FV-SOL-4 Bad Access Control

TLDR

Improper access control can let unauthorized users access or modify restricted functionality

Code

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract BadAccessControl {
    address public owner;

    constructor() {
        owner = msg.sender;
    }

    function deposit() public payable {}

    function withdraw() public {
        // No access control here, anyone can call this
        payable(msg.sender).transfer(address(this).balance);
    }
}

Classifications

Usig tx.origin for authorization (FV-SOL-4-C1)

tx.origin is a global variable in Solidity that returns the original external account (EOA) that initiated the transaction, even if there are intermediate contracts involved. It’s often tempting to use tx.origin for access control, thinking it securely identifies the initiator of the transaction. However, it introduces serious security risks due to its susceptibility to phishing attacks through intermediary contracts

Unrestricted Role Assignment (FV-SOL-4-C2)

If a function to set an owner or assign roles is public or lacks access control, anyone can call it, potentially taking control of the contract

Lack of Multi-Signature for Crucial Operations (FV-SOL-4-C3)

if a critical function (like transferring large funds or changing important contract settings) is controlled by a single address (usually the contract owner), it creates a single point of failure

Mitigation Patterns

Ownership Pattern (FV-SOL-4-M1)

The ownership pattern restricts critical functions to the contract owner, usually set during contract deployment. This is commonly achieved with an onlyOwner modifier

Proper RBAC (FV-SOL-4-M2)

Role-Based Access Control allows defining multiple roles, each with specific permissions. For example, roles like Admin, Minter, or Pauser can be created, allowing more granular control

Multi-Signature Approval (FV-SOL-4-M3)

Multi-sig patterns require multiple accounts to approve a critical action before it can be executed. This reduces the risk of unauthorized actions due to a compromised account

Actual Occurrences

• https://solodit.cyfrin.io/issues/h-02-eth-gets-locked-in-the-groupcoinfactory-contract-pashov-audit-group-none-groupcoin-markdown

Content