The best defense against cyberattacks on U.S. military, civil and commercial networks is to go on the offensive, said Marine Gen. James Cartwright, commander of the Strategic Command (Stratcom), said March 21 in testimony to the House Armed Services Committee.

“History teaches us that a purely defensive posture poses significant risks,” Cartwright told the committee. He added that if “we apply the principle of warfare to the cyberdomain, as we do to sea, air and land, we realize the defense of the nation is better served by capabilities enabling us to take the fight to our adversaries, when necessary, to deter actions detrimental to our interests.”

Cartwright said U.S. adversaries in cyberspace include other countries, terrorists and criminals who operate behind what he described as technical, legal and international screens, and he said that “if we are to take the fight to our adversaries, we will need Congress’ help finding solutions to penetrate these screens.”

Stratcom is the lead command within the Defense Department and it is charged with planning and directing cyberspace defense. It also manages the U.S. nuclear deterrent forces.

The Stratcom commander told the committee that the United States is under widespread, daily attacks in cyberspace. He added that  the country lacks dominance in the cyberdomain and that it could become “increasingly vulnerable if we do not fundamentally change how we view this battle space.”

Cartwright said U.S. cyberspace adversaries have potentially different motives – financial, political or military – and “threaten the freedom to embrace the opportunity offered by a globally connected, flattened world.”

He added that the magnitude of cost in terms of dollars dedicated to cyberdefense measures, lost intellectual capital and fraud that results from cyberattacks cannot be overestimated, “making these attacks a matter of great national interest.”

Stratcom continues to make progress in developing information operations capabilities into core military capabilities, Cartwright said, providing joint force commanders with the capability to gain and maintain information advantage over U.S. cyberspace adversaries.