With the growth of the Internet and the number of users who are well acquainted to the Internet have also grown these user either use, misuse or try to damage (it can be update, modify, delete, etc.) such information (here information is basically personal, private details or banking details of a user). These users can either have intentional or non-intentional motive of doing so. This paper consist of a study of the various types of hacker, the various kinds of cybercrimes practices or faced now-a-days and authorities that check and take measures to prevent any of these cybercrimes.