An Effective Approach for Stepping-Stone Intrusion Detection Using Packet Crossover

An effective approach for stepping-stone intrusion detection (SSID) is to estimate the length of a connection chain, which is referred to as the network-based detection approach. In this paper, we propose an effective network-based approach for SSID using packet crossover. Existing network-based approaches for SSID are either not effective, or not efficient as they require a large number of TCP packets to be captured and processed. Some other existing network-based approaches for SSID do not work effectively when the fluctuation of the packets’ RTTs is large and requires the length of a connection chain to be pre-determined, and thus these existing detection methods have very limited performance. Our proposed algorithm for SSID using packet crossover can effectively determine the length of a downstream connection chain without any pre-assumption about the length of a connection chain as well as not requiring a large number of TCP packets being captured and processed, and thus our proposed SSID algorithm is more efficient. Since the number of packet crossovers can be easily calculated, our proposed detection method is easy to use and implement. The effectiveness, correctness and efficiency of our proposed algorithm for SSID are verified through well-designed network experiments.