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SSL Renegotiation Attack Becomes Real
rastos1 and several other readers noted that the SSL vulnerability we discussed a couple of weeks back, which some researchers had claimed was too theoretical to worry about, has now been demonstrated by exploit. The attack description is available on securegoose.org. "A Turkish grad student has devised a serious, real-world attack on Twitter that targeted a recently discovered vulnerability in the SSL protocol. The exploit by Anil Kurmus is significant because it successfully targeted the so-called SSL renegotiation bug to steal Twitter login credentials that passed through encrypted data streams. All in all, a man in the middle is able to steal the credentials of a user authenticating himself through HTTPS to a trusted website."
Or 'Goodness, old boy, that's dashed inconvenient!' for us Brits. So two phrases. Gosh.
It's nice to have a Sandbox for testing the latest and greatest hacks and security protocols, where no one cares about the user and/or what information they've posted on the site.
Important part of the article:
The only reason it was exploitable was because of Twitter's API. Understandably, I'm not too worried about the rest of the Internet going down in flames any time soon.
A good source of info about what this attack is and how serious it is can be found at
http://www.educatedguesswork.org/2009/11/understanding_the_tls_renegoti.html
Well, I suppose it's my own fault for trusting The Register. After reading the first article, I got curious and went on to check out the technical details of the exploit. What The Register phrases as "it's Twitter's API's fault" is actually "holy fuck you can POST the whole HTTP message to arbitrary locations (hosted on the same server, anyway)", which is a tad bit worse. While the Internet still isn't going to go down in flames, this does open up potential for some sites to get some nasty burns, and in a way they almost surely won't already be protected against, even if the developers aren't idiots.
You could actually read the rest of the article, in which it indicates that this is not merely a CSRF-equivalent attack (as it was originally taken to be), as opposed to just reposting an out-of-context snippet chosen to make the editors look bad.
Apparently just a specific subset, though it would probably be easy to find other websites with vulnerabilities similar to Twitter's. Basically, although he couldn't directly read the encrypted user name and password passed between Twitter servers and clients, he was able to exploit functionality in Twitter's public API to log the data from the request to a location he could access, including the stuff that had been encrypted in transit.
It should be illegal to say that freedom of speech should be limited.
Obviously such attacks are possible because of the application security, renegotiation just makes it easier. BTW, here is a tool to check if your server is vulnerable to renegotiation attacks: https://www.ssllabs.com/ssldb/
BTW, clients (e.g. browsers) are pretty save - there is NO need to panic!!
You are forgiven for the error. Anyone using a letter that could be mistaken for a number in any software version string should be cockpunched with brass knuckles coated in broken glass and lemon juice
People ought to stop blaming "The Web" as being inherently insecure. As much as you drill down into it, when party1 communicates with party2 and party1 isn't intimately familiar with party2's identity then transactions of information will always be prone to being exploited. This goes for human interaction (face to face) as well as human-to-computer interaction.
Frankly, I'd rather have an insecure internet than have an internet where everyone's identity was fully exposed and documented.