A Sense of Self for Unix Processes
A method for anomaly detection is introduced in which "normal" is defined by short-range correlations in a process ' system calls. Initial experiments suggest that the definition is stable during normal behavior for standard UNIX programs. Further, it is able to detect several common intrusions involving sendmail and lpr. This work is part of a research program aimed at building computer security systems that incorporate the mechanisms and algorithms used by natural immune systems. 1 Introduction We are interested in developing computer security methods that are based on the way natural immune systems distinguish self from other. Such "artificial immune systems" would have richer notions of identity and protection than those afforded by current operating systems, and they could provide a layer of general-purpose protection to augment current computer security systems. An important prerequisite of such a system is an appropriate definition of self, which is the subject of this paper