First Flight #17: Dussehra
First Flight #17
Beginner FriendlyFoundryNFT
100 EXP
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Submission Details
Severity: low
Invalid

Reentrancy in `Dussehra.sol`

carlosalbawork

Summary

Reentrancy in the function Dussehra::withdraw

Vulnerability Details

The function

​
function withdraw() public RamIsSelected OnlyRam RavanKilled {
if (totalAmountGivenToRam == 0) {
revert Dussehra__AlreadyClaimedAmount();
}
uint256 amount = totalAmountGivenToRam;
(bool success, ) = msg.sender.call{value: amount}("");
require(success, "Failed to send money to Ram");
totalAmountGivenToRam = 0;
}
​

Contains a reentrancy issue. totalAmountGivenToRam is updated after the call function. Therefore, an atacker could reenter the function and get all the funds of the contract before updating totalAmountGivenToRam to 0.

Impact

All the funds of the contract could be drained

Tools Used

Manual review

Recommendations

Change the order of the calls:

​
function withdraw() public RamIsSelected OnlyRam RavanKilled {
if (totalAmountGivenToRam == 0) {
revert Dussehra__AlreadyClaimedAmount();
}
uint256 amount = totalAmountGivenToRam;
+ totalAmountGivenToRam = 0;
(bool success, ) = msg.sender.call{value: amount}("");
require(success, "Failed to send money to Ram");
- totalAmountGivenToRam = 0;
}
​
Updates

Lead Judging Commences

bube Lead Judge about 1 year ago
Submission Judgement Published
Invalidated
Reason: Non-acceptable severity
Assigned finding tags:

Invalid - reentrancy in withdraw

The `withdraw` function sends the given amount to Ram. If the attacker calls the `withdraw` function again before the state variable is changed, the function will revert because there are no more funds in the contract. This reentrancy has no impact for the protocol. It is recommended to follow the CEI pattern, but this is informational.

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