DeFi Smart Contract Vulnerabilities Audit Guide

Here are three common DeFi smart contract vulnerabilities, along with specific technical methods to detect them.

1. Reentrancy Attacks

Description:

An attacker exploits a function that makes an external call to another contract (e.g., sending ETH) before updating the internal state (e.g., user balance). If the external contract is malicious, it can re-enter the vulnerable function during the call, allowing the attacker to drain funds multiple times.

Specific Detection Methods:

• Static Analysis for State-Calls-State Pattern: Use tools like Slither or Mythril to scan for functions where msg.sender receives funds (via call, transfer, or send) before the contract’s state variables (e.g., balances[msg.sender]) are updated. Example flag:

solidity
  // Vulnerable pattern:
  function withdraw() public {
      uint256