Exploit Robs Nearly $200M From Cross-Chain Messaging Protocol Nomad
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Similar to other cross-chain bridges, Nomad enables users to transfer tokens back and forth between several blockchains. The attack on Monday is the most recent in a line of widely reported instances that have raised concerns about the safety of cross-chain bridges. Through Twitter, the Nomad team acknowledged the hack.
What Happened With Nomad
Bridges typically function by reissuing tokens in "wrapped" form on a different chain after locking them up in a smart contract on one network. The wrapped tokens lose their backing if the smart contract where they initially deposited them is compromised, as in Nomad's instance, making them worthless. The Nomad attack was a free-for-all, unlike some bridge attacks where a single perpetrator is responsible for the entire vulnerability.
Bridge attacks have increased in frequency recently as cryptocurrency users have shown a greater desire to transfer funds between blockchains. While cross-chain bridges have enabled the spread of fledgling blockchains, bridge failures can be disastrous for smaller chains that depend on them for a significant portion of their overall liquidity.
The Ronin bridge attack in April, the most prominent decentralized finance (DeFi) attack in history, resulted in the theft of over $600 million in cryptocurrency from the bridge that drives the blockchain-based game Axie Infinity.