Understanding about what is a botnet becomes easier if one’s previous knowledge about zombies is tapped. Mythically, zombies transfer the infection to normal humans, which in turn create many other zombies resulting in a zombie army. Botnet is also known as a zombie army as a single infected computer, known as bot (also called zombie) can turn several other computers into bots by transferring the infection to them.
A computer becomes a bot, which is short for robot, when cyber criminals disperse malicious software around the world. This malicious software, turning computers into bots is also known as malware. Typically, cyber criminals use these bots to contaminate large numbers of computers to create a network or a botnet.
Criminals use these botnets to forward transmissions like viruses and spam email messages to other computers without the knowledge of their owners. Computers, when turned to bots, can thus perform automated tasks like attacking other computers and servers, and committing fraud.
By simple definition, therefore, botnet is a network of private computers which are infected with malware and serve the directives of some alien master spam or virus originator without the owner’s knowledge.
Most of the times, the computers which are compromised in this manner are home-based. This is due to the reason that home-based computers are less protected against malware and are therefore vulnerable in the face of most cybercrimes. A tip to find out whether your computer is a bot is to keep a check on its speed. If the computer is a part of botnet, its speed might slow down and it would inadvertently be helping criminals.
According to a report from Russian-based Kaspersky Labs, it is not spams, viruses or worms but actually botnets which currently pose the biggest threat to the Internet. A report from Symantec came to a similar conclusion, suggesting that home-based computers need to be more protected to eliminate the risk of producing botnets.