DeFi Smart Contract Vulnerabilities Audit Guide

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

1. Reentrancy Attacks

Description:

Reentrancy occurs when a smart contract makes an external call to an untrusted contract before updating its internal state. An attacker can exploit this by deploying a malicious contract that, upon receiving the external call, recursively calls the vulnerable function again before the original transaction completes. This allows the attacker to drain funds multiple times in a single transaction.

Specific Detection Methods:

• Static Analysis Tools: Use tools like Slither or Mythril to automatically detect functions that perform external calls without state updates. Look for warnings related to "reentrancy" or "external calls before state updates."
• Code Pattern Review: Manually inspect any function that:
  1. Checks a balance or allowance.
  2. Makes an external call (e.g., `transfer