Submission Details
Severity:
Fees are rounded down in favour of user
Summary
In `MembershipFactory::joinDAO` the platformFees are being rounded down in favour of the user.
Vulnerability Details
Looking at the code below we can observe that platformFees is being rounded down and after is subtracted from the tierPrice which is paid by the user. So in cases where there are round downs, the msg_sender() gets a few more wei from the round down resulting in him being favoured.
function joinDAO(address daoMembershipAddress, uint256 tierIndex) external {
...
uint256 tierPrice = daos[daoMembershipAddress].tiers[tierIndex].price;
uint256 platformFees = (20 * tierPrice) / 100; //@audit rounding down of fees
daos[daoMembershipAddress].tiers[tierIndex].minted += 1;
IERC20(daos[daoMembershipAddress].currency).transferFrom(_msgSender(), owpWallet, platformFees);
IERC20(daos[daoMembershipAddress].currency).transferFrom(_msgSender(), daoMembershipAddress, tierPrice - platformFees);
...
}
Impact
Rounding down of fees.
Tools Used
manual review
Recommendations
Platform fees should be rounded against user
Prize pool breakdown
Total prize
15,000 USDC
nSLOC
54128 USDC / LOC
14,000 USDC
1,000 USDC
Live
The contest is live. Earn rewards by submitting a finding.
Appeals
This is your time to appeal against judgements on your submissions.
Appeals Review
Appeals are being carefully reviewed by our judges.