DeFi Smart Contract Vulnerabilities Audit Guide

Here are three common DeFi smart contract vulnerabilities, along with specific detection methods and techniques.

1. Reentrancy Attack

Description:

An attacker calls a function in a smart contract that sends Ether to an external address. Before the state of the first call is updated (e.g., before the user’s balance is decreased), the external call triggers a fallback function at the attacker’s address, which re-enters the same vulnerable function. This allows the attacker to drain funds multiple times before the contract’s state is properly updated.

How to Detect:

• Static Analysis Tools:

  • Slither: Use the reentrancy-eth and reentrancy-no-eth detectors. Example:

  slither . --detect reentrancy
  

  • Mythril: Run mythril explore --function-name withdraw --address <contract_address>. Mythril uses symbolic execution