Summary

The audit has identified unsafe ERC20 operation practices within the TokenManager.sol contract, where standard ERC20 functions are used directly without proper handling of potential failures. This is found on two specific lines of code that do not validate return values or handle possible transfer rejections adequately, thereby posing significant risks to the contract's integrity and security.

Vulnerability Details

Unsafe Transfer to Sender

• Location: src/core/TokenManager.sol, Line 169
  Code: payable(msg.sender).transfer(claimAbleAmount);

• Issue: This direct transfer method does not handle potential failures properly. If transfer fails (e.g., due to the gas limit constraints of 2300 inherent to transfer), the contract will not properly mitigate these issues, potentially leaving the contract in an inconsistent state or causing loss of funds.

Unsafe Approval Handling

• Location: src/core/TokenManager.sol, Line 247
  Code: ICapitalPool(\_capitalPoolAddr).approve(address(this));

• Issue: The success of the approve call is not checked, which may result in assumptions that are incorrect regarding the current approval status. This can potentially lead to failed or unintended token movements which compromise the intended contract logic and security.

Impact

The identified issues can result in:

• Potential loss of funds if transfers fail without being detected.

• Erroneous contract behaviors due to unchecked approval statuses.

• Inconsistent contract states that increase vulnerability to further exploits.

Tools Used

Manual Code Review

Recommendations

To address these issues, it is highly recommended to utilize OpenZeppelin's SafeERC20 library which ensures that ERC20 operations (transfer, approve) are safely executed and automatically handle any failure states.

Specific Recommendations:

1. Replace Direct Transfers with Safe Methods:

   (bool success, ) = payable(msg.sender).call{value: claimAbleAmount}("");

   require(success, "Transfer failed.");

   ​

2. Use Safe Approval Methods Provided by SafeERC20:

   SafeERC20.safeApprove(IERC20(_tokenAddress), address(this), _amount);