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Contract Name
DeFi Token Contract
Security Score
78/100
Total Findings
5
Code Lines
450 lines
CRITICAL
1
HIGH
1
MEDIUM
2
LOW
1
Lines 45-48 in Token.sol
function initialize(address _owner) public {
owner = _owner;
initialized = true;
}Missing access control allows anyone to call this function
function initialize(address _owner) public {
require(!initialized, "Already initialized");
require(msg.sender == deployer, "Not authorized");
owner = _owner;
initialized = true;
}Fix Explanation:
Added checks to ensure the function can only be called once and only by the authorized deployer
An attacker could call initialize() with their own address, becoming the owner and gaining full control of the contract including the ability to mint tokens or drain funds.
Always protect initialization functions with proper access controls. Use OpenZeppelin's Initializable pattern for upgradeable contracts.
Lines 120-125 in Token.sol
function withdraw(uint256 amount) public {
require(balances[msg.sender] >= amount);
(bool success, ) = msg.sender.call{value: amount}("");
require(success);
balances[msg.sender] -= amount;
}State is updated after external call, violating checks-effects-interactions pattern
function withdraw(uint256 amount) public nonReentrant {
require(balances[msg.sender] >= amount);
balances[msg.sender] -= amount; // Update state first
(bool success, ) = msg.sender.call{value: amount}("");
require(success);
}Fix Explanation:
Updated state before external call and added nonReentrant modifier to prevent reentrancy attacks
An attacker could create a malicious contract that calls withdraw() recursively before the balance is updated, draining more funds than they own.
Always follow the checks-effects-interactions pattern. Update state before making external calls and use OpenZeppelin's ReentrancyGuard.
Lines 85-90 in Token.sol
function transfer(address to, uint256 amount) public {
require(balances[msg.sender] >= amount);
balances[msg.sender] -= amount;
balances[to] += amount;
}No validation for zero address, tokens could be permanently lost
function transfer(address to, uint256 amount) public {
require(to != address(0), "Cannot transfer to zero address");
require(balances[msg.sender] >= amount, "Insufficient balance");
balances[msg.sender] -= amount;
balances[to] += amount;
emit Transfer(msg.sender, to, amount);
}Fix Explanation:
Added zero address check and proper error messages, plus Transfer event emission
Users could accidentally send tokens to the zero address, permanently burning them without intention.
Always validate input parameters, especially addresses. Add events for important state changes.