DeFi Smart Contract Vulnerabilities Audit Guide

Here are three common DeFi smart contract vulnerabilities, along with specific techniques and tools to detect them.

1. Reentrancy Vulnerability

Description:
Reentrancy occurs when a smart contract calls an external contract (e.g., sending ETH or tokens) before updating its own internal state. If the external contract is malicious, it can recursively call back into the vulnerable function before the state update completes, allowing an attacker to drain funds multiple times using the same state condition.

Specific Detection Methods:

• Static Analysis for "CEI" Violation:
  • Check if functions follow the Checks-Effects-Interactions pattern.
  • Detect: Flag any function where an external call (e.g., call(), send(), transfer()) occurs before state variable updates (e.g., balances[msg.sender] -= amount).
  • Tool: Use Slither, Mythril, or Echid