Submitted by leastwood
The TwapOracle.consult() function iterates over all token pairs which belong to either VADER or USDV` and then calculates the price of the respective asset by using both UniswapV2 and Chainlink price data. This helps to further protect against price manipulation attacks as the price is averaged out over the various registered token pairs.
Lets say we wanted to query the price of USDV, we would sum up any token pair where USDV == pairData.token0.
The sum consists of the following:
Consider the following example:
However, the protocol calculates it as (sumUSD * token.decimals()) / sumNative which gives us a SUSHI^2 / (USD*USDV) denominated result. This seems incorrect.
Id classify this issue as high risk as the oracle returns false results upon being consulted. This can lead to issues in other areas of the protocol that use this data in performing sensitive actions.
https://github.com/code-423n4/2021-11-vader/blob/main/contracts/twap/TwapOracle.sol#L115-L157
Similar working implementation listed below:
Manual code review.
To calculate the correct consultation of a given token, the result should return sumUSD * token.decimals() * sumNative instead to ensure the target token to consult is denominated in USD and contains the correct number of decimals.
SamSteinGG (Vader) confirmed:
