Alchemix Transmuter

Summary

A malicious actor could manipulate the StrategyMainnet::availableWithdrawLimit, StrategyArb::availableWithdrawLimit and StrategyOp::availableWithdrawLimit by depositing the asset token into the strategy contract.

Vulnerability Details

The protocol has a availableWithdrawLimit function in all three contracts, which allows the protocol / anyone to view the current available withdrawal limit.

However, due to the use of balanceOf(address(this)), it makes the contract susceptible to donation attack, manipulating the current available withdrawal limit.
The natspec suggests that this function will be called before any withdraw or redeem.

Impact

This function is likely to be used by protocol, protocol's keeper and users, returning a false value could hinder the operations of the off-chain mechanim of the protocol.

Tools Used

Manual Review

Recommendations

It is recommmended to directly fetch values from the transmuter itself.