Achieving security has become one of the most critical factors as more and more sensitive data and information is being maintained and manipulated online. Intrusion Detection System (IDS) is one of the most popular methods which is used to detect malicious activities and maintains the security of the system. IDS can use either anomaly based approach or misuse based approach. In order to detect the malicious activities large amount of data is analyzed. For analyzing data using data mining techniques are best way to achieve the required objective.