DeFi Smart Contract Vulnerabilities Audit Guide

Here are three of the most common and dangerous DeFi smart contract vulnerabilities, along with specific detection methods for each:

1. Reentrancy Vulnerability

Description:

Reentrancy occurs when a contract makes an external call to another contract before its internal state is fully updated. If the external contract (or a malicious one) can call back into the original contract during this interim state, it can re-execute vulnerable functions, leading to unauthorized withdrawals or state corruption.

How to Detect It:

• Static Analysis with Control Flow Graphs (CFG): Use tools like Slither or Mythril to identify sequences where an external call (e.g., transfer(), call()) occurs before state variables (e.g., balances) are updated. Look for patterns like:

solidity
  // Vulnerable pattern
  require(userBalance[caller] >= amount);
  (bool success, ) = caller.call