Data mining techniques, while allowing the individuals to extract hidden knowledge on one
hand, introduce a number of privacy threats on the other hand. In this paper, we study some of these
issues along with a detailed discussion on the applications of various data mining techniques for
providing security. An efficient classification technique when used properly, would allow an user to
differentiate between a phishing website and a normal website, to classify the users as normal users
and criminals based on their activities on Social networks (Crime Profiling) and to prevent users from
executing malicious codes by labelling them as malicious. The most important applications of Data
mining is the detection of intrusions, where different Data mining techniques can be applied to
effectively detect an intrusion and report in real time so that necessary actions are taken to thwart the
attempts of the intruder