Ankr bridge exploit drains $303K after Optimism deposit reused

Ankr's Ethereum cross-chain bridge has suffered an exploit involving five unauthorized withdrawals that drained more than $303,000 in crypto assets on Nov. 9, raising questions about the bridge's transaction verification process. Ankr's Ethereum bridge lost over $303,000 after an attacker executed five unauthorized withdrawals on Monday. The attacker reportedly reused an Optimism deposit to withdraw five different tokens from Ethereum's bridge. Blockaid flagged the exploit as ongoing, with the bridge's public pause flag initially remaining false. Ankr had not responded to questions about affected services, bridge security, or possible user reimbursements. Blockchain security firm Blockaid identified the attack on Monday, reporting that an attacker used a small deposit on Optimism to withdraw assets locked in Ankr's Ethereum bridge.