DeFi Smart Contract Vulnerabilities Audit Guide

Here are three of the most common and damaging DeFi smart contract vulnerabilities, along with specific technical methods to detect them.

1. Reentrancy

Description:

Reentrancy occurs when a smart contract calls an external contract, which in turn calls back into the original contract before the initial transaction has completed. This allows an attacker to re-enter the vulnerable function and manipulate state variables (like balances) before they are updated.

Specific Detection Methods:

• Static Analysis with Control Flow Graphs (CFG): Use tools like Slither or MythX to identify functions that:
  1. Make external calls (e.g., transfer, call, delegatecall).
  2. Modify state variables after the external call.
  3. Rule of Thumb: Enforce the Checks-Effects-Interactions pattern. State changes must occur before any external calls.
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