Submission Details
Severity:
Malicious user can exploit the contract by reenter the refund
Summary
Malicious user can exploit the contract by reenter the refund
Vulnerability Details
refund will send entranceFee to msg.sender and players[playerIndex] is not updated. Attacker can reenter the refund and drain the contract.
/// @param playerIndex the index of the player to refund. You can find it externally by calling `getActivePlayerIndex`
/// @dev This function will allow there to be blank spots in the array
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");
payable(msg.sender).sendValue(entranceFee);
players[playerIndex] = address(0);
emit RaffleRefunded(playerAddress);
}
Impact
The attacker can drain the contract of its funds.
Tools Used
Manual review.
Recommendations
Add reentrancy protection.
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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