Colonel Blotto in the Phishing War

Phishing exhibits characteristics of asymmetric conflict and guerrilla warfare. Phishing sites, upon detection, are subject to removal by takedown specialists. In response, phishers create large numbers of new phishing attacks to evade detection and stretch the resources of the defenders. We propose the Colonel Blotto Phishing (CBP) game, a twostage Colonel Blotto game with endogenous dimensionality and detection probability. We find that the optimal number of new phishes to create, from the attacker’s perspective, is influenced by the degree of resource asymmetry, the cost of new phishes, and the probability of detection. Counter-intuitively, we find that it is the less resourceful attacker who would create more phishing attacks in equilibrium. And depending on the detection probability, an attacker will vary his strategies to either create even more phishes, or to focus on raising his resources to increase the chance he will extend the lifetime of his phishes. We discuss the implications to anti-phishing strategies and point out that the game is also applicable to web security problems more generally.