arstechnica.com/security/2014/10/suspected-russian-sandworm-cyber-spies-targeted-nato-ukraine/
Posted by InfoSec News on Oct 14http://www.csoonline.com/article/2824563/social-engineering/the-human-os-overdue-for-a-social-engineering-patch.html
Posted by InfoSec News on Oct 14http://www.foxbusiness.com/economy-policy/2014/10/12/obama-said-to-warn-crippling-cyber-attack-potential/
Posted by InfoSec News on Oct 14http://venturebeat.com/2014/10/13/apparent-hackers-claim-they-have-stolen-nearly-7-million-dropbox-passwords/
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