Smart Contract Audit Checklist: What Auditors Check

Smart Contracts

2025-05-25

Smart Contract Audit Checklist: What Auditors Check

Access control flaws caused $953M in 2024 losses. Learn exactly what auditors check before deployment and how to pass your security review first time.

Frequently Asked Questions

A standard audit takes one to four weeks depending on contract complexity and line count. Simple ERC-20 tokens can be reviewed in three to five business days. Multi-contract DeFi protocols with upgradeable proxies and governance modules typically require three to six weeks for thorough manual plus automated review.

Audit costs range widely based on contract complexity. Simple single-contract projects can be reviewed for a few thousand dollars. Mid-complexity DeFi protocols typically require significantly more investment including the initial audit and remediation review. Given that access control failures alone caused nine-figure losses in 2024, the ROI calculation is straightforward.

No. Automated tools cover the majority of known pattern-based vulnerabilities but consistently miss business logic flaws, complex reentrancy paths, economic attack vectors, and protocol-level invariant violations. Manual auditors catch the vulnerability fraction that causes the largest losses.

Fix all critical and high-severity findings before deployment. Run a remediation review with the original auditor. Deploy behind a time-locked proxy. Set up a bug bounty program. Monitor deployed contracts with on-chain tooling like Forta or OpenZeppelin Defender.

Established firms include Trail of Bits, OpenZeppelin, Halborn, Sherlock, ConsenSys Diligence, and Code4rena. For protocol selection, check their public portfolio and review post-mortems for any projects they audited that were later exploited.