These spies are already launching 90,000 attacks a year just against U.S. Defense Department computers, according to a senior FBI analyst familiar with the contents of the report, making news Tuesday that the Chinese government may have hacked the email accountings of human-rights activists, prompting Google to consider withdrawing from that country, seem like child’s play…

The FBI report concludes that a massive Chinese cyberattack could “be in the magnitude of a weapon of mass destruction,” says the analyst, who requested anonymity because he was not authorized to speak about it, adding that it would do substantial damage to the American economy, telecommunications, electric power grid, and military preparedness…

One of China’s most effective weapons, according to the FBI report, is a continuation of what Pentagon security investigators originally dubbed Titan Rain; it is a Chinese scanner program that probes national defense and high-tech industrial computer networks thousands of times a minute looking for vulnerabilities. The Chinese military hackers, the FBI analyst told me, enter without any keystroke errors, leave no digital fingerprints, and create a clean backdoor exit in under 20 minutes, feats considered capable only for a military or civilian spy agency of only a few governments.