DeFi Smart Contract Vulnerabilities Audit Guide

Here are three of the most common and high-impact DeFi smart contract vulnerabilities, along with specific detection methods:

1. Reentrancy Attacks

Description:

An attacker calls a contract function that sends ETH or tokens to an external address (or another contract). If the external call is made before the contract’s internal state is updated, the recipient can re-enter the same function during the external call, bypassing checks (e.g., balance checks) and draining funds.

Specific Detection Methods:

• Static Analysis: Use tools like Slither or Mythril to detect functions that perform external calls (.call(), transfer(), send()) before state changes (e.g., updating balances, flags). Look for the pattern:

solidity
  // Vulnerable pattern
  function withdraw() public {
      address recipient = msg.sender;
      uint256 amount = balances[recipient