There are some real dangers. "Hackers can try to break into research communications between weapons labs and universities," says Thompson, "and they can mess up a lot of traffic pertaining to such support activities as paychecks, logistics, transportation and spare parts." But, he stresses, cyber-spies cannot penetrate the heart of the nation's defenses -- because the Pentagon keeps the good stuff offline. "The Pentagon's key military networks are not on the Internet," says Thompson, "and they are not linked to the Internet." So while the hackers may succeed at making life difficult for the military, they cannot compromise national security.
"You can basically say we are at war," Representative Curtis Weldon told CNN this week following closed-door hearings he held to study recent waves of cyber-attacks on the Pentagon's computer networks. Well, not quite. The hearings did reveal a new and "more systemic" pattern of assaults, says TIME Pentagon correspondent Mark Thompson, but nothing that should cause the nation to panic. "The Pentagon is simply learning that hacker probes are a cost of doing business over the Internet," he says. "These probes will continue to happen, and the military is just going to have to put up better cyber-guardrails."