First Flight #6: Voting Booth

Summary

The logic put in place to handle remainder dust is ineffective.

Vulnerability Details

The function calculates the rewardPerVoter by dividing the totalRewards by totalVotes. In Solidity, division of integers always rounds down, which means that if totalRewards is not perfectly divisible by totalVotes, there will be some amount of "dust" (a small remainder of Ether) left over.

Impact

The function attempts to handle this by rounding up for the last voter, but this only accounts for up to 1 wei of dust. If the rounding down in the earlier payouts accumulates to more than 1 wei, the remaining dust will not be distributed.

Tools Used

Recommendations

This could potentially be improved by using a more precise method of division that can handle dust more accurately.