DeFi Smart Contract Vulnerabilities Audit Guide

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

1. Reentrancy Vulnerability

Description:

Reentrancy occurs when a smart contract calls an external contract (e.g., sending ETH to a user) before updating its own internal state (e.g., debit balances). A malicious user can exploit this by triggering the external call recursively, repeatedly draining funds before the state is updated.

Specific Detection Methods:

• State Update Order Check: Verify that all state variable updates (e.g., balanceOf[user] -= amount) occur before any external function calls (e.g., address payable(user).call{value: amount}("")). Tools like Slither or Mythril flag patterns where external calls precede state changes.
• Access Control on External Calls: Ensure that functions performing external calls are protected by nonReentrant modifiers (