Cars enter and depart from Sony Pictures Entertainment studio lot in Culver City, Calif., Thursday, Dec. 18, 2014. Companies across the globe are on high alert to tighten up network security to avoid being the next company brought to its knees by hackers like those that executed the dramatic cyberattack against Sony Pictures Entertainment. The hack, which a U.S. official has said investigators believe is linked to North Korea, culminated in the cancellation of a Sony film, "The Interview," and ultimately could cost the movie studio hundreds of millions of dollars. (AP Photo/Damian Dovarganes) The Obama administration on Friday formally accused the North Korean government of being responsible for the devastating hacking attack against Sony Pictures Entertainment, providing the most detailed accounting to date of a hugely expensive break-in that could lead to a U.S. response.
The FBI said in a statement it has enough evidence to conclude that North Korea was behind the punishing breach, which resulted in the disclosure of tens of thousands of leaked emails and other materials.
"North Korea's actions were intended to inflict significant harm on a U.S. business and suppress the right of American citizens to express themselves. Such acts of intimidation fall outside the bounds of acceptable state behavior," the statement said.
The FBI's statement cited, among other factors, technical similarities between the Sony break-in and past "malicious cyber activity" linked directly to North Korea, including a prior cyberattack against South Korean banks and media.
President Barack Obama is expected to face questions about the Sony hack at a year-end news conference with reporters later Friday.
The break-in escalated to terrorist threats against moviegoers that prompted Sony this week to cancel the Christmas release of the movie "The Interview." The film, a comedy starring Seth Rogen and James Franco, is about a plot to assassinate North Korea's leader, Kim Jong Un.
North Korea has denied being responsible but earlier this month referred to the cyberattack as a "righteous deed." A North Korean diplomat to the United Nations, Kim Un Chol, declined to comment Friday about the FBI's accusations.
Obama administration officials had until Friday declined to openly blame North Korea but had said they were weighing various options for a response. The statement Friday did not reveal what options were being considered but did say the government would "impose costs and consequences."
It's not immediately clear what action, if any, the government will take. Bringing the shadowy hackers to justice appears a distant prospect. A U.S. cyberretaliation against North Korea would risk a dangerous escalation. And North Korea is already targeted by a raft of sanctions over its nuclear weapons program.
The FBI did not indicate whether it has identified any individual hackers who might be culpable. In May, the Justice Department indicted five Chinese military officers accused of vast cyberespionage against American corporate interests, but none of those defendants has yet to set foot in an American courtroom.