Summary

The transferFrom function in the StabilityBranch.sol contract allows an arbitrary address to be used as the from parameter. This design flaw opens the potential for unauthorized token transfers, as it does not enforce proper authorization checks. This vulnerability can lead to loss of funds and breaches of trust among token holders. It is critical to restrict the from parameter to msg.sender to ensure transfers are only initiated by authorized entities.

Vulnerability Details

Description

The ERC20 transferFrom function is utilized on line 409 of StabilityBranch.sol. However, the function does not enforce that msg.sender must be the from parameter. Instead, it permits an arbitrary address, allowing malicious actors to transfer tokens from another user's address without proper approval.

Code Example

Since the from parameter is not restricted to msg.sender, an attacker can exploit this to bypass authorization checks and perform unauthorized token transfers.

Impact

• Unauthorized Token Transfers: Malicious actors can transfer tokens from a user's address without approval.

• Loss of Funds: Token holders may lose their funds without their consent or knowledge.

• Security Breach: This vulnerability undermines the integrity of the token transfer mechanism, resulting in a loss of trust among users.

Tools Used

1. Remix IDE: For reviewing the specific line of code and analyzing the function's behavior.

2. Slither: To detect improper parameter usage in the transferFrom function.

3. MythX: For identifying token authorization vulnerabilities in the contract.

Recommendations

Enforce msg.sender as the from Parameter:
Ensure that the from parameter in the transferFrom function is restricted to msg.sender to prevent unauthorized transfers.

• Add Proper Authorization Checks:
  If a custom authorization flow is needed, implement explicit checks to validate the from address before allowing the transfer. For example:

  require(from == msg.sender, "Unauthorized transfer attempt");

  ​

• Audit All transferFrom Usages:
  Conduct a thorough review of all instances of transferFrom in the codebase to ensure similar vulnerabilities do not exist elsewhere.

• Use Role-Based Access Control (RBAC):
  Implement role-based access control to limit who can call functions involving transferFrom. Use libraries like OpenZeppelin's AccessControl for efficient role management.

• Testing and Verification:
  Write unit tests to verify that only authorized entities can initiate transfers using the transferFrom function.