Botnets Used to Cheat Ad Programs

Honeynet.org have release a paper on botnets where they list the uses of thoses small programs to cheat ad banners and PPC programs :

Installing Advertisement Addons and Browser Helper Objects (BHOs)

• Botnets can also be used to gain financial advantages. This works by setting up a fake website with some advertisements: The operator of this website negotiates a deal with some hosting companies that pay for clicks on ad. With the help of a botnet, these clicks can be "automated" so that instantly a few thousand bots click on the pop-ups. This process can be further enhanced if the bot hijacks the start-page of a compromised machine so that the "clicks" are executed each time the victim uses the browser.

Google AdSense abuse

• A similar abuse is also possible with Google's AdSense program: AdSense offers companies the possibility to display Google advertisements on their own website and earn money this way. The company earns money due to clicks on theses ad, for example per 10.000 clicks in one month. An attacker can abuse this program by leveraging his botnet to click on these advertisements in an automated fashion and thus artificially increments the click counter. This kind of usage for botnets is relatively uncommon, but not a bad idea from an attacker's perspective.