🚀 Top 10 Smart Contract Vulnerabilities in Startups 📉

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The rise of decentralized apps has made smart contracts more critical than ever. Yet, many startups inadvertently introduce vulnerabilities. Here are 10 common pitfalls:

  1. Reentrancy:
    • Exploit: External calls can run arbitrary code, allowing repeated withdrawals.
    • Prevent: Use the checks-effects-interactions pattern.
  2. Arithmetic Over/Underflows:
    • Exploit: Unsafely incrementing/decrementing can reset a variable.
    • Prevent: Use safe math libraries.
  3. Unchecked Return Values:
    • Exploit: Ignored outputs may lead to unhandled exceptions.
    • Prevent: Always handle external call outcomes.
  4. Timestamp Dependence:
    • Exploit: Miners can manipulate timestamps.
    • Prevent: Avoid critical operations based on block timestamp.
  5. Access Control:
    • Exploit: Insufficient restrictions give attackers permissions.
    • Prevent: Properly set & frequently audit contract permissions.
  6. Outdated Compiler:
    • Exploit: Old compilers may have known vulnerabilities.
    • Prevent: Regularly update and check compiler versions.
  7. Immutable Bugs:
    • Exploit: Once deployed, contracts can’t be altered.
    • Prevent: Implement upgrade patterns and thorough testing.
  8. Short Address Attack:
    • Exploit: Manipulate msg.data length to cause errors.
    • Prevent: Always validate the length of msg.data.
  9. Uninitialized Storage Pointers:
    • Exploit: Uninitialized state variables can be overwritten.
    • Prevent: Always initialize state variables.
  10. Denial of Service (DoS):
  • Exploit: Flood contract, making it unusable.
  • Prevent: Implement gas usage limits and anti-spam measures.

🛡️ For a deep dive and examples, visit OurWebsite.com/SmartContractSecurity. Ensure your contract’s security is rock solid!

Reentrancy:

  • Vulnerable:solidity

function withdraw() public { uint amount = balances[msg.sender]; require(msg.sender.call.value(amount)()); balances[msg.sender] = 0; } Hardened:

solidity

  • function withdraw() public { uint amount = balances[msg.sender]; balances[msg.sender] = 0; require(msg.sender.call.value(amount)()); }

Arithmetic Over/Underflows:

  • Vulnerable:solidity

balances[msg.sender] += msg.value; Hardened (Using OpenZeppelin’s SafeMath):

solidity

  • balances[msg.sender] = balances[msg.sender].add(msg.value);

Unchecked Return Values:

  • Vulnerable:solidity

otherContract.execute(); Hardened:

solidity

  • require(otherContract.execute());

Timestamp Dependence:

  • Vulnerable:solidity

if (now >= deadline) {...} Hardened (Avoid reliance):

solidity

  • // Use block number or other reliable mechanisms

Access Control:

  • Vulnerable:solidity

function setOwner(address _newOwner) public { owner = _newOwner; } Hardened:

solidity

  • function setOwner(address _newOwner) public onlyOwner { owner = _newOwner; }
  • Vulnerable: // Allowing unbounded loop iterations or gas consumption
  • Hardened: // Implementing gas checks or breaking up operations

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