First Flight #9: Soulmate
First Flight #9
Beginner FriendlyFoundryNFT
100 EXP
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Submission Details
Severity: high
Valid

Any arbitrary address can claim love tokens everyday, without even matching up with a soulmate.

dimah7

Summary

Airdrop::claim function allows any malicious user to claim LoveToken everyday, since there is no requirement for the callers of the function to have a soulmate.

Vulnerability Details

Add the following to the AirdropTest.t.sol file:

function testAnyoneCanClaim() public {
address user = makeAddr("user");
​
vm.warp(block.timestamp + 1 days);
​
vm.startPrank(user);
airdropContract.claim();
​
vm.warp(block.timestamp + 1 days);
airdropContract.claim();
​
vm.warp(block.timestamp + 1 days);
airdropContract.claim();
vm.stopPrank();
​
assert(loveToken.balanceOf(user) == 3e18);
}

Impact

High: Any address can directly steal tokens from aidrop vault's funds.

Tools Used

Manual Review, Foundry

Recommendations

Add a check in Airdrop::claim function, that checks if the caller of the function has a soulmate:

function claim() public {
+ if (soulmateContract.soulmateOf(msg.sender) == address(0)) revert();
​
// No LoveToken for people who don't love their soulmates anymore.
if (soulmateContract.isDivorced()) revert Airdrop__CoupleIsDivorced();
​
// Calculating since how long soulmates are reunited
uint256 numberOfDaysInCouple = (block.timestamp -
soulmateContract.idToCreationTimestamp(
soulmateContract.ownerToId(msg.sender)
)) / daysInSecond;
​
uint256 amountAlreadyClaimed = _claimedBy[msg.sender];
​
if (
amountAlreadyClaimed >=
numberOfDaysInCouple * 10 ** loveToken.decimals()
) revert Airdrop__PreviousTokenAlreadyClaimed();
​
uint256 tokenAmountToDistribute = (numberOfDaysInCouple *
10 ** loveToken.decimals()) - amountAlreadyClaimed;
​
// Dust collector
if (
tokenAmountToDistribute >=
loveToken.balanceOf(address(airdropVault))
) {
tokenAmountToDistribute = loveToken.balanceOf(
address(airdropVault)
);
}
_claimedBy[msg.sender] += tokenAmountToDistribute;
​
emit TokenClaimed(msg.sender, tokenAmountToDistribute);
​
loveToken.transferFrom(
address(airdropVault),
msg.sender,
tokenAmountToDistribute
);
}
Updates

Lead Judging Commences

0xnevi Lead Judge over 1 year ago
Submission Judgement Published
Validated
Assigned finding tags:

finding-claim-airdrop-without-owning-NFT

High severity, This issue is separated from the flawed `isDivorced()` check presented in issue #168 as even if that is fixed, if ownership is not checked, isDivorced would still default to false and allow bypass to claim airdrops by posing as tokenId 0 in turn resulting in this [important check for token claim is bypassed.](https://github.com/Cyfrin/2024-02-soulmate/blob/b3f9227942ffd5c443ce6bccaa980fea0304c38f/src/Airdrop.sol#L61-L66). #220 is the most comprehensive issue as it correctly recognizes both issues existing within the same function.

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