A decision engine includes: a genetic algorithm framework including a knowledge base of standard configurations, a candidate selector generator and a selector to select a candidate configuration from a plurality of preferred standard configurations in response to the candidate selector generator; a parallelized reasoning framework including an attack surface reasoning algorithm module to compute the security and cost tradeoffs of an attack surface associated with each candidate configuration; and a user interface framework including a web service engine where users can interact and provide feedback on direction of an evolution used in a genetic algorithm search for evolving defenses.