This document summarizes research on using Markov chain models for anomaly detection in network intrusion detection systems. It first provides background on intrusion detection and different approaches. It then reviews several related works that use techniques like k-means clustering, decision trees, genetic algorithms, and Markov chains. The paper proposes using a k-means algorithm combined with a Markov chain model to detect attacks. The Markov chain model analyzes system state transitions over time to probabilistically model normal behavior and detect anomalies. The existing system has low detection and prevention rates. Future work could explore using eigenvectors and thresholds to improve performance.