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 during code audits or development.

1. Reentrancy Attacks

Description:

A reentrancy attack occurs when a smart contract calls an external contract (e.g., another wallet or DeFi protocol) before updating its own internal state. If the external contract is malicious, it can re-enter the vulnerable function within the same transaction, exploiting the un-updated state to drain funds. The classic "check-effects-interactions" pattern failure is the root cause.

How to Detect:

• Static Analysis with Slither: Use Slither (a static analysis tool for Solidity) to look for the reentrancy detection flag. It flags functions that make external calls (call, send, delegatecall) without updating state variables first.

  slither . --detect reentrancy