Cryptocurrency platform Binance said Friday it was working to resolve a “complex attack” that affected around $6.3 billion in funds, in what is thought to be the biggest ever crypto heist, with investigators pointing to hackers linked to North Korea.

Blockchain investigation firm TRM Labs said it had “high confidence” that the attack was orchestrated by a North Korea-affiliated group called TraderTraitor, the same group blamed for the $1.5 billion theft from the Bybit platform in February last year.

Another analytics firm, Elliptic, also attributed the attack to North Korea-linked hackers, according to industry outlet CoinDesk.

TraderTraitor is believed to be part of Lazarus Group, which gained notoriety in 2014 when…