After the code leak MS is now advising customers to move to IE6SP1. Although they are still down playing the risks of having their code all over the internet they are suggesting users quickly move to the new version.

"Most of IE code is what was leaked," said Chris Jones, corporate vice president in the Windows Core Operating System Division, about the NT 4.0 and Windows 2000 code that leaked. "We don't believe [customers will be affected] so as long as they're current on the latest versions of IE. They need to move to IE 6 and security patches and service packs."
This quote came from:

Sounds to me like Microsoft knows that the older versions of IE are going to get hit hard by the underground but doesn't want to admit it.