Lines of code

https://github.com/code-423n4/2024-08-phi/blob/main/src/abstract/RewardControl.sol#L100

Vulnerability details

Impact

Withdrawals can be replayed in multiple chains because of the absence of chain.id in the signature .

Proof of Concept

The withdrawWithSig is for withdrawing funds with a signature :

 function withdrawWithSig(address from, address to, uint256 amount, uint256 deadline, bytes calldata sig) external {
        if (block.timestamp > deadline) revert DeadlineExpired();
        if (!_verifySignature(from, to, amount, nonces[from], deadline, sig)) revert InvalidSignature();//@audit chain.id not included, makes it vulnerable to replay attacks ! 
        unchecked {
            ++nonces[from];
        }
        _withdraw(from, to, amount);
    }

Phi protocol will be deployed in multiple chains . If a user has balances in different chains and signs a withdrawal to a person , If the nonces are same in both chains , the withdrawal can be replayed in all deployed chains .

Main issue here is the absense of chain.id in the signature .

Tools Used

Manual Review !

Recommended Mitigation Steps

Include chain.id in the signature to be replay proof !

Assessed type

Context

code-423n4 / 2024-08-phi-validation

withdrawals can be replayed in different chain ! #602