4. Conclusions and further work
The intelligent intrusion detection system outlined in this paper significantly improves upon the performance of signature based detection methods by utilising an artificial neural network classifier for the identification of shellcode patterns in network traffic. The ANN based classifier not only achieves perfect sensitivity on the test dataset (identifying all instances of shellcode), it also exhibits excellent precision (minimising the number of false positives identified). The performance of the proposed approach was then further evaluated with respect to the false positive rate by testing on an extremely large (400,000 samples) set of benign network traffic file content — where the proposed approach achieved a false positive rate of less than 2%. Minimising the false positive rate is a major concern for the application of network intrusion systems in the real-world, as high levels of false positives result in an extremely poor signalto-noise ratio and often render the system useless.
The research presented in this paper describes an offline approach to detecting shellcode patterns within data. Work is currently ongoing to integrate the approach proposed in this paper into online network intrusion detection systems and to test on real-time network data, with further real-time optimisations for live network traffic an active area of development. Another area identified for further work is the application of the intelligent approach to intrusion detection outlined here to other areas of network security such as the detection of cross-site scripting attacks and SQL injection attacks on web applications.