In information security, intrusion detection is the act of detecting actions that attempt to compromise the integrity, confidentiality, or availability of a resource. Intrusion detection does not, in general, include prevention of intrusions. This paper is concentrating on data mining techniques that are being used for such purposes. Advantages and disadvantages of these techniques have been discussed in this paper. Modern intrusion detection applications facing complex problems. These applications has to be require extensible, reliable, easy to manage, and have low maintenance cost.