Day by day the number of different attacks are increasing. Attackers or hackers always try to break the security policies. We have to face different types of intrusions. To keep our system or network safe from the attackers, we have to think about Intrusion Detection System. This book presents a brief idea on intrusion and intrusion detection system. Here, useful multivariate statistical technique has been used to detect intrusion. Here, we deal with hardware profile data. Our approach computes a standard detection rate and negligible false alarm rate. The entire process to detect intrusion, we have shown a clear flowchart for understanding.