Upgraded Q -> M from #366 [1670366212013]

Judge has assessed an item in Issue 366 as M risk. The relevant finding follows: 1. Not support fee-on-transfer tokens Every tokens of credit line will be transferred from lender to LineOfCredit first, then to borrower later. These 2-transfer steps will make the tax for some fee-on-transfer token...

Payable functions do not refund excess and locks in

Lines of code Vulnerability details Impact All payable functions addCredit, increaseCredit, depositAndClose, depositAndRepay, closehttps://github.com/debtdao/Line-of-Credit/blob/698...

## Potential for loops hitting the block gas limit

Lines of code Vulnerability details Proof of Concept A malicious/compromised LineOfCredit arbiter can add a huge amount of collaterals to the Escrow by calling enableCollateral. This method pushes each collateral token to an array that is then iterated over in getCollateralValue. If the array siz...

Closing an unexisting credit can overflow the credit count variable in the LineOfCredit contract

Lines of code Vulnerability details The LineOfCredit contract doesn't verify if a credit exists and is properly initialized when closing it, and will update its state anyway, leading to an inconsistent count. Impact The close function in the LineOfCredit contract doesn't check if the given credit...

Borrower can craft a borrow that cannot be liquidated, even by arbiter.

Lines of code Vulnerability details Description LineOfCredit manages an array of open credit line identifiers called ids. Many interactions with the Line operate on ids0, which is presumed to be the oldest borrow which has non zero principal. For example, borrowers must first deposit and repay to...

Potential DoS when closing a credit nominated in ETH in the LineOfCredit contract

Lines of code Vulnerability details When closing a credit that was issued in ETH, the LineOfCredit contract will send the lender his deposit and any accrued interests using the address.transferamount function, which may fail and revert the whole function, leading to an eventual DoS. Impact The...

Line of credit status can be set to REPAID even if having credits with debt

Lines of code Vulnerability details A malicious borrower can close non-existing credits to alter the status of the credit to LineLib.STATUS.REPAID, even if having open credit with debt. Impact The close function in the LineOfCredit contract can be used to close non-existing credits, which will...

Unlimited length of LineOfCredit.ids: storage collisions

Lines of code Vulnerability details Impact There are no restrictions for ids length So malicious borrower may create many credits and replace storage slot data at some position Proof of Concept 1. LineOfCredit.ids saves array size in slot Oracle data feed is insufficiently validated in Oracle.sol...

Functions addCredit(...) and increaseCredit(...) can lock lender’s ETH forever

Lines of code Vulnerability details Impact In LineOfCredit contract, both functions addCredit... and increaseCredit... require mutual consent between lender and borrower. If lender is tricked by borrower, or by mistake, lender ETH will be locked in the contract forever. function addCredit uint128...

Arbitrary call order to handle mutual consent can lead to unrecoverable native ETH

Lines of code Vulnerability details Creating new credits and increasing the credit deposit requires both parties, the lender and the borrower, to agree. This is implemented by having both call the same function with the same call data. However, as it's possible to use native ETH as a credit token...

Borrower can close non-existent credit line positions to effectively force the overall status to REPAID

Lines of code Vulnerability details The LineOfCredit.close function is used to close a credit line position. Both the lender of a specific credit position and the borrower can call this function. However, the function does not check if the given id belongs to a credit line position in the credits...

Borrower can manipulate the repayment queue, avoid paying back the initial lender

Lines of code Vulnerability details Impact In contract LineOfCredit, the repayment queue protects lenders and assured that they have to get paid back. Without a queue, a borrower could constantly refinance to lower rates and avoid paying back the initial lender from sponsors. Every time, borrower...