REUTERS/Larry Downing U.S. President Barack Obama answers a question after his end of the year press conference in the briefing room of the White House in Washington, December 19, 2014.

The November hack of Sony "resulted in the destruction of about three-quarters of the computers and servers at the studio’s main operations," David Sanger and Michael Schmidt reported this weekend in the New York Times.

American officials had previously concluded that North Korea was “centrally involved,” and intelligence officials told the Times that the US intelligence community "concluded that the cyberattack was both state-sponsored and far more destructive than any seen before on American soil."

President Barack Obama has publicly blamed North Korea, and on Friday the U.S. Treasury imposed sanctions on 10 senior North Korean officials and the intelligence agency deemed to be behind “many of North Korea’s major cyberoperations.”

The Times notes that skeptics, including several cybersecurity firms, argue that the president " had been misled by American intelligence agencies that were too eager to blame a longtime adversary and allowed themselves to be duped by ingenious hackers skilled at hiding their tracks."

The evidence against Pyongyang, much of which is classified, is reportedly substantial. Shane Harris of The Daily Beast, citing sources familiar with the investigation, reports that "the most damning evidence against the Sony hackers was obtained in a secret, and years earlier, during previous intelligence-gathering efforts. "

REUTERS/Mario Anzuoni An entrance gate to Sony Pictures Studios is pictured in Culver City, California December 19, 2014.

The Times adds that "Obama’s critics do not have a consistent explanation of who might have been culpable." The notion that a disgruntled former employee masterminded the huge hack has been denied by CEO of Sony Entertainment Michael Lynton.

Others assert that it was outside hacking groups using 'The Interview' — a crude comedy in which two television hosts travel to North Korea and assassinate Supreme Leader Kim Jong-Un — as cover. In June, North Korea called the comedy " the most blatant act of terrorism" and vowed that "a merciless counter-measure will be taken " if the Obama administration allowed the film's release.

The Sony hack is the second major attack in which hackers targeted American corporate infrastructure on a large scale with the primary goal of destroying it (as opposed to stealing from it or spying on it).

Dozens of terabytes of information was taken, revealing information including scripts, unreleased movies, actor compensation, and off-the-cuff conversations among high-level Sony executives.