Bots can be automated to do just about anyhing, there really just scripts that are deisgned to do do network snooping. Here is the scenario, a new exploit is announced online, within minutes a cracker firs up his *nix box, code some PERL and bingo, this script is sent loose to probe networks looking for vulnerable PC's and delivering the result to a system in Finland.
First step is to keep your updates current, run a firewall, and dont use file sharing networks. I cannot stress this enough most malware comes thru those networkds even with Spyware running.