The U.S. Department of Defense believes a computer worm (agent.btz), introduced into their heavily protected (not connected to the Internet) SIPRNet network three years ago, was developed by Russia. It was three years ago that agent.btz got into the top secret Department of Defense network when a soldier in Central Command, stationed in the Middle East, plugged an agent.btz infected thumb drive into a laptop, connected to the secure net. Despite three years of efforts, the Department of Defense has not been able to completely clean out agent.btz. New versions of agent.btz have shown up in other U.S. government networks. Hostile software like agent.btz is programmed to constantly try and duplicate itself and move to other networks. That’s what a worm does. But agent.btz also seeks to find a network that is connected to the Internet, so that it can transmit out data it has collected. This is the perfect spy, and there are more of them out there every month. There are not only more of them, but they get more capable. New ones are programmed to evade defenses (anti-virus software) and most of them are equipped to insert them onto your hard disk so that they are difficult to detect.