Last Man Standing
First Flight #45
Beginner FriendlyFoundrySolidity
100 EXP
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Submission Details
Impact: medium
Likelihood: high
Invalid

Untracked ETH Sent to receive() Function

r4y4n3

Root + Impact

Description

  • All ETH sent to the contract should either be part of the game mechanics (pot/fees) or be rejected.

    Specific issue:
    The contract has a receive() function that accepts ETH but doesn't update any state variables. This ETH becomes orphaned - it exists in the contract balance but is not tracked in pot, platform fees, or winnings.

receive() external payable {
// @> Accepts ETH but doesn't update any state variables
// This ETH becomes orphaned and untrackable
}

Risk

Likelihood:

  • Users accidentally send ETH directly to contract address.

  • UI bugs cause incorrect transaction formatting.

  • Users confuse direct transfers with game participation.

Impact:

  • ETH becomes permanently orphaned and unrecoverable.

  • Contract balance exceeds tracked amounts (pot + platform fees + winnings).

  • Value is lost with no way to recover through game mechanics.

Proof of Concept

function testUntrackedETHSentToReceive() public {
uint256 potBefore = game.pot();
uint256 platformFeesBefore = game.platformFeesBalance();
uint256 contractBalanceBefore = game.getContractBalance();
​
// Send ETH directly to contract
uint256 orphanedETH = 1 ether;
vm.startPrank(player1);
(bool success,) = address(game).call{value: orphanedETH}("");
assertTrue(success, "Direct ETH transfer should succeed");
vm.stopPrank();
​
// ETH was accepted but not tracked anywhere
assertEq(game.pot(), potBefore, "Pot should not increase");
assertEq(game.platformFeesBalance(), platformFeesBefore, "Platform fees should not increase");
assertEq(game.getContractBalance(), contractBalanceBefore + orphanedETH, "Contract balance increased");
​
// ETH is now orphaned
uint256 untrackedETH = game.getContractBalance() - game.pot() - game.platformFeesBalance();
assertEq(untrackedETH, orphanedETH, "ETH should be untracked/orphaned");
}

Recommended Mitigation

Reject direct transfers

receive() external payable {
- // Empty function that accepts ETH
+ revert("Game: Use claimThrone() to participate");
}
Updates

Appeal created

inallhonesty Lead Judge 9 days ago
Submission Judgement Published
Invalidated
Reason: Non-acceptable severity
Assigned finding tags:

Direct ETH transfers - User mistake

There is no reason for a user to directly send ETH or anything to this contract. Basic user mistake, info, invalid according to CH Docs.

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