DeFi Smart Contract Vulnerabilities Audit Guide

Here are three of the most common and impactful DeFi smart contract vulnerabilities, along with specific detection methods.

1. Reentrancy Attacks

Vulnerability Description:
Reentrancy occurs when a smart contract calls an external contract (e.g., a user’s wallet or another token contract) before updating its own state. An attacker can exploit this by embedding malicious logic in the external contract’s receive or fallback function, which re-enters the vulnerable function before the original call completes. This allows the attacker to withdraw funds multiple times before the balance is updated.

Common Scenario:

• A withdraw() function sends ETH to a user via address payable(user).transfer(amount) before decrementing the user’s balance in the contract’s mapping.

How to Detect:

1. Static Analysis Tools:
   • Use tools like Slither, Mythril, or Securify. They