Formal Specification for Fast Automatic IDS Training

A characterization of the behavior of an application is fundamental for the anomaly-based intrusion detection. This paper illustrates a methodology for the synthesis of the behavior of an application program in terms of the set of system calls invoked by the program. The methodology is completely automated, with the exception of the description of the high level specification of the application program, which is demanded to the system analyst. The technology employed (VSP/CVS) for such synthesis minimizes the efforts required to code the specification of the application. The methodology is completely independent from the intrusion detection tool adopted, and appears suitable to derive the expected behavior of a secure WEB server that can effectively support the increasing request of security that affects the ecommerce. As a case study, the methodology is applied to the Post Office Protocol, the ipop3d daemon.