DeFi Smart Contract Vulnerabilities Audit Guide

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

1. Reentrancy Attacks

Description:

Reentrancy occurs when a smart contract makes an external call (e.g., sending ETH or ERC-20 tokens) before updating its internal state. An attacker can exploit this by using a malicious fallback function to re-enter the contract before the state update completes, allowing them to withdraw funds multiple times.

Specific Detection Methods:

• Static Analysis Tools: Use tools like Slither (by Trail of Bits) or Mythril. These tools automatically flag functions that perform external calls (call, transfer, send) before state variable updates.
  • Slither Example: Look for warnings like reentrancy-eth or reentrancy-no-eth.
• Code Pattern Inspection:
  • Check for the **"Checks-Effects-Inter