From Businessweek: Cyber weapons

http://www.businessweek.com/printer/magazine/cyber-weapons-the-new-arms-race-07212011.html

"To deal with the Code War, which amounts to a constant state of threat, governments and companies can always try to develop their own technology. As with smart bombs, fighter jets, and other real-world countermeasures, though, it’s often easier to buy than build. 'The hacking industry is way ahead in terms of being able to deploy something like a massive botnet,' says Amichai Shulman, chief technology officer at Imperva, a security specialist. 'If a nation wants to launch an attack that distributes some kind of malware, it makes more sense for them to just rent an existing botnet.'”