Ocean_Sky - If Price falls to zero, liquidations will be frozen

[sherlock-admin]

Ocean_Sky

medium

If Price falls to zero, liquidations will be frozen

Summary

Liquidation function won't work if the price falls to zero.

Vulnerability Detail

Zero is unacceptable value when retrieving price from chainlink oracle. So if the price falls to zero, the liquidation process won't be triggered or simply "frozen" (all calls will revert). If this happens, collateral assets won't be liquidated and the protocol will be insolvent.

Similar case issues:
sherlock-audit/2023-02-blueberry-judging#161
sherlock-audit/2023-02-gmx-judging#156

Impact

Liquidations may not be possible at a time when the protocol needs them most. As a result, the value of user's asset may fall below their debts, turning off any liquidation incentive and pushing the protocol into insolvency.

Code Snippet

https://github.com/sherlock-audit/2023-05-ironbank/blob/main/ib-v2/src/protocol/oracle/PriceOracle.sol#L60-#L72
https://github.com/sherlock-audit/2023-05-ironbank/blob/main/ib-v2/src/protocol/pool/IronBank.sol#L1065-#L1092

Tool used

Manual Review

Recommendation

Provide safeguard mechanism to avoid this from happening.

Duplicate of #433