Conflicker worm in the recent past has garnered a lot of attention by attacking nearly 9 million PC's. According to the Internet Storm Center, which tracks virus infections and Internet attacks, Conficker can spread in three ways. First, it attacks a vulnerability in the Microsoft Server service. Second, Conficker can attempt to guess or 'brute force' administrator passwords used by local networks and spread through network shares.And third, the worm infects removable devices and network shares with an autorun file that executes as soon as a USB drive or other infected device is connected to a victim PC.