A botnet is a network of computers which are under the control of the malicious controller. Each component of this system is referred to as a bot. A bot comes in operation when a computer is infected with malware, owing to which it comes under the control of third-party controllers. Bot computers can operate in remote directions without any knowledge to its owner. The controllers which operate these bots are referred to as botmasters. A botnet is used majorly in an illegal way, so as to gather personal information of the owner or any other associated user. Although, detection of botnet attacks is difficult as the malware is designed in such a way that they can operate without the knowledge of the owner. However, there are few key signs which can give a hint of a possible botnet attack on the computer. These include slow computing speed and high CPU usage and excessive unexpected popups among various others.