Monad DeFi Project Echo Protocol Hacked for More Than $800,000 After Admin Key Leak

Echo Protocol is a Bitcoin liquidity and yield-focused DeFi protocol deployed on Monad, with eBTC serving as its on-chain Bitcoin asset. SlowMist founder Cosine said the incident was not caused by a smart-contract code vulnerability but by a single point of failure: minting authority was concentrated in one Admin private key. Once that key was compromised, the entire asset-backing mechanism and lending market were at risk of failure.

On May 18, 2026, the attacker stole the Admin private key and minted 1,000 unbacked eBTC on Monad with a nominal value of about $76.7 million. The attacker used 45 eBTC to borrow 11.3 WBTC from Curvance, bridged the funds and deposited them into Tornado Cash, resulting in an actual loss of about $816,000. Echo Protocol later regained control and burned the remaining 955 eBTC held by the attacker.