METHOD AND APPARATUS FOR ANALYZING INFORMATION SYSTEMS USING STORED TREE DATABASE STRUCTURES

A computer-implemented method and apparatus electronically represent and quantify the security of a system as a logical tree structure including leaf nodes representing attacks against the system and intermediate nodes representing various logical combinations of attacks necessary to mount a successful overall attack. An indication of the overall security of the system is quantified in a value of a root node of the tree. The values of the various nodes can be Boolean or continuous, representing simple binary security attributes such as feasible/infeasible or more complicated attributes such as cost, time or probability. The nodes' attributes and values can also represent defenses as well as attacks. The attack trees can be used to calculate the cost, time or probability of an attack to list the security assumptions of a system, to compare competing systems, to evaluate system modifications, to perform security subsystem analysis, to allocate a security budget, and for many other uses.