DeFi Smart Contract Vulnerabilities Audit Guide

Here are three common DeFi (Decentralized Finance) smart contract vulnerabilities, along with specific detection methods and tools used to identify them.

1. Reentrancy Attacks

Description:

A reentrancy attack occurs when a smart contract calls an external contract (e.g., sending ETH to a user) and does not update its internal state before the external call. The external contract can then re-enter the vulnerable function multiple times before the state is updated, allowing an attacker to drain funds.

Example:

A withdraw() function sends ETH to a user but updates the user’s balance after the transfer. An attacker’s contract can repeatedly call withdraw() in the fallback function, draining the entire pool.

Detection Methods:

• Static Analysis Tools:
  • Slither (by Trail of Bits): Automatically detects reentrancy by analyzing call ordering. Look for warnings like reentrancy-eth or `