Recent Advances in Intrusion Detection

Volume 1907 of the series Lecture Notes in Computer Science pp 110-129


Intrusion Detection Using Variable-Length Audit Trail Patterns

  • Andreas WespiAffiliated withIBM Research, Zurich Research Laboratory
  • , Marc DacierAffiliated withIBM Research, Zurich Research Laboratory
  • , Hervé DebarAffiliated withIBM Research, Zurich Research Laboratory

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Audit trail patterns generated on behalf of a Unix process can be used to model the process behavior. Most of the approaches proposed so far use a table of fixed-length patterns to represent the process model. However, variable-length patterns seem to be more naturally suited to model the process behavior, but they are also more difficult to construct. In this paper, we present a novel technique to build a table of variable-length patterns. This technique is based on Teiresias, an algorithm initially developed for discovering rigid patterns in unaligned biological sequences. We evaluate the quality of our technique in a testbed environment, and compare it with the intrusion-detection system proposed by Forrest et al. [8], which is based on fixed-length patterns. The results achieved with our novel method are significantly better than those obtained with the original method based on fixed-length patterns.


Intrusion detection Teiresias pattern discovery pattern matching variable-length patterns C2 audit trail functionality verification tests