The reason the Obama administration is blaming North Korea for the cyberattack on Sony Pictures is that U.S. intelligence agents were already spying on the North Korean cyberspies and know what they were up to, The New York Times reported Sunday.
It said the U.S. National Security Agency had been hacking North Korean networks since 2010, and that the evidence it had gathered was critical in persuading U.S. President Barack Obama to accuse North Korea of ordering the Sony attack.
Obama said last month the United States would "respond proportionally" against North Korea for its cyberattack on Sony, "in a place and time and manner that we choose." Retaliation, in the form of new economic sanctions, has already begun.
It was the first time the United States has explicitly charged another government with mounting a cyberattack on U.S. targets, the Times said. North Korea has denied responsibility for the attack.
The United States has been implanting so-called network-mapping "beacons," surveillance software and, sometimes, destructive malware in the computer networks of foreign adversaries for about a decade, the report said, adding that the technology was crucial to the U.S. and Israeli attacks on Iran's nuclear program.
Sony pulled its $44 million screwball comedy "The Interview," which depicts a tabloid journalist who is asked to assassinate North Korean ruler Kim Jong-un, after North Korea said releasing it would be an "act of war" and terror threats were made against theaters showing the movie.
Sony later agreed to release the movie last month in some U.S. theaters and online, via video-on-demand services.