The FBI attributed the Sony breach to North Korea, which many security experts initially questioned, asking to see the technical indicators used to arrive at that conclusion.
The Wall Street Journal, citing officials familiar with the case, reported on March 22 that prosecutors also believe Chinese middlemen helped Pyongyang plunder the Bangladesh bank's funds in February 2016. These individuals, or businesses, could reportedly face sanctions.
Prosecutors are reportedly focusing on the North Korea connection because the bank cybertheft featured a rare piece of code that was also used in the hack of Sony Pictures that took place in late 2014. That's the equivalent of one-fortieth of impoverished North Korea's 2014 estimated gross domestic product, or one-quarter of the $4 billion stored in overseas bank accounts that South Korean intelligence agencies estimate leader Kim Jong-un inherited from his father, Kim Jong-il.
"The whole security community has said that the attack tools and techniques used in Sony are the same ones used in Bangladesh", said Eric Chien, an engineer with Symantec Corp., the Journal reported. "That is a big deal in my opinion".
"If that attribution is true, if that linkage from Sony actors to Bangladeshi bank actors is accurate, that means a nation state is robbing banks", Ledgett said.
The network, called the Society for Worldwide Interbank Financial Telecommunication, or SWIFT, has since been targeted by hackers trying to infiltrate other financial institutions. After gaining access to the SWIFT credentials of the bank, the attackers were able to send messages to the New York Fed requesting the release of funds.
Last week, SWIFT said it planned to cut off the remaining North Korean banks still connected to its system as concerns about the country's nuclear program and missile tests grow.
The office of the United States attorney in Los Angeles had been examining the extent to which the bold heist in February 2016 had been aided by the North Korean government, according to a person briefed on the investigation who was not authorised to speak publicly, The New York Times reported.