Submission Details
Severity:
Reentrancy Vulnerability in `KittyVault::executeWhiskdrawal`
Description: The KittyVault::executeWhiskdrawal function calls an external contract to transfer tokens before updating the state, which could lead to a reentrancy attack.
Impact: An attacker could drain funds or cause other unexpected behavior by reentering the contract.
Proof of Concept: An attacker could create a malicious contract that reenters the KittyVault contract:
contract Malicious {
KittyVault public vault;
constructor(address _vault) {
vault = KittyVault(_vault);
}
function attack() public {
vault.executeWhiskdrawal(address(this), 1);
}
function receive() external payable {
vault.executeWhiskdrawal(address(this), 1);
}
}
Recommended Mitigation: Use the Checks-Effects-Interactions pattern to update the state before calling external contracts.
function executeWhiskdrawal(address _user, uint256 _cattyNipToWithdraw) external onlyKittyPool {
collateral[_user] -= _cattyNipToWithdraw;
IERC20(token).transfer(_user, _cattyNipToWithdraw);
}
Rewards breakdown
nSLOC
224This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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