Lien Finance hit by $542K exploit tied to bond token logic bug

Lien Finance has lost about $542,000 in USDC after an attacker exploited a flaw in its bond token logic to mint unsupported assets and drain liquidity from the protocol. Summary Lien Finance lost about $542,000 in USDC after attackers exploited a flaw in its bond token exchange logic. Security researchers said the exploit allowed unsupported bond tokens to be minted and exchanged for real liquidity from the protocol. The incident adds to a series of DeFi exploits this month as researchers continue to examine weaknesses in protocol pricing and validation logic. Blockchain security firm SlowMist said the exploit targeted Lien Finance’s bond exchange mechanism, allowing the attacker to create bond tokens without destroying the corresponding input bonds before swapping them for USDC. The firm estimated the loss at roughly 542,144.63 USDC and identified the attacker wallet as 0x0d7d…1808a. 🚨SlowMist TI Alert🚨💸 @LienFinance Loss: ~542k USD🔍 Root Cause: The `exchangeEquivalentBonds` function in BondMakerCollateralizedEth lacks proper multiset integrity checks. It only counts total exception occurrences instead of verifying each bondID's appearance per group.…— SlowMist (@SlowMist_Team) Ju...