Supernova.D is a worm whose main objective is to spread and affect as many computers as possible.

The means it uses to spread are the peer-to-peer (P2P) file sharing programs and the instant messaging program MSN Messenger.

On the other hand, Supernova.D attacks certain websites by sending them continuous ping requests with the aim to make them stop responding.

Technical details can be found at this Panda Software page.