DeFi Smart Contract Vulnerabilities Audit Guide

Here are three common DeFi smart contract vulnerabilities, along with specific methods for detecting them during code audits or automated static analysis.

1. Reentrancy Attacks

Vulnerability Description:

A reentrancy attack occurs when a smart contract calls an external contract and does not update its internal state before the call. If the external contract is malicious, it can re-enter the vulnerable function before the original transaction completes, repeatedly draining funds or altering state.

Specific Detection Methods:

• Static Analysis Tools: Use tools like Slither, Mythril, or Echidna to flag functions that make external calls (call, delegatecall, send) before state changes. For example, Slither’s reentrancy-eth detector specifically checks for this pattern.
• Control-Flow Graph (CFG) Inspection: Manually inspect the control flow of external-facing functions. Look for sequences where:
  1. An external call is made.