AlexCzm - No check for active Arbitrum Sequencer

[sherlock-admin]

AlexCzm

medium

No check for active Arbitrum Sequencer

Summary

Chainlink recommends that all Optimistic L2 oracles consult the Sequencer Uptime Feed to ensure that the sequencer is live before trusting the data returned by the oracle.

Vulnerability Detail

If the Arbitrum Sequencer goes down, oracle data will not be kept up to date, and thus could become stale. However, users are able to continue to interact with the protocol directly through the L1 optimistic rollup contract.
Even if there is a backup uniswap price feed if no problem is detected, the back up probably will not be used.

As a result, users may be able to use the protocol while oracle feeds are stale.

Impact

If the Arbitrum sequencer goes down, the protocol will allow users to continue to operate at the previous (stale) rates.

Code Snippet

https://github.com/sherlock-audit/2023-04-jojo/blob/6090fef68932b5577abf6b5aa26eb1e579353c57/smart-contract-EVM/contracts/adaptor/chainlinkAdaptor.sol#L43-L55

Tool used

Manual Review

Recommendation

Follow the Chainlink recomandations and use a sequencer uptime feed.

Duplicate of #101