Ten days after the U.S. government concluded that North Korea was behind the attack on Sony Pictures Entertainment, the image of events that led to the theft of tens of terabytes of data has become more blurry.
On Monday, security firm Norse Corp. briefed the Federal Bureau of Investigation on its evidence that an insider, not North Korean agents, caused the massive data leak and handed over access credentials and other data to independent outside hackers. The company cited its analysis of the malware and command-and-control infrastructure as well as logs from underground forums and Internet chat channels and concluded that one or more disgruntled employees worked with at least two other attackers to steal the data and attempt to blackmail the company.
"We see lots of data that supports that hypothesis," Kurt R. Stammberger, senior vice president at Norse, told eWEEK. "We don't see data points anywhere that say this attack was supported by, initiated by or masterminded by the government of North Korea."
Norse is the latest company to come out with alternate theories of who may have hacked Sony Pictures Entertainment and the reasons behind the attack. On Dec. 19, the FBI and President Obama both said that the U.S. government believed that North Korea conducted or sponsored the attack. Yet the scant evidence the FBI shared has not satisfied security experts.
The following week, a number of media outlets, such as Wired, questioned the conclusion. In addition, security intelligence firm Taia Global, used linguistic analysis on the English language messages sent to Sony by the attackers to conclude that the attackers were most likely Russian. "Our preliminary results show that Sony's attackers were most likely Russian, possibly but not likely Korean and definitely not Mandarin Chinese or German," the company stated in a blog post.
Even the Guardians of Peace, the until-recently unheard-of group claiming responsibility for the Sony Pictures attack has denied they are working with or for North Korea. "We are not Korean," they tweeted.
The analysis report, a copy of which Norse declined to provide to eWEEK, focused on both technical aspects of the attack that did not fit with the theory of a nation-state operation and intelligence from underground forums that appeared to identify some of the pre-attack communications between a disgruntled Sony ex-employee and a group of hackers, Stammberger said.
On the technical side, both the malware and the command-and-control infrastructure had attributes that did not fit with the U.S. government's theory that North Korea instigated the attack. The customized malware appeared to have been programmed with knowledge of Sony Picture's infrastructure; the programmers knew where to find critical assets on the Sony Pictures Entertainment network, including Exchange servers, authentication servers and file storage, according to Stammberger.
Pre-attack communications caught by Norse's data-collection network identified conversations that were likely between a disgruntled Sony Pictures employee, or former employee, and known hackers.
"We have identified specific individuals, [and] we have a non-trivial amount of data connecting them to that activity," Stammberger said. "Whether that rises to the level of proof is up to the FBI."
Post-attack communications with Sony also do not fit the North Korean meme, he said.
"The initial demands that were made in the first few days after the attack were bread-and-butter extortion demands," Stammberger said. "They said nothing about the movie ["The Interview"]; they said nothing about the political agenda of any nation or group. It was, 'You wronged us, and you need to give us money or horrible things will happen.'"