First Flight #2: Puppy Raffle

Summary

withdrawFees() is used to transfer the accumulated fees to the feeAddress. However, a notable issue is that the function always reverts if anyone sends ether directly to the contract

Vulnerability Details

withdrawFees() has a require(address(this).balance == uint256(totalFees) to verify the presence of active players. The issue arises when someone sends only 1 wei to the contract, preventing the require condition from being met. This situation can lead to DOS attack, effectively blocking the funds within the contract. The vulnerability arises from the use of address(this).balance in the comparison, and an attacker can exploit this by creating a malicious contract with a selfdestruct() pointing to the contract, ensuring that the require condition is never satisfied.

Impact

DOS provocating a lock of funds.

Tools Used

Manual review

Recommendations

Instead of using address(this).balance use a virtual balance to store the balance of the contract.