Alchemix Transmuter

Vulnerability Details

The claimAndSwap functions in the Strategies contracts enforces the strict condition on the swap from WETH to ALETH. The keeper specifies the _amountClaim and the _minOut for slippage, However the require statement

require(_minOut > _amountClaim, "minOut too low");

only allows the _minOut to be greater than the _amountClaim which is the amount of WETH to claim from the transmuter.

In situations where there is a 1:1 condition the transaction would revert as a result of the require statment

require((balAfter - balBefore) >= _minOut, "Slippage too high");

StrategryArb

https://github.com/Cyfrin/2024-12-alchemix/blob/82798f4891e41959eef866bd1d4cb44fc1e26439/src/StrategyArb.sol#L71C1-L78C6

https://github.com/Cyfrin/2024-12-alchemix/blob/82798f4891e41959eef866bd1d4cb44fc1e26439/src/StrategyArb.sol#L81C1-L88C6

StrategyMainet

https://github.com/Cyfrin/2024-12-alchemix/blob/82798f4891e41959eef866bd1d4cb44fc1e26439/src/StrategyMainnet.sol#L99

StrategyOp

https://github.com/Cyfrin/2024-12-alchemix/blob/82798f4891e41959eef866bd1d4cb44fc1e26439/src/StrategyOp.sol#L79C3-L89C6

https://github.com/Cyfrin/2024-12-alchemix/blob/82798f4891e41959eef866bd1d4cb44fc1e26439/src/StrategyOp.sol#L95C3-L103C6

Impact

1. Transaction will revert if there is a 1:1 condition

Tools Used

Manual review

Recommendations

1. update the operator >= to allow transactions of equal amount.

   require(_minOut >= _amountClaim, "minOut too low");