It is a group of Internet-connected programs that interact with other related programs in order to perform a tasks. This can be keeping control of an Internet Relay Chat (IRC) channel, or it could be used to send spam email or it can even take part in a*- distributed denial-of-service attacks. A botnet gets its name from a combination of robot and network.
A computer can be infected with a botnet when they execute malicious software. This can be accomplished by luring users into making a download, exploiting web browser vulnerabilities, or running a Trojan horse program, which may come from an email attachment. This malware will install modules that allow the computer to be commanded and controlled by the botnet's operator. Many computer users are unaware that their computer is infected with bots. Depending on how it is written, a Trojan may delete itself, or remain present to update and maintain the modules. A bot might cause your exposed computer to slow down, display mysterious messages, or even crash.
The first botnet was first known during a lawsuit with Spammer Khan C. Smith in 2001 for the purpose of bulk spamming. A botnet's originator is known as a bot herder or bot master` and can control the group remotely, usually through IRC, and often for criminal purposes. This server is known as the command-and-control (C&C) server. Though rare, more experienced botnet operators program command protocols from scratch. These protocols include a server program, a client program for operation, and the program that embeds the client on the victim’s machine. These communicate over a network, using a unique encryption to Protect against detection or intrusion into the botnet. A bot typically runs hidden and uses a covert channel (IRC) standard, Twitter, or IM) to communicate with its C&C server. Normally, the agent has compromised multiple systems using various tools such as; exploits, buffer overflows, as well as others. Newer bots can...