Domain names drive the ubiquitous use of the Internet. Criminals and adversaries also use domain names for their enterprise. Defenders compete to remove or block such malicious domains. This is a complicated space on the Internet to measure comprehensively, as the malicious actors attempt to hide, the defenders do not like to share data or methods, and what data is public is not consistently formatted. This paper derives an ad hoc model of this competition on large, decentralized networks using a modification of Lanchester's equations for combat. The model is applied to what is known of the current state of malicious domain activity on the Internet. The model aligns with currently published research, and provides a more comprehensive description of possible strategies and limitations based on the general dynamics of the model.
When taken with the economic realities and physical laws to which the Internet is bound, the model demonstrates that the current approach to removing malicious domain names is unsustainable and destined for obsolescence. However, there are technical, policy, and legal modifications to the current approach that would be effective, such as preemptively populating watch lists, limits on a registrant's registrations, and international cooperation. The results indicate that the defenders should not expect to eliminate or significantly reduce malicious domain name usage without employing new digital tactics and deploying new rules in the physical world.