Beedle - Oracle free perpetual lending

Impact

Loss of Funds through MEV

Proof of Concept

Fees contract uses exactInputSingle call whose role is to swap the tokens through Uniswap router.

Link to code

Issue here is that the amountOutMin value has been set to 0 in both the cases. As there is no slippage protection, a malicious actor could, e.g., trivially insert transactions before and after this swapping transaction (using the infamous "sandwich" attack), causing the smart contract to trade at a radically worse price, profit from this at the caller's expense, and then return the contracts to their original state, all at a low cost.

Tools Used

VS Code

Recommended Mitigation Steps

Recommend to add a amountOutMin parameter in the function.