Defense Secretary Leon Panetta has hinted at U.S. willingness to fight fire with fire  regarding cyber-attacks. In a speech to the business community in New York, he claimed that American infrastructure systems were being targeted by "foreign actors" in an attempt to get control of utilities such as the water system or the power grid.
A pre-emptive strike would happen through a presidential executive order, he claimed, citing political gridlock and under-investment in cyber security by private firms. "If we detect an imminent threat of attack that will cause significant physical destruction in the United States or kill American citizens, we need to have the option to take action against those who would kill us," Mr. Panetta said.
As to what form the strike would take there was, unsurprisingly, no clue, but the USDoD could send out trojans to be activated later, rather like the Stuxnet  worm.
There was plenty of scaremongering in the speech, with the former CIA head talking about "derailing passenger trains or trains loaded with lethal chemicals." The timing of Mr. Panetta's speech is interesting, to say the least. It comes in the same week that a Congress Committee accused two Chinese tech firms of being a national security risk .