sherlock-audit / 2023-02-kairos-judging

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curiousapple - The liquidation payout could be considered unfair for lenders with higher LTV. #180

Closed sherlock-admin closed 1 year ago

sherlock-admin commented 1 year ago

curiousapple

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The liquidation payout could be considered unfair for lenders with higher LTV.

Summary

The liquidation payout could be considered unfair for lenders with higher LTV.

Vulnerability Detail

Kairos distributes interests to lenders in proportion to the amount lent, while liquidation rewards are distributed based on the share provision, presumably to handle borrower claims. However, this approach can lead to interesting scenarios between lenders' and incentivizes lenders to offer lower loan-to-value (LTV) than their peers. This is because they can take less risk but still receive an equal share in the liquidation payout.

Consider Lender A offers an LTV of 20, while Lender B offers an LTV of 10. The borrower borrows 10 from A and 5 from B, resulting in a matched = ONE. If the position is liquidated for 15, both A and B would be rewarded with 7.5.

This approach can be seen as unfair to A, who took considerably more risk and suffered a greater loss (-2.5) compared to B, who gained 2.5 in the end. Therefore, it may be worth considering alternative methods for distributing liquidation rewards that take into account the lenders' risks.

Impact

Liquidation payout is distributed unfairly between lenders.

Code Snippet

https://github.com/sherlock-audit/2023-02-kairos/blob/main/kairos-contracts/src/ClaimFacet.sol#L117

Tool used

Manual Review

Recommendation

Consider alternative methods for distributing liquidation rewards that take into account the lenders' risks.