DeFi Smart Contract Vulnerabilities Audit Guide

Here are three common DeFi smart contract vulnerabilities, along with specific detection methods for each:

1. Reentrancy Attacks

Description:

An attacker calls a function that sends Ether (or another token) to another contract. If the target contract does not update its internal state before making the external call, the attacker can recursively call the same function before the state is updated, draining funds.

Specific Detection Methods:

• Control Flow Analysis (CFA): Use static analysis tools (e.g., Slither, Mythril) to detect patterns where an external call (call, delegatecall, transfer, or send) occurs before a state variable update that depends on the caller’s balance.
  • Example pattern:

solidity
    // Vulnerable pattern
    require(balances[msg.sender] >= amount);
    (bool success, ) = msg.sender.call{value: amount}("");