First Flight #9: Soulmate

Summary

Vault.initVault(ILoveToken loveToken, address managerContract) can be frontrun

Vulnerability Details

In 2 contracts Vault (one for airdrop and one for staking)
function initVault(ILoveToken loveToken, address managerContract) can be frontrun by malicious user which leads to stolen all funds from loveToken contract.

POC

1 Solmate team deploy LoveToken contract.
2 Solmate team deploy Vault for airdrop or staking.
3 Solmate team calls initVault(ILoveToken loveToken, address managerContract).
4 Attacker is constantly scanning the mempool for initVault(ILoveToken loveToken, address managerContract) function calls.
5 Attacker detects a initVault(ILoveToken loveToken, address managerContract) function call in the mempool.
6 Attacker frontruns the initVault(ILoveToken loveToken, address managerContract) call with the LoveToken address as loveToken input parameter and his address as a managerContract input parameter.
7 Attacker calls LoveToken.transferFrom with:

• from input parameter equal Vault address,

• to input parameter equal address controlled by the attacker,

• amount input parameter equal 500_000_000 ether.

Tools Used

Manual review.

Recommendations

Implement access control for Vault.initVault(ILoveToken loveToken, address managerContract) to ensure only the relevant deployer can call Vault.initVault(ILoveToken loveToken, address managerContract).