Submission Details
Severity:
Reentrancy in Claim() at Staking.sol
Vulnerability Details
It was found that claim() function of Staking.sol doesn't implement checks-effects-interactions pattern therefore leaving the function vulnerable to reentrancy attacks.
function claim() external {
updateFor(msg.sender);
WETH.transfer(msg.sender, claimable[msg.sender]);
claimable[msg.sender] = 0;
balance = WETH.balanceOf(address(this));
}
the function transfers the claimable balance to the msg.sender first and then in the next line updates the state with claimable[msg.sender] = 0;
Impact
An attacker could exploit the contract to re-enter the claim() function several times leading to drain it from funds.
Tools Used
Manual Review.
Recommendations
It is advisable to use checks-effects-interactions pattern and to use nonReentrant() modifier as an added layer of security.
Prize pool breakdown
Total prize
20,000 USDC
nSLOC
70628 USDC / LOC
18,000 USDC
2,000 USDC
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