Abstract: Bot is a malware installed in a network device. The word bot was derived from ‘robot’ an automated process used to interact with other services. Botnet is a collection of bots (devises) receiving and responding to commands from bot master. Bot master takes control of bots to perpetrate various activities such as DDoS attacks information theft (username, passwords, financial information), spam camping using emails, acting as other identity and causing network congestion. The attacked network device may not be aware of the bot, bot will be running in the background. Bot will perform the activities instructed by bot master. As per the surveys around 25% of the effected network devices are due to botnet. The attackers are tending towards botnets because it is less expensive and easy to propagate the attack. Symantec botnet intended to advertisement able to create 10,000 bots with just us $15. The intention of this survey is to look at the botnet, architecture and its impact on cyber world. It was getting developed. We want to bring all these details in one study.