The New York Times reports that a secret White House legal review has cleared the way for preemptive cyber attacks if the president determines there is credible evidence of a pending attack. Officials who had been involved in the review told The Times' David Sanger and Thom Shanker that the new rules give the president "broad power" to order computer-based attacks on adversaries that disrupt or destroy their systems, without requiring a declaration of war from Congress. The rules also govern how intelligence agencies can monitor networks for early warnings of imminent attacks, and when the Department of Defense can become involved in dealing with domestic network-based attacks.

The rules will leave the Department of Homeland Security and FBI responsible for defending US government and commercial networks from attack up to a certain threshold—the exact nature of which is being kept secret—after which the Department of Defense would become involved. The DoD would only be allowed to take offensive action with direct presidential approval.

News of the ruling comes on the heels of reports of major computer-based attacks on the New York Times, the Wall Street Journal, and the Washington Post, all of which were attributed to state-sponsored hackers in China.

So far, the only software-based attack that has been attributed to the US (though never officially acknowledged by the US government) has been the Stuxnet virus, which was reportedly codeveloped with Israeli intelligence to disable production equipment in an Iranian nuclear facility. Other sophisticated malware attacks, such as Flame, Duqu, and Gauss have not been definitively tied to the US, but analysts at Kaspersky Labs and other antivirus and network security firms have described them as "state-sponsored."