DeFi Smart Contract Vulnerabilities Audit Guide

Here are three of the most common and critical 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 makes an external call to another contract (or itself) before updating its internal state. An attacker can exploit this by recursively calling the vulnerable function before the state variable is updated, allowing them to drain funds or manipulate state multiple times.

Common Vulnerable Pattern:

function withdraw(uint amount) public {
    require(balances[msg.sender] >= amount);
    (bool success, ) = msg.sender.call{value: amount}(""); // External call BEFORE state update
    require(success);
    balances[msg.sender] -= amount; // State updated AFTER external call
}

How to Detect It:

• Static Analysis Tools: Use tools like Slither or **Myth