DeFi Smart Contract Vulnerabilities Audit Guide

Here are three common DeFi smart contract vulnerabilities, along with specific detection methods using static analysis, formal verification, and manual auditing techniques.

1. Reentrancy Attacks

Description:

A reentrancy attack occurs when a smart contract calls an external contract (e.g., a user’s wallet or another DeFi protocol) and that external contract calls back into the vulnerable function before the first call has completed. This allows an attacker to repeatedly drain funds by manipulating state variables (such as balances) before they are updated.

How to Detect:

• Static Analysis with Control Flow Graphs (CFG): Use tools like Slither (by Trail of Bits) or Mythril to identify external calls that occur before state variable updates. Look for patterns where:
  • An external call (call, send, or transfer) is made.
  • A state variable (e.g., balances[msg.sender]) is