The Outsider Interruption Algorithm

The Outsider Analysis (Outsider) module is part of the Analytic System and Software for Evaluation of Safeguards and Security (ASSESS). Outsider and the ASSESS Facility Descriptor (Facility) module together supersede the Systematic Analysis of Vulnerability to Intrusion (SAVI) PC software package. Outsider calculates P(I), the probability that outsiders are interrupted by security forces at a facility during an attack on the facility, and P(W), the probability of security system win. SAVI exhaustively examines every possible path to find the ten most vulnerable paths. Exhaustive search is adequate if the number of paths to examine is small, but moderately complex facilities can have millions of paths, making exhaustive search too slow for practical purposes. Outsider has two new algorithms that generate paths in order of vulnerability, finishing in a fraction of the time required by SAVI. The new Outsider algorithms make containment analysis easier for analysts than ever before. We describe the new algorithms and show how much better they perform than the SAVI exhaustive search algorithm.