Unfortunately for the owners of infected computers, botmasters are interested in far more than DDoS attacks.
"Once the host is compromised, it becomes part of a botnet and it connects to some kind of command and control infrastructure," says Giovanni Vigna, University of California, Santa Barbara professor and LastLine, Inc. co-founder. "The bots report back and say, 'Hey, what should I do?'"
Botmasters have numerous underhanded answers to this question, turning host computers into cybercrime weapons, spam-distrusters, spies or even cash machines.
"There are bots out there designed not to attack third parties, but to steal information off your computer," says Stewart. "Or they take money out of your bank account. So there's definitely a risk to the individual."
In other words, this isn't simply a matter of vandalism or hacktivism - it's about stealing your bandwidth, your money and your identity.
Fighting Back Against Botnets
How can we fight back against millions of zombie computers yoked to the self-serving whims of nefarious botmasters? Individually, a lot of it comes down to maintenance and common sense.