Harmony's Horizon Bridge Hacker Begins Laundering Stolen $100 Million Using Mixer

The hackers behind the $100 million (roughly Rs. 784 crore) altcoin theft from Harmony Protocol's Horizon Bridge have started laundering the funds as per blockchain security company PeckShield. Etherscan data reveals that the wallet used by the cyber thieves in the attack sent out 18,000 ETH to a total of four wallet addresses. The development comes after Harmony offered a $1 million (roughly 7.8 crore) bounty for the return of the stolen funds while also offering to waive law enforcement action should the hacker return the stolen crypto assets.

As on-chain data shows, the hackers first sent out around 18,000 ETH, worth around $21 million (roughly Rs. 165 crore), to another wallet. Afterward, the cybercriminals used the receiving wallet to disburse 6,000 ETH, worth around $7 million (roughly Rs. 55 crore) each, to three other addresses.

The hacker has already laundered funds sent to the first intermediary address through Tornado Cash. Funds from the second and third receiving addresses have also been laundered in batches of 100 ETH, or $116,000 (roughly Rs. 91 lakh).

The hacker sole $100 million (roughly Rs. 784 crore) in several crypto coins and swapped them for Ethereum. Coins stolen were Wrapped Ethereum, Tether (USDT), and USD Coin (USDC) stablecoins.

Harmony's blockchain bridge enables users to transfer digital assets between different blockchains, the most notable of which are the Binance Smart Chain, Ethereum, Bitcoin, and Harmony networks. The hacker used this to their advantage, stealing a variety of digital assets spanning NFTs, metaverse land, and wrapped Ether.

Hackers recently have been targeting cross-chain bridges. Qubit Finance's bridge was hacked for $80 million (roughly Rs. 628 crore) back in January, thieves stole $320 million (roughly Rs. 2,510 crore) from the Wormhole bridge a month later, and hackers drained $625 million (roughly Rs. 4,730 crore) in Ether and USDC from Axie Infinity's Ronin bridge in March.