DeFi Smart Contract Vulnerabilities Audit Guide

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

1. Reentrancy Vulnerability

Description:

Reentrancy occurs when a contract calls an external contract (or itself) before completing its state updates. An attacker can exploit this by repeatedly calling the vulnerable function before the state is fully updated, allowing them to drain funds multiple times. This is famously seen in the 2016 DAO hack.

Specific Detection Methods:

• State-Change-After-External-Call Pattern: Use static analysis tools (e.g., Slither, Mythril) to flag functions where:
  1. state variable is read or modified.
  2. An external function call (contract.method()) is made.
  3. state variable is modified after the external call.
  4. Example Flag: `balance[msg