Incorrect validation of minBorrow amount

[c4-bot-5]

Lines of code

https://github.com/code-423n4/2023-12-ethereumcreditguild/blob/2376d9af792584e3d15ec9c32578daa33bb56b43/src/loan/LendingTerm.sol#L527-L531

Vulnerability details

Impact

Users who want to pay back their debt to leave exactly the minimum borrow amount will be unable to do so. This is because the check that ensures that the remaining borrowed amount of the user is up to the minimum borrowed amount is done incorrectly.

Proof of Concept

The check is too strict and will require the user to have more than the required minBorrow amount left as borrowed amount.

        require(
            borrowAmount - issuanceDecrease >
                ProfitManager(refs.profitManager).minBorrow(),
            "LendingTerm: below min borrow"
        );

In the check above, if minBorrow is 50, borrowAmount = 100, issuanceDecrease = 50,
at least 50, should be left as borrowed amount after payment, but this check fails because
100 - 50 = 50(minBorrow) > 50 //fails and revert

Tools Used

Manual review

Recommended Mitigation Steps

        require(
            borrowAmount - issuanceDecrease >=
                ProfitManager(refs.profitManager).minBorrow(),
            "LendingTerm: below min borrow"
        );

Assessed type

Invalid Validation

[c4-pre-sort]

0xSorryNotSorry marked the issue as sufficient quality report

[c4-pre-sort]

0xSorryNotSorry marked the issue as duplicate of #1182

[c4-judge]

Trumpero changed the severity to QA (Quality Assurance)

[c4-judge]

Trumpero marked the issue as grade-b

[c4-judge]

Trumpero marked the issue as grade-c