An intrusion detection system monitors a network or a collection of systems for malicious activity or policy violations. Any malicious activity or violation caught is stopped or reported. In this chapter, we will design and implement several intrusion detection systems using machine learning. We will begin with the classical problem of detecting spam email. We will then move on to classifying malicious URLs. We will take a brief detour to explain how to capture network traffic, so that we may tackle more challenging network problems, such as botnet and DDoS detection. We will construct a classifier for insider threats. Finally, we will address the example-dependent, cost-sensitive, radically imbalanced, and challenging problem of credit card fraud.
This chapter contains the following recipes:
- Spam filtering using machine learning
- Phishing URL detection...