In recent weeks, some large U.S. financial institutions were hit by ‘denial of service’ attacks on their websites. Two months ago, the Saudi Arabian state oil company ARAMCO and RasGas of Qatar were attacked by a computer “wiper” virus called “shamoon.” Crucial system files were replaced with an image of a burning U.S. flag. Real data on more than thirty thousand computers was overwritten with “garbage data,” rendering them useless. American intelligence officials increasingly suspect Iran was behind these attacks. Last week, Defense Secretary Leon Panetta called this a pre-nine-eleven moment for cyberdefense. James Lewis of the Center for Strategic and International Studies, Thom Shanker of the New York Times and Greg Nojeim of the Center for Democracy and Technology join Diane for a discussion of the growing threat of cyberwarfare.