Open howlbot-integration[bot] opened 2 months ago
However, the market could become delinquent after the APR is reduced because some lenders might want to exit. If this occurs alongside situation (2), the borrower would be unable to lock the APR at 7% or set the APR to 5.25% two weeks later, or increase the APR.
A few points here:
With respect to restoring the APR back to the original, it'd be ideal if that was allowed, but the restriction is at the market level as a general rule that markets can not be made delinquent by changes to their config.
Overall I'd consider this a low/informational, certainly not a high especially given this only has the effect of incurring penalties for delinquent borrowers (if the reserve ratio is X, they are obligated to keep sufficient assets in the market for X% of the supply at all times).
I consider this a valid L - it is reasonable that the delinquent borrower is required to bring the loan back to a healthy state before applying settings
3docSec changed the severity to QA (Quality Assurance)
3docSec marked the issue as grade-b
First, I respectfully disagree that the delinquent borrower is required to bring the loan back to a healthy state before applying settings, because the borrower can apply settings under delinquent status anyway as long as they initially reduces APR no more than 25%.
Second, it is reasonable that a borrower should be allowed to increase APR without any restriction, this could help the market to attract more assets and bring the market to be healthy. The current implementation works as below:
As we can see, the above situations are handled inconsistently.
I agree that the borrower should not be allowed to decrease reserve ratio by increasing the APR. However, the protocol should not prevent the borrower from increasing the APR to attract more collateral, even if the market is in a delinquent status.
There's no need to press on the point of how the protocol "should" behave: I am sold on that one, and that's why this issue was not closed as invalid / intended behavior. Because of the reasons discussed in previous comments, however, I don't see fit for H/M severity, because while the intent of the protocol is likely as you understood it, it makes little sense for a borrower to increase the rate of a loan they fell already behind with
Lines of code
https://github.com/code-423n4/2024-08-wildcat/blob/main/src/market/WildcatMarketConfig.sol#L146-L150
Vulnerability details
Impact
if the market becomes delinquent following a reduction of over 25% in APR:
Proof of Concept
The Wildcat protocol specifies that a borrower can reduce the APR of their market as follows:
Suppose the initial APR of a market is 10%, and its
reserveRatioBips
is 20%:setAnnualInterestAndReserveRatioBips()
on the market with the current APR(7.5%)setAnnualInterestAndReserveRatioBips()
on the market with the current APR(7%)However, the market could become delinquent after the APR is reduced because some lenders might want to exit. If this occurs alongside situation (2), the borrower would be unable to lock the APR at 7% or set the APR to 5.25% two weeks later, or increase the APR.
Copy below codes to WildcatMarket.t.sol and run
forge test --match-test test_setAnnualInterestAndReserveRatioBips_RestoreOrLockCallRevert
:Tools Used
Manual review
Recommended Mitigation Steps
If the APR was reduced over 25% initially, since the borrower has repaid enough asset in this APR reduction to allow lenders opting out:
However, it seems impossible to fix this issue in the current logic by slight improvement.
Since Reducing APR logic works for all market and it is not tied to any specific hook, It is recommended to move all codes in MarketConstraintHooks#onSetAnnualInterestAndReserveRatioBips() to WildcatMarketConfig.sol, and modify codes to mitigate this issue based on above suggestions.
Assessed type
Context