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:

A reentrancy attack occurs when a contract calls an external contract (e.g., transferring ETH) before updating its own internal state (e.g., updating user balances). An attacker can exploit this by recursively calling the vulnerable function from the external contract’s callback (via call or delegatecall), allowing them to drain funds before the state is updated.

Specific Detection Methods:

• Static Analysis Tools:
  • Slither: Run slither . to detect unbounded loops or external calls before state changes. It flags patterns like ETH transfer → state update without a reentrancy guard.
  • Mythril: Use mythril . to perform symbolic execution. It can model attacker-controlled inputs and identify paths where a re