Just finished adding a bunch of variants of Java/Needy Trojan family. This week we have added from Needy.D to Needy.I. Basically all of them are quite similar in functionality. A Trojan is downloaded from malicous web site and executes using vulnerability in Internet Exlorer Java runtime, and changes IE homepage and search settings and optionally download more trojans to the system.
The best protection against these trojans is to make sure that Internet Explorer has the latest security patches.