In this chapter, we will provide a brief overview of network security and introduce essential concepts of intrusion detection and prevention and review their basic principles and guidelines. Then, we will discuss statistical approaches in practice as well as statistical opportunities, roles, and challenges in network security. Network security has become a very popular topic. A simple Google search based on the keyword “network security” showed 2.2 million items on February 29, 2008. Network security aims to protect the entire infrastructure of a computer network and its corresponding services from unauthorized access. The two key elements of network security are risk assessment and risk management. There are several fundamental components in network security: (1) security-specific infrastructures, such as hardware- and software-based firewalls and physical security approaches, (2) security polices, which include security protocols, users’ authentications, authorizations, access controls, information integrity and confidentiality, (3) detection of malicious programs, including anti-viruses, worms, or Trojan horses, and spyware or malware, and (4) intrusion detection and prevention, which encompasses network traffic surveillance and analyzing and profiling user behavior. Since the topic of network security links a great number of research areas and disciplines, we will focus on the component of intrusion detection and prevention in this book. Readers who are interested in other components or want to gain more detailed information on the entire topic may refer to Smedinghoff (1996), Curtin (1997), Garfinkel and Spafford (1997), McClure, Scambray, and Kurtz, (1999), Strebe and Perkins (2000), Bishop (2003), Maiwald (2003), Stallings (2003), Lazarevic, Ertoz, Kumar, Ozgur, & Srivastava, (2003), Bragg, Rhodes-Ousley, Strassberg (2004), McNab (2007), and Dasarathy (2008). For wireless network security, Vacca (2006) provides an essential step-by-step guide that explains the wireless-specific security challenges and tasks, and for mobile phone related intrusion detection refer to Isohara, Takemori & Sasase (2008). Finally, for an overall introduction on network security, including key tools and technologies used to secure network access, refer to Network Security Principles and Practices by Malik (2003) and Network Security Fundamentals by Laet & Schauwers (2005).
