DeFi Smart Contract Vulnerabilities Audit Guide

Here are three common DeFi smart contract vulnerabilities, along with specific detection methods for each:

1. Reentrancy Attacks

Vulnerability Description:

Reentrancy occurs when a contract calls an external contract (e.g., transferring ETH or tokens) before updating its own internal state. An attacker can exploit this to recursively call the vulnerable function before the state change is completed, draining funds. This was famously exploited in the 2016 DAO hack.

Specific Detection Methods:

• State-Change-After-External-Call Pattern: Use static analysis tools (e.g., Slither, Mythril) or manual code review to identify functions that:
  1. Modify state variables (e.g., userBalance[msg.sender]).
  2. Make external calls (e.g., msg.sender.transfer(amount) or call{value: amount}("")).
  3. Do not update the