FBI agents investigating the computer hacking of Sony Pictures were briefed Monday by representatives of a cyber-intelligence security firm that says a company insider and not North Korea was culpable,
Politico reports.
Researchers with
Norse, a technology security company, say their own investigation points to some combination of a disgruntled employee and hackers with piracy groups.
Kurt Stammberger, a senior vice president with Norse, said the fact that the FBI announced its conclusion so quickly after the initial hack was revealed created suspicion that the bureau had jumped to a conclusion.
"It's really hard to pin this on anyone within days of the attack," he said.
Stammberger said last week that he had identified
the person behind the leak as a woman named "Lena," who worked for Sony for 10 years before leaving in May.
Sony, he added, "was essentially nuked from inside."
Stammberger said Monday that the FBI was "very grateful for our data and assistance."
But the FBI emphasized that it stands behind its assessment that Pyongyang is to blame, adding that the evidence doesn't support any other explanation.
"The FBI has concluded the government of North Korea is responsible for the theft and destruction of data on the network of Sony Pictures Entertainment. Attribution to North Korea is based on intelligence from the FBI, the U.S. intelligence community, DHS, foreign partners and the private sector," a bureau spokeswoman said.
She added that "there is no credible information to indicate that any other individual is responsible for this cyber-incident."
Another alternative theory is that the perpetrators of the attack may have been Russians. A report issued by the research firm
Taia Global said that linguistic analysis of the messages thought to have been sent by hackers suggests they spoke Russian rather than Korean.
Marc Rogers, chief of security for the hacker group DEF CON, said he remained skeptical of the FBI's assessment that North Korea was responsible. Rogers said the bureau appeared to be reliant on IP addresses that are easy to hijack, Politico reports.
Even so, skeptics "leave open the possibility that the government has other intelligence supporting the idea that it's North Korea," which outside experts lack access to.