SensoYard - Unprotected slippage tolerance can lead to user/protocol loss of funds

[sherlock-admin]

SensoYard

medium

Unprotected slippage tolerance can lead to user/protocol loss of funds

Summary

The USSDRebalancer contract executes swaps without slippage protection. This may cause a loss of funds because of sandwich attacks (especially during times of high volatility when large swaps can be executed).

Vulnerability Detail

Swaps in the BuyUSSDSellCollateral and SellUSSDBuyCollateral functions will be sandwiched causing a loss of funds for users and the protocol.

Impact

Loss of funds due to sandwich attacks.

Code Snippet

https://github.com/sherlock-audit/2023-05-USSD/blob/main/ussd-contracts/contracts/USSD.sol#L227-L240

    function UniV3SwapInput(
        bytes memory _path,
        uint256 _sellAmount
    ) public override onlyBalancer {
        IV3SwapRouter.ExactInputParams memory params = IV3SwapRouter
            .ExactInputParams({
                path: _path,
                recipient: address(this),
                //deadline: block.timestamp,
                amountIn: _sellAmount,
                amountOutMinimum: 0
            });
        uniRouter.exactInput(params);
    }

Tool used

Manual Review

Recommendation

Slippage parameters should be passed to the UniV3SwapInput function. You may use an oracle to get an estimate of the price.

Duplicate of #673