Researcher busts into Twitter via SSL reneg hole

November 14, 2009 – 8:16 AM

A Swiss grad student has devised a serious, real-world attack on Twitter that targeted a recently discovered vulnerability in the secure sockets layer 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. When the flaw surfaced last week, many researchers dismissed it as an esoteric curiosity with little practical effect.

For one thing, the critics said, the protocol bug was hard to exploit. And for another, they said, even when it could be targeted, it achieved extremely limited results. The skepticism was understandable: While attackers could inject a small amount of text at the beginning of an authenticated SSL session, they were unable to read encrypted data that flowed between the two parties.

Despite those limitations, Kurmus was able to exploit the bug to steal Twitter usernames and passwords as they passed between client applications and Twitter’s servers, even though they were encrypted. He did it by injecting text that instructed Twitter’s application protocol interface to dump the contents of the web request into a Twitter message after they had been decrypted.

Source:
http://www.theregister.co.uk/2009/11/14/ssl_renegotiation_bug_exploited/