Naught Coin

Transfer all your initial Naught Coins to another address, bypassing the transfer lock.

Vulnerable Code

Analyze the Solidity code below to find the vulnerability.

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

import '@openzeppelin/contracts/token/ERC20/ERC20.sol';

// Simple ERC20 token with a time lock on transfers for the initial owner
contract NaughtCoin is ERC20 {

  uint public timeLock;
  address public player; // The initial owner/player

  // Modifier to lock transfers for the player until timeLock expires
  modifier lock() {
    if (msg.sender == player) {
      require(block.timestamp > timeLock, "Tokens are locked for the player");
    }
    _; // Continue execution
  }

  constructor(address _player) ERC20('NaughtCoin', '0g') {
      player = _player;
      // Lock tokens for 10 years initially
      timeLock = block.timestamp + 10 * 365 days;
    // Mint initial supply to the player
    _mint(player, 1000000 * (10**18));
  }

  // Override the standard transfer function to add the lock modifier
  function transfer(address _to, uint256 _amount) public override lock returns (bool) {
      return super.transfer(_to, _amount);
  }

  // Allow approve and transferFrom without the lock modifier
  // These standard ERC20 functions are inherited and NOT overridden with the lock.
}

Submit Explanation

Explain the vulnerability and how to exploit it.

Your Explanation

Hints (3)

Just a little peak

Hint 1

Hint 2

Hint 3

Explanation

Discomfort = Learning

Naught Coin

Unveil Explanation