The US military's computer networks are so infested with foreign spies that trying to fight them might not be worth the trouble, security experts say. Instead, the focus should be on protecting the data — such as information on nuclear weapons — that's in those networks. That's according to a group of experts from the US National Security Agency, who claim that future cybersecurity efforts should just "assume that the adversary is in our networks." According to Dr Kaigham Gabriel, head of the Defence Advanced Research Projects Agency, the current technique of defending against attacks is similar to treading water in the middle of the ocean — it's simply futile. The Department of Defense currently watches over around 15,000 networks, but with limited resources — made worse by the government offering low-paying cybersecurity jobs with few promotions — a more focused approach based on protecting data should make the department more effective.