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Submission Details
Severity: medium
Valid

`Chainlink` oracle returns stale price due to `CHAINLINK_TIMEOUT` variable in `LibChainlinkOracle` being set to 4 hours

bube

Summary

The LibChainlinkOracle library utilizes a CHAINLINK_TIMEOUT constant set to 14400 seconds (4 hours). This duration is four times longer than the Chainlink heartbeat that is 3600 seconds (1 hour), potentially introducing a significant delay in recognizing stale or outdated price data.

Vulnerability Details

The LibChainlinkOracle::checkForInvalidTimestampOrAnswer function accepts three input arguments: timestamp, answer and currentTimestamp and check if the return answer from Chainlinlink Oracle or the timestamp is invalid:

​
function checkForInvalidTimestampOrAnswer(
uint256 timestamp,
int256 answer,
uint256 currentTimestamp
) private pure returns (bool) {
// Check for an invalid timeStamp that is 0, or in the future
if (timestamp == 0 || timestamp > currentTimestamp) return true;
// Check if Chainlink's price feed has timed out
if (currentTimestamp.sub(timestamp) > CHAINLINK_TIMEOUT) return true;
// Check for non-positive price
if (answer <= 0) return true;
}
​

The function also checks if the difference between the currentTimestamp and the timestamp is greater then CHAINLINK_TIMEOUT. The CHAINLINK_TIMEOUT is defined to be 4 hours:

​
uint256 public constant CHAINLINK_TIMEOUT = 14400; // 4 hours: 60 * 60 * 4
​

Impact

The Chainlink heartbeat indicates the expected frequency of updates from the oracle. The Chainlink heartbeat on Ethereum for Eth/Usd is 3600 seconds (1 hour).

https://docs.chain.link/data-feeds/price-feeds/addresses?network=ethereum&page=1&search=0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419

But the defined CHAINLINK_TIMEOUT in the LibChainlinkOracle is 14400 seconds (4 hours).

A CHAINLINK_TIMEOUT that is significantly longer than the heartbeat can lead to scenarios where the LibChainlinkOracle library accepts data that may no longer reflect current market conditions. Also, in volatile markets, a 4-hour window leads to accepting outdated prices, increasing the risk of price slippage.

Tools Used

Manual Review

Recommendations

Consider reducing the CHAINLINK_TIMEOUT to align more closely with the Chainlink heartbeat on Ethereum, enhancing the relevance of the price data.

Updates

Lead Judging Commences

giovannidisiena Lead Judge over 1 year ago
Submission Judgement Published
Validated
Assigned finding tags:

Oracle timeout

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