defi-amm-security

Prevent reentrancy by following checks-effects-interactions ordering and applying OpenZeppelin's ReentrancyGuard nonReentrant modifier to external entrypoints. Update internal balances before transferring tokens, and use SafeERC20 for transfers instead of writing a custom guard.

A donation attack manipulates share math by sending tokens directly to the contract, inflating token.balanceOf(address(this)) used as the denominator. Mitigate it by tracking internal accounting state and measuring actual tokens received during deposits rather than reading raw balances.

Protect against oracle manipulation by using a TWAP from Uniswap V3's observe function instead of spot prices, which are flash-loan manipulable. Query tick cumulatives over a window such as 30 minutes and derive the price from the time-weighted average tick.

Yes, the checklist requires every swap path to accept caller-provided amountOutMin and deadline parameters. The swap must revert if the deadline has passed or if the calculated output falls below the minimum, protecting users from sandwich attacks and stale quotes.

Use Slither for static analysis, Echidna for property-based testing, and Foundry's forge test with high fuzz runs for invariant checking. Run these only in a trusted checkout or sandbox, and never include private keys or RPC credentials in commands or reports.

Use Uniswap V3's FullMath.mulDiv for reserve math where naive a * b / c can overflow before the division. This applies to large reserve or share calculations in AMM contracts where intermediate products may exceed uint256 bounds.