DeFi Smart Contract Vulnerabilities Audit Guide

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

1. Reentrancy

Description:

Reentrancy occurs when a smart contract makes an external call to another contract (e.g., sending ETH) before its internal state is fully updated. An attacker can exploit this by writing a malicious fallback() or receive() function that re-enters the vulnerable function before the first transaction completes, allowing them to drain funds multiple times.

Specific Detection Methods:

• Static Analysis (Control Flow Graph Analysis): Use tools like Slither or Mythril to detect patterns where an external call (call, delegatecall, send) occurs before a state variable update (e.g., balances[msg.sender] -= amount). Example Slither rule: reentrancy-eth or reentrancy-benign. -