Submission Details
Severity:
if the collateral token is a erc777 lender.sol can be drained
Summary
Due to the lack of reentrancy guard in the code, if the token is an ERC777, the lender can be drained
Vulnerability Details
function seizeLoan(uint256[] calldata loanIds) public {
for (uint256 i = 0; i < loanIds.length; i++) {
uint256 loanId = loanIds[i];
// get the loan info
Loan memory loan = loans[loanId];
// validate the loan
if (loan.auctionStartTimestamp == type(uint256).max)
revert AuctionNotStarted();
if (
block.timestamp <
loan.auctionStartTimestamp + loan.auctionLength
) revert AuctionNotEnded();
// calculate the fee
uint256 govFee = (borrowerFee * loan.collateral) / 10000;
// transfer the protocol fee to governance
IERC20(loan.collateralToken).transfer(feeReceiver, govFee);
// transfer the collateral tokens from the contract to the lender
IERC20(loan.collateralToken).transfer(
loan.lender,
loan.collateral - govFee
);
bytes32 poolId = keccak256(
abi.encode(loan.lender, loan.loanToken, loan.collateralToken)
);
// update the pool outstanding loans
pools[poolId].outstandingLoans -= loan.debt;
emit LoanSiezed(
loan.borrower,
loan.lender,
loanId,
loan.collateral
);
// delete the loan
delete loans[loanId];
}
}
As you can see, due to the lack of reentrancy guard in the seizeLoan function, a malicious user can exploit this with a reentrancy attack and steal all funds
Impact
lender.sol can be drained
Tools Used
manual review
Recommendations
add reentrancyGuard
Prize pool breakdown
Total prize
20,000 USDC
nSLOC
70628
USDC / LOC
18,000 USDC
2,000 USDC
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