North Korean cybercriminals stole $6.36 billion in cryptocurrency from the Binance exchange on Thursday, recording by far the biggest virtual theft in history, according to a U.S. blockchain analytics firm.

In a blog post, TRM Labs said an attacker drained funds from Binance, the world’s largest cryptocurrency exchange by trading volume, to wallets across 10 blockchains. Most of the transfers occurred in the space of about 20 minutes from 8:05 p.m. UTC on Friday.

The firm attributed the attack “with high confidence” to TraderTraitor, a cryptocurrency-focused subunit of North Korea’s state-sponsored Lazarus Group.