Sensing Attacks in Computers Networks with Hidden Markov Models

摘要

In this work, we propose an Intrusion Detection model for computer newtorks based on Hidden Markov Models. While stateful techniques are widely used to detect intrusion at the operating system level, by tracing the sequences of system calls, this issue has been rarely researched for the analysis of network traffic. The proposed model aims at detecting intrusions by analysing the sequences of commands that flow between hosts in a network for a particular service (e.g., an ftp session). First the system must be trained in order to learn the typical sequences of commands related to innocuous connections. Then, intrusion detection is performed by indentifying anomalous sequences. To harden the proposed system, we propose some techniques to combine HMM. Reported results attained on the traffic acquired from a European ISP shows the effectiveness of the proposed approach.