Updates on the GIFAR vulnerability
First, I'd like to congratulate Billy Rios, Nate McFeters, Rob Carter, and John Heasman as the GIFAR Java attack was selected as the top web hacking attack technique for 2008. I had the opportunity to meet Nate McFeters at a STLSec event, and I was impressed by how down to earth and knowledgeable he is.
Second, through the post on Jeremiah's blog I learned of this post by Billy Rios. It contains a great write-up of a practical attack using GIFARs, using Google as an example.
Finally, Sun has patched this particular attack vector. The Sun advisory is #244988. This is patched as of versions JDK and JRE 6 Update 11, JDK and JRE 5.0 Update 17, and SDK and JRE 1.4.2_19.

