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Nexus Intelligence Research
Nexus Intelligence Research

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DeFi Smart Contract Vulnerabilities Audit Guide

Here are three of the most common and critical DeFi smart contract vulnerabilities, along with specific detection methods for each.

1. Reentrancy Attacks

Description:

A reentrancy attack occurs when a contract makes an external call to an untrusted contract before updating its own state. If the external contract is malicious, it can re-enter the vulnerable function before the state change is complete, allowing the attacker to drain funds multiple times.

Example Scenario:

A withdraw() function sends ETH to a user via call.value() but updates the balances[msg.sender] after the send. An attacker contract can repeatedly call withdraw() within the callback, draining the vault.

How to Detect:

  • Static Analysis Tools: Use tools like Slither or Mythril. Slither specifically flags this with checks like reentrancy-eth and reentrancy-benign.

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