Uniswap v4 Hooks 54.2% Classified as Malicious... Routing Responsibility Dispute

Decentralized exchange (DEX) aggregator 0x has analyzed 84,163 Uniswap v4 hooks across six blockchains as of September 11, with 54.2% classified as malicious. The analysis suggests malicious hooks could apply different conditions during quote and execution phases, sparking a dispute over routing responsibility.

0x announced on September 14 that it conducted static and dynamic analysis along with observing actual executed trades to assess the hooks. Only 19.4% of hooks were classified as safe, while 26.4% showed potential malicious activity. The firm explained that malicious hooks could present attractive prices to aggregators and wallets to initiate trades before altering fees or exchange conditions during execution, potentially causing users to receive up to 50% less assets than quoted.

Real-world examples were provided: A hook on Base processed 6,516 ETH-NVDAc trades, imposing fees on 3,946 transactions with a median fee of 18%. Another hook connected to BNB's USDT-WBNB pair charged fees in 1,619 out of 4,879 trades, with a median fee of 12.8%.

0x reported routing 81.92 million transactions totaling $4.267 billion (approximately 5.747 trillion won) this year, with about 70% accessing Uniswap liquidity. The firm stated it has strengthened detection technology and liquidity pool review processes to prevent suspicious pools from affecting routing outcomes.

Uniswap v4 hooks are smart contract plugins that modify how pools, swaps, fees, and liquidity positions operate. Developers can add separate logic before and after swaps for dynamic fees, on-chain limit orders, and liquidity management. Hooks can be developed by third parties independent of Uniswap Labs, increasing functionality but requiring users to verify the logic in their routing paths.

Uniswap operates a review process to include hooks in its routing allowlist, though it clarified this is not a security audit or guarantee of safety. Hayden Adams, Uniswap founder, urged users to avoid bad hooks, stating that using Uniswap's API and routing features can help avoid problematic hooks.

Dan Robinson of Paradigm argued 0x's analysis should be titled '0x Routing Mistake,' noting aggregators shouldn't route through arbitrary hooks and Uniswap routers have approval processes. The dispute highlights the tension between hook openness and verification responsibility during trade execution.