Hackers behind the record-breaking Binance heist spent weeks masquerading as recruiters and fake executives, eventually convincing an engineer to download malicious software onto a work computer as part of a larger-scale ruse, the company said Tuesday.

Binance said the ploy included two rounds of interviews, with a supposed human resources representative conducting the first interview and sharing social media information to gain the programmer’s trust. A second person, posing as the CEO of a fake company, later persuaded the engineer to download a file containing malware under the guise of an interview assessment.

“This was a complex attack,” Binance co-CEO Richard Teng said on social media Monday. “The…