A Developer’s guide to Smart Contract Security Audits

1. A Developer’s guide to Smart Contract Security Audits Cyphershield.tech

2. Smart contract audits enable developers to provide a thorough analysis of smart contract sets. The main goal of a smart contract audit is to detect and eliminate vulnerabilities. • A good smart contract audit examines and comments on a project’s smart contract code, presented to the project’s developers. • One key aspect to remember when writing smart contracts is to keep it simple, as added complexity increases the likelihood of errors • Simplicity in smart contract design is effective in instances where the smart contract system performs a limited set of functions for a predefined period of time. • The security audit of a contract has to start from the development stage, adding new, thorough tests when new attack vectors are discovered • There are pitfalls that have to be considered when programming smart contracts on the Ethereum blockchain, such as how timestamps can be imprecise, with miners influencing the execution time of a transaction.

3. Getting started • First, we’ll audit a smart contract for bulk-uploading NFTs. A key component of auditing smart contracts is the process of investigating aspects of the code to find bugs, vulnerabilities, and risks before deployment to the Ethereum mainnet. • A smart contract audit is not a 100 percent guarantee that the contract won’t exhibit bugs or vulnerabilities. • It does, however, guarantee that the smart contractis secure and has been reviewed by an expert. Structure of a smart contract audit A smart contract audit report is expected to contain a variety of items, listed below, including details about identified vulnerabilities, a disclaimer, and suggested remediations.

4. Disclaimer: This section is important for stating that the audit is not a legally binding document and provides no guarantee • Overview of the audit: A brief look at the contract and the best practices that have been observed in its creation • Attacks carried out on the contract: Outlines the attacks that have been carried out on the contract, ensuring its security • Critical-level vulnerabilities: Outline critical vulnerabilities found in the contract, such as a bug that allows attackers to steal currency • Medium-level vulnerabilities: Vulnerabilities that could damage the contract but with a limitation • Low-level vulnerabilities: Issues that don’t affect the contract • Inspecting the code line by line: Analysis of the lines of code with potential improvements

5. Disclaimer Smart contracts are deployed and executed on the Ethereum blockchain. An audit cannot explicitly guarantee that the smart contract will forever be secure, since changes on the Ethereum platform could create new attack vectors that affect the smart contract. This document is not meant to serve as a warranty about the safety or utility of the code contained in this smart contract and is designed for discussion purposes. Overview The project contains only one file, NftUpload.sol, composed of 114 lines of code written in Solidity. Relevant functions and state variables are commented on based on the natspec documentation.

6. What is a sandwich attack? • A sandwich attack is a front-running technique and common attack vector on decentralized exchanges running the automated market maker mechanism. • The goal of this attack is to manipulate the price of an asset as a result of buying and selling. • Sandwich attacks are possible because all blockchain transactions can be openly observed in the mempool • Once the attack bot notices a pending transaction of a victim exchanging asset X for asset Y, the victim is front-run by buying asset Y. Conclusion • Smart contract audits are especially necessary for DApps. A project having a smart contract isn’t an indication of value, but it is of great importance. • I encourage developers to continue learning and improving knowledge of latest updates when it comes to contract security and best practices