Submission Details
Impact:
Likelihood:
Incorrect Collateral Calculation During Unwind Operation
Author Revealed upon completion
// Current calculation in _executeUnwindOperation
uint256 collateralToWithdraw = (
_amount * debtTokenPrice * (10 ** IERC20(unwindParams.collateralToken).decimals()) * LTV_PRECISION
) / (collateralTokenPrice * (10 ** IERC20(_asset).decimals()) * liqThreshold);
// @> liqThreshold should be ltv
Description
Normal behavior: The contract should calculate the exact amount of collateral to withdraw to repay the debt plus flash loan when unwinding a leveraged position.
Issue: The contract currently uses liquidationThreshold instead of the correct LTV for calculating how much collateral to withdraw. This results in underestimation of collateral, causing insufficient repayment for the flash loan.// Root cause in the codebase with @> marks to highlight the relevant section
Risk
Likelihood:
-
Reason 1 // Describe WHEN this will occur (avoid using "if" statements)
-
Reason 2
Impact:
-
Impact 1
-
Impact 2
Proof of Concept
Open a leveraged position using Aave.
Attempt to unwind using the contract.
Observe that the swap returns less than required to cover the flash loan.
Recommended Mitigation
- uint256 collateralToWithdraw = (
- _amount * debtTokenPrice * (10 ** IERC20(unwindParams.collateralToken).decimals()) * LTV_PRECISION
- ) / (collateralTokenPrice * (10 ** IERC20(_asset).decimals()) * liqThreshold);
+ (, uint256 ltv,,,,,,,,) = aaveDataProvider.getReserveConfigurationData(unwindParams.collateralToken);
+ uint256 collateralToWithdraw = (
+ _amount * debtTokenPrice * (10 ** IERC20(unwindParams.collateralToken).decimals()) * LTV_PRECISION
+ ) / (collateralTokenPrice * (10 ** IERC20(_asset).decimals()) * ltv);
Rewards breakdown
nSLOC
356This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
Live
The contest is live. Earn rewards by submitting a finding.
Appeals
This is your time to appeal against judgements on your submissions.
Appeals Review
Appeals are being carefully reviewed by our judges.
Rewards Distribution
The contest is complete and the rewards are being distributed.