In a worrying sign of the hidden vulnerability of supposedly secure cryptocurrency, cyber criminals have stolen some $600m in one of the largest such thefts.
Blockchain site Poly Network said hackers had exploited a vulnerability in its system and taken thousands of digital tokens such as Ether.
About $267m of Ether currency has been taken, $252m of Binance coins and roughly $85 million in USDC tokens.
The hack appears to be one of the biggest in decentralised finance, or DeFi, peer-to-peer cryptocurrency platforms that allow transactions without traditional gatekeepers such as banks or exchanges.
Poly Network allows users to swap tokens across different blockchains.
The stolen funds amount to more than the criminal losses registered by the entire DeFi sector from January to July of a record $474 million, according to a report from crypto intelligence company CipherTrace published on Tuesday.
In a letter posted on Twitter, it urged the thieves to “establish communication and return the hacked assets”.
In its letter Poly Network said: “The amount of money you have hacked is one of the biggest in defi [decentralised finance] history. Law enforcement in any country will regard this as a major economic crime and you will be pursued.”
It added that “the money you stole are [sic] from tens of thousands of crypto community members, hence the people.”
Poly Network said a preliminary investigation found a hacker exploited a “vulnerability between contract calls”.
It urged various exchanges to block deposits of the coins, after millions of dollars in tokens were transferred to separate cryptocurrency wallets.