Botnets are a slightly different type of network than what we are usually familiar with. A botnet is a large group of computers (commonly known as ‘zombies’) that are networked together by somewhat of an evil overlord. That is, the computers and their users are unaware of being a part of this network, but were maliciously forced into it by the person in control of the botnet. They are usually controlled by, and the zombies connect to, an IRCD (Internet Relay Chat Daemon).

All of the nodes of this network share a few things in common. To begin, it is almost certain that they are being controlled unbeknownst to their users. Second, they all are running a piece of malicious software, a bot if you will, that is allowing the “master” to control them. They are all linked to one another, and in a large portion of cases are used against their will to carry out some type of attack as a single unit. This attack could include, but is not limited to: DDoS(Distributed Denial of Service), Spamming, Sniffing, Keylogging, Spreading themselves(worm), Advertisements, manipulation of polls, and in some cases large-scale identity theft.

The article I link below is discussing an interesting clashing between the botnet world and a social network. In this case, the internet social protest group going by the name of Anonymous utilized a special fusion of botnets to attack the church of scientology’s websites and shut them down. It was in response to Scientology requesting YouTube take a leaked video of a Scientology interview with Tom Cruise down for copyright infringement. The group Anonymous, having nothing but malicious intent for Scientology, gathered on an irc server and launched several attacks against Scientology. These attacks included a large Botnet DDoS attack successfully taking the Scientology homepage offline for several hours. This attack was run by fusing the botnets that several members of the Anonymous group had obtained illegally with 100s of Anonymous members’ computers as well. In this case, a large portion of the zombies on the network were aware of their computer’s participation in the botnet, and were allowing it to be controlled in order to achieve a common goal. This shows how the strength of social networks, and a cause/hope for change can create a botnet through social networking. At the same time worldwide peaceful protests were being held by members of Anonymous, as well as phone line attacks and blackfaxing of Scientology’s fax-machines. What started as an online protest group had evolved into several interesting networks of individuals, scarcely organized which also created more networks, such as the botnet[s] that they created for the attack.

http://www.scmagazineus.com/DDoS-hack-attack-targets-Church-of-Scientology/article/104588/