The second half of the year 2010 saw stuxnet all over the news. Stuxnet, a cyber worm, is believed to be the world’s first publicly identified known cyber weapon. Such worms are designed to destroy the control system in a factory, refinery or even a nuclear power plant.
Computers are infected with such worm through websites, USB sticks or other external media drives connected to it. The worm causes no harm to its host and uses the host computer as a launch pad to attack a primary target. A botnet is created when the same worm infects multiple computers on a network. The primary target and the time of attack are set by a command center from where the botnet is controlled.
Since the worm behaves like any other legitimate software (uses stolen certificate) installed on the computer, antivirus software would have hard time identifying them. The worm has the tendency to change its characteristics to fit the environment of the host. Once it gets into a computer, it tends to go into a sleeping mode waiting for commands from the control center. However, the moment command is received from the command center; it wakes up and starts attacking a specific target. By the time an antivirus or a firewall picks up that behavior, it’s already late – the damage is already done at the target from a host system. If your computers are part of the host system of botnets, then you are liable for the damages.