Botnets come under the category of such inventions and become a source of much distress for the computer user. Botnets pose different kinds of threats like denial of service, spamming, click fraud etc. Several techniques and mechanisms have been adapted to enhance the security measures of networks and avoid any damage by botnets.
‘Bot’ is defined as a single computer that possesses the malicious program to make it a part of a wider network of similar computer systems, which is known as ‘Botnet’. Botnets are defined as an autonomous set of programs that perform functions without the aid of any user. They are either controlled by one system or multiple systems, which are known as the botmaster. A distributed nature of botnets involves a set of distributed computers that communicate with each other over the internet and perform some tasks together (Banday et al, 2009). The communication between the bots and the botmaster can be a direct link but such communication can make the botmaster identifiable in the network. Therefore, such direct links are not used. On the contrary, command languages and control protocols (C&C) are used to manage the bots remotely (Banday et al, 2009). These set of programs were initially developed to automate tasks on a set of machines to minimize the need of the presence of a person and to enhance communication and resource sharing. But the concept of their usage changed drastically when they started being used for malicious purposes. Botnets started being developed for the purpose of financial gains and recognition. The hacker’s scale of goodness of a botnet is the degree of damage that it is able to cause.
Intruders and spammers can install the software (required for intrusion) in a number of ways. The user might not even be aware of the vulnerability of his system and may become a bot in the network of similarly compromised computers. The first step in this unpleasant activity is the identification of a computer on the