North Korean cryptocurrency thieves tricked a Binance software engineer into downloading malware onto their work-issued computer during a fake job interview process before last week’s record-breaking $6.3 billion heist.

In an incident report published on Tuesday, the cryptocurrency exchange said several techniques - including social engineering via fake job interviews, malware downloads, compromised internal AI tooling, endpoint takeover, and an “advanced transaction-authorization method” - led to the October 29 security breach.

“Our current investigation indicates that this was a sophisticated, multi-stage campaign,” the incident report said. “It was not a single isolated breach or a simple phishing incident.”

Over the weekend, the FBI attributed the theft to TraderTraitor, a North Korean hacking operation linked to Lazarus Group, known for combining espionage with massive cryptocurrency heists. The Pyongyang-backed crew is also highly adept at job market scams - both posing as IT workers, who are then hired by Western companies, and as potential employers to lure software engineers into downloading malware and infecting corporate devices.