DeFi Smart Contract Vulnerabilities Audit Guide

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

1. Reentrancy Attacks

Description:

A reentrancy attack occurs when a smart contract makes an external call to another contract (or itself) before completing its state changes. An attacker can exploit this by calling the vulnerable function again during the external call, before the original function has updated the state (e.g., before reducing the user’s balance). This allows the attacker to drain funds multiple times.

How to Detect:

• Static Analysis Tools: Use tools like Slither, Mythril, or Securify to scan for functions that make external calls (call, delegatecall, send) before modifying critical state variables (e.g., balanceOf[msg.sender] -= amount).
• Code Pattern Inspection: Look for the “Checks-Effects-Interactions” pattern. If state changes (effects) are