Conficker.e
Not only does Conficker.e infect new machines, but it also updates computers infected with previous versions of the worm. The trojan spreads via MS08-067 security exploits. Conficker.e functions in pretty much the same way as its forerunners, Conficker B++ and Conficker.C. The worm joins compromised machines into a botnet - a collection of compromised computers running software under a common command-and-control infrastructure. The computer then might be used for DDoS attacks and spam attacks. Conficker.e (also known as Downadup) also establishes hidden remote access to the PC.