DeFi Smart Contract Vulnerabilities Audit Guide

Here are three of the most common and dangerous DeFi smart contract vulnerabilities, along with specific methods and tools to detect them.

1. Reentrancy Attacks

Description:

A reentrancy attack occurs when a contract calls an external contract before updating its own internal state. If the external contract is malicious, it can re-enter the vulnerable function before the state change is recorded, allowing the attacker to drain funds repeatedly.

Specific Detection Methods:

• Static Analysis with Slither: Run slither . in your project directory. Slither flags functions that perform external calls before state changes. Look for warnings like "reentrancy-eth" or "reentrancy-benign".
• Pattern Matching for "Checks-Effects-Interactions" (CEI) Violation: Manually review all functions that transfer ETH or tokens. Ensure the order is:
  1. Checks: Validate access control and