Abstract: Botnets are one of the most serious and widespread
cyber threats. Today botnets have been facilitating many
cybercrimes, especially financial, top secret thefts. Botnets can be
available for lease in the market and are utilized by the
cybercriminals to launch massive attacks like DDoS, click fraud,
phishing attacks etc., Several large institutions, hospitals, banks,
government organizations and many social networks such as twitter,
facebook etc., became the target of the botmasters. Recently,
noteworthy researches have been carried out to detect bot, C&C
channels, botnet and botmasters. Using many sophisticated
technologies, botmasters made botnet a titan of the cyber world.
Innumerable challenges have been put forth by the botmasters to the
researchers in the detection of botnet. In this paper we present a
survey of different types of botnet C&C channels and also provide a
comparison of various botnet categories. Finally we hope that our
survey will create awareness for forthcoming botnet research
endeavors.