A Suite of Metrics for Network Attack Graph Analytics

This chapter describes a suite of metrics for measuring enterprise-wide cybersecurity risk based on a model of multi-step attack vulnerability (attack graphs). The attack graphs are computed through topological vulnerability analysis, which considers the interactions of network topology, firewall effects, and host vulnerabilities. Our metrics are normalized so that metric values can be compared meaningfully across enterprises. To support evaluations at higher levels of abstraction, we define family groups of related metrics, combining individual scores into family scores, and combining family scores into an overall enterprise network score. The Victimization metrics family measures key attributes of inherent risk (existence, exploitability, and impact) over all network vulnerabilities. The Size family is an indication of the relative size of the vulnerability attack graph. The Containment family measures risk in terms of minimizing vulnerability exposure across security protection boundaries. The Topology family measures risk through graph theoretic properties (connectivity, cycles, and depth) of the attack graph. We display these metrics (at the individual, family, and overall levels) in interactive visualizations, showing multiple metrics trends over time.