U.S. is the only country ever to launch an actual cyberwar

"The United States is, by far, the world’s most aggressive nation when it comes to cyberspying and cyberwarfare. The National Security Agency has been eavesdropping on foreign cities, politicians, elections and entire countries since it first turned on its receivers in 1952." "In fact, the United States is the only country ever to launch an actual cyberwar -- when the Obama administration used a cyberattack to destroy thousands of centrifuges, used for nuclear enrichment, in Iran. This was an illegal act of war, according to the Defense Department’s own definition." (thanks Amir)