Submission Details
Severity:
The contract can be drained by reentering refund function
Summary
A user can drain the contract using a malicious contract that reenter refund function.
Vulnerability Details
A malicious contract can re-enter refund function here:
payable(msg.sender).sendValue(entranceFee);
CEI pattern is not followed because players[playerIndex] = address(0) is executed after the external call.
Impact
All ETH in the contract can be drained.
Tools Used
Manual review
Recommendations
Follow CEI pattern:
function refund(uint256 playerIndex) public {
address playerAddress = players[playerIndex];
require(playerAddress == msg.sender, "PuppyRaffle: Only the player can refund");
require(playerAddress != address(0), "PuppyRaffle: Player already refunded, or is not active");
players[playerIndex] = address(0);
payable(msg.sender).sendValue(entranceFee);
emit RaffleRefunded(playerAddress);
}
In addition use nonReentrant() modifier by OpenZeppelin ReentrancyGuard contract.
Updates
Lead Judging Commences
Hamiltonite about 2 years ago
Submission Judgement Published Assigned finding tags:
reentrancy-in-refund
reentrancy in refund() function
Rewards breakdown
nSLOC
143This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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