DeFi Smart Contract Vulnerabilities Audit Guide

Here are three common DeFi smart contract vulnerabilities, along with specific detection methods used by security auditors and automated tools:

1. Reentrancy Attacks

Description:

Reentrancy occurs when a smart contract calls an external contract (e.g., sending ETH or tokens) and that external contract has a fallback function that allows it to re-enter the original contract before the first call has completed. This can allow an attacker to drain funds by repeatedly invoking the vulnerable function.

Specific Detection Methods:

• Static Analysis: Use tools like Slither or Mythril to detect functions that perform external calls before updating internal state variables. Look for patterns where call or send is used before state changes (e.g., balances[caller] is not decremented before the call).
• Code Pattern Review: Manually inspect functions that transfer funds. Ensure the Checks-Effects-Interactions pattern is followed: