protocolFeeRecipient might take unclaimed reward token after quest ends.

[code423n4]

Lines of code

https://github.com/rabbitholegg/quest-protocol/blob/8c4c1f71221570b14a0479c216583342bd652d8d/contracts/Erc20Quest.sol#L102-L104

Vulnerability details

Impact

Since there is no code to check whether fee has been drawn, withdrawFee() might be called multiple times.
This allows protocolFeeRecipient to steal all of the unclaimed reward tokens after quest ended.

Proof of Concept

Provide direct links to all referenced code in GitHub. Add screenshots, logs, or any other relevant proof that illustrates the concept.

Tools Used

Sublime Text

Recommended Mitigation Steps

Add a code to confirm that the fee can be withdrawn only once as shown below.

bool public withdrawal = false;

function withdrawFee() public onlyAdminWithdrawAfterEnd {
		require(withdrawal == false, "already took withdraw fee");
		withdrawal = true;
		IERC20(rewardToken).safeTransfer(protocolFeeRecipient, protocolFee()); 
}

[c4-judge]

kirk-baird marked the issue as duplicate of #23

[c4-judge]

kirk-baird marked the issue as satisfactory