Secure Code Review: What It Checks and Best Practices

Secure code review “is the process of manually examining source code to identify security vulnerabilities that automated tools often miss,” according to the OWASP Secure Code Review Cheat Sheet. You’ll also see it called a source code review or security code review.

OWASP stresses that “the core analysis relies on human judgment and domain expertise.” From a Pentestica review, you get an Executive Summary for leadership and a Technical Report for developers, listing each vulnerability with evidence and step-by-step remediation.

Core focus areas

• Input validation and sanitization: Reviewers follow untrusted data from where it enters, such as forms, API parameters, files and headers, to where it’s used in queries, templates or system commands. Validation has to happen on the server.
• Authentication and authorization: Reviewers check login, session handling and password reset. Then the harder question: does every function confirm that this user may access this record? The same question drives web application penetration testing and API penetration testing.
• Secrets and credential management: OWASP’s checklist asks for “No hardcoded secrets, proper secret storage and rotation.” In mobile app tests, we’ve found an API key inside the app package. It didn’t give direct full access to the infrastructure, but it allowed operations that the backend should have controlled. A scan of the device doesn’t always judge what a specific secret means in the context of the whole architecture. The client moved the operation to the backend and revoked the key.
• Cryptographic implementation: Reviewers check which algorithms and modes are used, how keys are generated and stored, and whether random values come from a secure source.
• Error handling and logging: Error messages shouldn’t reveal stack traces, queries or internal paths. Logs should record security events without storing passwords or tokens.

Manual review vs. automated tools

You need both. OWASP puts it this way: “Manual Code Review complements automated security testing tools (SAST/DAST).”

• Automated scanners (SAST, SCA, IaC): SAST checks your own code for known risky patterns, SCA flags third-party dependencies with known vulnerabilities, and IaC scanning checks infrastructure templates for misconfigurations. They’re fast, but they don’t know your business rules, and their output needs triage. Our guide to automated penetration testing explains where automation stops.
• Manual code review: A reviewer reads the code with the application’s purpose in mind. That’s how business logic flaws and missing authorization checks surface: code that looks clean but lets the wrong user do the wrong thing.

Best practices

• Shift left: Check security while code is being written, not after release. A flaw caught early is fixed by the developer who wrote it, while the context is still fresh.
• Pull request checklists: OWASP describes “Security-focused review of code changes as part of standard PR process.” For APIs, our API penetration testing checklist gives you a starting list.
• Combine approaches: Use scanners and checklists on every change, then bring in an external manual review for high-risk code such as authentication and payments. White box penetration testing goes further, pairing code access with attacks on the running system.

When to order a secure code review, and what it costs

Order an external review before a major release, after a significant rewrite, when code handles authentication, payments or sensitive data, or when a customer or auditor asks for independent evidence. If no one in-house owns secure development and testing decisions, a virtual CISO (vCISO) can set that schedule.

Before the review, prepare:

• Repository access for the code in scope
• An architecture diagram and the main data flows
• Your priority modules or services

A secure code review is quoted individually, in tester-days after a scoping call. If you pair it with a penetration test, a standard web application or API test on its own costs $2,500 to $5,500 and typically takes 5 to 10 tester-days. The price is fixed for the agreed scope and confirmed in writing before work starts, and a retest is available after fixes. We manually verify 100% of reported findings. See our penetration testing pricing.

Sources: OWASP Secure Code Review Cheat Sheet.