DeFi Smart Contract Vulnerabilities Audit Guide

Here are three of the most common and critical DeFi smart contract vulnerabilities, along with specific methods and tools to detect them.

1. Reentrancy Attacks

Description:

Reentrancy occurs when a smart contract calls an external contract (e.g., via a call or transfer function) before updating its internal state. A malicious contract can exploit this by re-entering the vulnerable function before the state is updated, allowing attackers to drain funds multiple times. This was famously exploited in the 2016 DAO hack.

How to Detect:

• Static Analysis Tools: Use tools like Slither (by Trail of Bits) or Mythril. These tools analyze control-flow graphs to identify "External calls" that occur before "State changes."
  • Example Slither Output: reentrancy-eth or reentrancy-no-eth warnings.
• Code Pattern Inspection: Look for