Over 600,000 Macs have been infected with the Flashback trojan horse. This was originally introduced last year by tricking people into installing it through social engineering. However, the latest version uses exploits found in Java to weasel itself into an unsuspecting Macintoshes. Once infected, the system becomes part of a network than can be used to attack networks, turn over user's information, or hack into other systems. Users can download a patch for Java that will assist in blocking the attack.