A botnet is a collection of compromised computers, each of which is known as a bot, connected to the Internet.
A botnet is a collection of compromised computers, each of which is known as a 'bot', connected to the Internet. When a computer is compromised by an attacker, there is often code within the malware that commands it to become part of a botnet. The "botmaster" or "bot herder" controls these compromised computers via standards-based network protocols such as IRC and http. Computers are most of the time recruited into a botnet by running malicious software. This may be achieved by a drive-by download exploiting web browser vulnerabilities, or by tricking the user into running a Trojan horse program, possibly in an email attachment. As with any malware, there is no general rule; the software controls the computer and can do anything. It will typically install modules which allow the computer to be commanded and controlled by the botnet's owner. The Trojan may delete itself, or may remain present to update and maintain the modules.
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