DeFi Smart Contract Vulnerabilities Audit Guide

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

1. Reentrancy Attack

Description:

Reentrancy occurs when a contract makes an external call to another contract (or itself) before updating its internal state. If the external contract is malicious, it can re-enter the vulnerable function before the state update is complete, allowing an attacker to drain funds multiple times. This was famously exploited in the 2016 DAO hack.

How to Detect It:

• Static Analysis Tools: Use tools like Slither, Mythril, or Securify. These tools analyze the code for patterns where external calls (call, delegatecall) occur before state variable changes.
  • Example Slither command: slither . --detect reentrancy-eth
• Manual Code Review Pattern: Look for the **Checks-Effects-Inter