$320 million stolen from Wormhole, bridge linking solana and ethereum

One of the most popular bridges linking the ethereum and solana blockchains lost more than $320 million Wednesday afternoon in an apparent hack.

It is DeFi’s second-biggest exploit ever, just after the $600 million Poly Network crypto heist, and it is the largest attack to date on solana, a rival to ethereum that is increasingly gaining traction in the non-fungible token (NFT) and decentralized finance (DeFi) ecosystems.

Ethereum is the most used blockchain network, and it is a big player in the world of DeFi, in which programmable pieces of code known as smart contracts can replace middlemen like banks and lawyers in certain types of business transactions. A more recently introduced competitor, solana, is growing in popularity, because it is cheaper and faster to use than ethereum.

Crypto holders often do not operate exclusively within one blockchain ecosystem, so developers have built cross-chain bridges to let users send cryptocurrency from one chain to another.

Wormhole is a protocol that lets users move their tokens and NFTs between solana and ethereum.

Developers representing Wormhole confirmed the exploit on its Twitter account, saying that the network is “down for maintenance” while it looks into a “potential exploit.” The protocol’s official website is currently offline.

An analysis from blockchain cybersecurity firm CertiK shows that the attacker’s profits thus far are at least $251 million worth of ethereum, nearly $47 million in solana, and more than $4 million in USDC, a stablecoin pegged to the price of the U.S. dollar.

Bridges like Wormhole work by having two smart contracts — one on each chain, according to Auston Bunsen, co-founder of QuikNode, which provides blockchain infrastructure to developers and companies. In this case, there was one smart contract on solana and one on ethereum. A bridge like Wormhole takes an ethereum token, locks it into a contract on…