DeFi Smart Contract Vulnerabilities Audit Guide

Here are three of the most common and critical DeFi smart contract vulnerabilities, along with specific detection methods for each.

1. Reentrancy Attacks

Description:

A reentrancy attack occurs when a smart contract makes an external call to another contract (or the same contract) before updating its internal state. An attacker can recursively re-enter the vulnerable function before the state update is complete, allowing them to drain funds or manipulate state.

How to Detect:

• Static Analysis Tools: Use tools like Slither, Mythril, or Securify to scan for patterns where external calls (e.g., transfer(), call()) occur before state variable updates.
  • Example flag: "External call to an address before writing to a state variable."
• Code Pattern Review: Look for functions that:
  1. Make an external call (e.g., `token.transfer(address payable msg.sender,