Cross-chain protocol Multichain tweeted on Thursday that one white-hat hacker returned 259 ether, worth $813,000.
Multichain said three hackers stole a total of 602 ether ($1.9 million). The chief technology officer of crypto wallet ZenGo, Tal Be'ery, told CoinDesk that one attacker stole at least 450 ether, and that the total funds stolen were around $3 million.
The hacker who returned the funds kept $150,000, Be'ery said. The CTO found that other than the two main hackers, there were also some smaller players who exploited the vulnerability.
The protocol, which was formerly known as Anyswap, told users on Monday to remove approvals for six tokens to protect their funds from a security vulnerability.
Hackers were able to exploit the vulnerability and steal over $3 million in cryptos, according to a report.