DeFi Smart Contract Vulnerabilities Audit Guide

Here are three common DeFi smart contract vulnerabilities, along with specific technical methods to detect them.

1. Reentrancy Vulnerability

Description:

Reentrancy occurs when a smart contract makes an external call (e.g., sending ETH to another address) before updating its internal state. An attacker can exploit this by invoking the same function again from within the external call, effectively "re-entering" the contract before the state is updated. This allows the attacker to drain funds multiple times.

Specific Detection Methods:

• Static Analysis Tools: Use tools like Slither, Mythril, or Securify to identify state-changing operations that occur after external calls. These tools flag patterns where call (or transfer/send) is used before balance[addr] or other state variables are updated.
• Code Pattern Inspection: Look for the Checks-Effects-Interactions (CEI) pattern