DeFi Smart Contract Vulnerabilities Audit Guide

Here are three of the most prevalent DeFi smart contract vulnerabilities, along with specific technical methods for detecting them.

1. Reentrancy Attacks

The Vulnerability:
Reentrancy occurs when a contract makes an external call (e.g., transferring ETH to a user) before updating its internal state (e.g., reducing the user's balance). An attacker can exploit this by making a recursive call from the receiving contract back into the vulnerable function before the state update completes, effectively draining the contract’s balance.

How to Detect It:

• Static Analysis (Pattern Matching):
  • Look for the "CEI" (Checks-Effects-Interactions) violation: Identify functions that perform an external call (e.g., call(), transfer(), send()) before modifying state variables that are used in subsequent checks.
  • Use tools like Slither (by Trail of Bits) or