Towards Scalable Computer Defenses

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We seem to be losing the battle of computer security. Despite increasing investments in software security on all sides, attackers are still able to bypass defenses seemingly at will. The situation is so bad that large network administrators must assume that their networks have already been infiltrated no matter how much effort they put in to their defenses. We assert that the key reason for this seemingly hopeless situation is that attacks are scalable while computer defenses are not. Attackers can make fixed-cost investments in attack development (e.g., finding a zero-day exploit, deveolping an exploit deployment mechanism) that can allow them to compromise millions of hosts. Defenders, however, can expend an unbounded amount of resources deploying firewalls, installing anti-malware software, running intrusion prevention systems, and manually auditing their software and configuration, only to find that their systems have still been compromised - assuming they are fortunate enough to even notice. We propose to study the theory and practice behind making scalable defenses. The key insight for building scalable defenses is that attacker work should scale with the population size of the defenders: attackers should be required to expend effort proportional to the number of hosts that are to be compromised. The key questions addressed in this research are first, how can we define defense scalability in terms of software architecture and economics, and to what extent are current defenses scalable. If this research is successful it should provide a foundation for building and evaluating a new generation of scalable computer defenses.