Bot nets, collections of compromised computers controlled by a single person or group, have become more pervasive and increasingly focused on identity theft and installing spyware.

The large networks of compromised computers are now a tool for groups of criminals bent on making money through identity fraud or adware installation. A person whose computer is infected with bot software runs the risk of having sensitive information such as account passwords and credit card numbers sent to the controller of the network.

At least a million computers worldwide are unwitting hosts to bot software– a conservative estimate.