Dria
Swan
NFTHardhat
21,000 USDC
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Submission Details
Severity: low
Invalid

uncheked erc20 can lead to fund draining/freezing

cody

Summary

Vulnerability Details

https://github.com/Cyfrin/2024-10-swan-dria/blob/c3f6f027ed51dd31f60b224506de2bc847243eb7/contracts/swan/Swan.sol#L265-L271

Some tokens do not revert on failure, but instead return false. tranfser/transferfrom is directly used to send tokens in many places in the contract and the return value is not checked.
If the token transfer fails, it will cause a lot of serious problems.

// first, Swan receives the entire fee from seller
// this allows only one approval from the seller's side
token.transferFrom(asset.seller, address(this), buyerFee);
​
// send the buyer's portion to them
token.transfer(asset.buyer, buyerFee - driaFee);
​
// then it sends the remaining to Swan owner
token.transfer(owner(), driaFee);
}
​

Impact

If the token used in the pool is not reverting on failures, it can be exploited to drain liquidity in the pool as well as blindly freeze assets of lender forever in the contract.

Tools Used

vscode

Recommendations

Using OpenZeppelin’s SafeERC20 versions with the safeTransfer and safeTransferFrom functions that handle the return value check as well as non-standard-compliant tokens.

Updates

Lead Judging Commences

inallhonesty Lead Judge 8 months ago
Submission Judgement Published
Invalidated
Reason: Known issue
Assigned finding tags:

[KNOWN] - Low-35 Unsafe use of transfer()/transferFrom() with IERC20

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