Beedle - Oracle free perpetual lending

Summary

amountOutMinimum is used to specify the minimum amount of tokens the caller wants to be returned from a swap. Using amountOutMinimum = 0 tells the swap that the caller will accept a minimum amount of 0 output tokens from the swap, opening up the user to a catastrophic loss of funds via MEV bot sandwich attacks.

Vulnerability Details

ISwapRouter.ExactInputSingleParams memory params = ISwapRouter
.ExactInputSingleParams({
tokenIn: _profits,
tokenOut: WETH,
fee: 3000,
recipient: address(this),
deadline: block.timestamp,
amountIn: amount,
amountOutMinimum: 0,
sqrtPriceLimitX96: 0
});

Using amountOutMinimum = 0 tells the swap that the caller will accept a minimum amount of 0 output tokens from the swap

Impact

loss of funds via MEV bot sandwich attacks.

Tools Used

Manual

Recommendations

Use parameters amountOutMinimum correctly to avoid loss of funds.