DeFi Smart Contract Vulnerabilities Audit Guide

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

1. Reentrancy Attacks

Vulnerability:

An attacker exploits the fact that external calls (e.g., transferring ERC-20 tokens) can trigger callbacks into the same contract before the state variables are updated. This allows the attacker to re-enter the vulnerable function multiple times, draining funds.

Specific Detection Methods:

• Static Analysis: Use tools like Slither or Mythril to detect functions that make external calls before updating internal state variables (violating the "Checks-Effects-Interactions" pattern).
  • Example: Look for functions where transfer() or transferFrom() is called before balanceOf[msg.sender] is decremented.
• Dynamic Testing: Write fuzz tests that simulate an attacker contract calling the vulnerable function repeatedly during an ETH/token transfer. Verify if the balance changes reflect only one legitimate