In recent years two things have become clear: first, the fight against malware is essentially unwinnable, and second, there is a way forward. Production and distribution of malware has become a business energized by powerful economic forces. The defenders are at a severe disadvantage and are losing the fight. We should look to new models and new ways of thinking to help organize our work in this area. An attractive domain to look at for new models is the biological one, in which organisms live in dynamic tension with their own malware.