At least $600 million was taken off three chains in what appears to be the largest hack in the history of Decentralized Finance, or DeFi.
The Polygon network reported on Tuesday that information on Binance Chain, Ethereum, and the Polygon network had been removed as a result of the attack.
According to blockchain data, there was a theft of approximately $273 million in Ethereum, $85 million in USD Coin from the Polygon network, and $253 million in Binance Smart Chain.
According to Poly, wrapped Bitcoin, wrapped Ether, and renBTC were also used in the exploit.
Shortly after the hack broke, Chinese cybersecurity firm SlowMist announced that its analysts had identified the hacker's IP address, email address, and device fingerprint, but did not reveal any further details.
Using data from the Hoo exchange and other firms, the firm determined that Monero (XMR) was the hacker's initial funding source, but it was then switched to Binance Coin (BNB), Ether (ETH), and MATIC.
In combination with the flow of funds and multiple fingerprints, it appears that this was a long-planned, organized, and prepared attack," said SlowMist.
Among the strange messages posted by the hacker were three through Ethereum transactions. After not being able to move some tokens, Etherscan reported they may return some of the stolen funds.
The DAO asked the community to help them launder digital assets through Tornado, and they suggested the DAO decides where the tokens should go:
“I just saved the project if I had moved the remaining shitcoins! Was the money worth it or am I just considering returning some tokens or leaving them there?"
DeFi and the crypto community also stepped up to offer assistance and support. Jay Hao, CEO of OKEx, said that the exchange was watching how the coins were flowing and would make sure that the situation was managed.
Tether's CTO Paolo Ardoino noted that the company has frozen roughly $33 million in Tether from one of the affected addresses, while Binance's CEO said his company is coordinating with security partners to assist.
Poly Network was launched last year as a joint endeavor by Ontology, Neo, and Switcheo to create a platform for heterogeneous interoperability between blockchains, integrating the chains into a larger ecosystem. Tokens on different blockchains can be swapped using the protocol.
Weirdly, the hackers returned some of those funds Wednesday.
In a cryptocurrency transaction, they sent a message to Poly Network saying that they were "ready to return" the funds. A response from DeFi requested that money be sent to 3 crypto addresses.
Approximately $4.8 million had been returned by midday London time.
About $2.1 million in crypto has been sent to two of these addresses by the attacker.
On the Polygon blockchain, they sent a total of 1,010,100 USDC stablecoins.
They followed up about an hour later with a transaction of 23.88 BTCB (a token pegged to the price of Bitcoin that works on the Binance Smart Chain network), worth approximately $1.103 million at current exchange rates.
Additionally, the hacker has sent $2.65 million to the Ethereum wallet provided by Poly Network (259 billion Shiba Inu tokens combined with 616,000 Fei USD stablecoins).