SECURE CODE REVIEW · OWASP TOP 10 · DEVSECOPS · PCI DSS REQ. 6

Secure Code Review
Stop Shipping Vulnerabilities

ThreeShield performs manual and automated secure code reviews for web applications, APIs, and infrastructure code. We discovered CVE-2023-27739 during a routine client code review. Our reviews find what SAST tools miss — logic flaws, authentication bypasses, and business-layer vulnerabilities that automated scanners don't understand.

CVEThreeShield discovered CVE-2023-27739 (EasyXDM XSS & arbitrary redirection) during a routine client code review
15+Languages supported including Python, PHP, JavaScript, Go, Java, C#, TypeScript, Rust, and more
OWASPReviews cover the OWASP Top 10 and OWASP Application Security Verification Standard (ASVS)
PCI Req. 6PCI DSS Requirement 6 mandates secure development practices and code review for cardholder data applications

Why Manual Code Review Finds What Automated Tools Miss

SAST and DAST tools are excellent at finding known vulnerability patterns. They are poor at understanding business logic, authentication flows, and the context-specific flaws that make the difference between a theoretical issue and an exploitable breach.

What SAST/DAST tools find well

  • Known injection patterns (SQL, command, XSS)
  • Hardcoded credentials and API keys in source
  • Use of known vulnerable library versions
  • Missing security headers in web responses
  • Common misconfigurations in framework defaults

What ThreeShield's review adds

  • Business logic flaws (as in CVE-2023-27739 — the library behaved as designed but was exploitable)
  • Authentication and authorization bypass paths
  • Race conditions and time-of-check/time-of-use (TOCTOU) issues
  • Insecure third-party library integration patterns
  • Trust boundary violations between components
  • Cryptographic implementation errors (not just algorithm choice)

Languages & Frameworks Supported

Web & APIsPHP · JavaScript · TypeScript · Node.js · React · Python · Go (Golang) · Java · C# / .NET
Infrastructure & ScriptsBash · PowerShell · Batch · Python automation · Terraform · Docker & Kubernetes configs
DatabaseMySQL · PostgreSQL · SQL Server · stored procedures · query parameterization review
MobileFlutter/Dart · React Native · Swift · Kotlin — secure storage, certificate pinning, authentication
SystemsC · C++ · Rust · Visual Basic · VB.net — memory safety, buffer handling, unsafe code blocks
FrameworksLaravel · Django · Rails · Spring · Express · ASP.NET — framework-specific misconfigurations and CSRF protections

Compliance-Driven Code Review

PCI DSS Requirement 6 — Secure Development

PCI DSS v4.0.1 Requirement 6 mandates secure development practices, security training for developers, and code review for custom application code in the cardholder data environment. ThreeShield's code reviews satisfy the Requirement 6.3.2 code review obligation with documentation suitable for QSA review.

OWASP Top 10 & ASVS

Reviews are structured against the OWASP Top 10 (Injection, Broken Auth, XSS, IDOR, Security Misconfiguration, Vulnerable Components, Logging Failures, SSRF, and others) and where appropriate, the Application Security Verification Standard (ASVS) for more comprehensive verification requirements.

Privacy Compliance — PIPEDA / HIA / GDPR

Applications handling personal or health information need to implement privacy-by-design principles in code — not just in policy documents. ThreeShield's reviews assess data minimization, storage encryption, access logging, and consent mechanisms in code, mapping findings to your applicable privacy framework.

Bug Bounty Program Support

For organizations running bug bounty programs, ThreeShield can review incoming submissions, triage severity, and manage the response process. We can also help scope and structure your bug bounty program to encourage high-quality submissions while limiting the scope to what you can actually remediate. Note: third-party services and code are excluded from ThreeShield's own bug bounty program.

DevSecOps Integration

One-time reviews find point-in-time issues. Sustainable security requires integrating security review into the development pipeline so problems are caught before they ship.

1

Pre-Commit Hooks & Developer Guidelines

ThreeShield configures pre-commit security checks and provides developer-facing secure coding guidelines specific to your stack and business context. The goal is shifting security left — catching issues when they are cheapest to fix, not during a penetration test that delays your release.

2

Pipeline Integration (CI/CD)

We integrate appropriate SAST/DAST tools into your CI/CD pipeline — GitHub Actions, GitLab CI, Jenkins, Azure DevOps, or whatever you use — and configure them to surface results without flooding developers with noise. ThreeShield reviews SAST/DAST output and provides context on which findings are genuine versus false positives.

3

Change Review

ThreeShield can participate in code review for significant changes — particularly changes to authentication, authorization, data handling, payment flows, and API endpoints. This is the "axe-sharpening" model: a small investment in review prevents much more expensive remediation during a penetration test or after a breach.

4

Developer Training

Security review findings are most useful when they teach developers to avoid the same issue in future code. ThreeShield provides developer-facing training on the specific vulnerability classes relevant to your stack — not generic OWASP slide decks, but concrete examples from code that looks like yours.

Frequently Asked Questions

A penetration test looks at your application from the outside — it finds vulnerabilities that are externally exploitable. A code review looks at the source code directly and can find vulnerabilities that aren't externally reachable yet, logic flaws that a scanner can't detect, and security debt in code that isn't deployed. Ideally you do both: code review before release, penetration test after. Many compliance frameworks (PCI DSS Req. 6, for example) specifically require code review in addition to penetration testing.

ThreeShield can work with full repository access, targeted file access, or code snippets depending on your comfort level. Targeted access focused on authentication, authorization, data handling, and third-party integrations typically yields the highest-value findings in the least time. Full access enables a comprehensive review including dependency analysis and configuration review.

Code shared with ThreeShield is handled under NDA and subject to the same security controls we apply to all client data — encrypted storage, access controls, and retention limits. We never copy, store, or retain source code beyond the scope of the engagement. Secure code transfer options include direct repository access with revocable credentials, or encrypted file transfer. We do not retain copies after engagement completion.

Yes — for custom code, plugins, themes, and configurations built on top of third-party platforms. We focus on the code and configuration you control. Third-party core code (Shopify core, Salesforce platform, WordPress core) is not in scope for a standard code review, but we assess how your custom code interacts with those platforms and whether you're using them in ways that introduce risk.

Stop Shipping Security Debt

ThreeShield's secure code reviews find what automated tools miss — before penetration tests or real attackers do. Our discovery of CVE-2023-27739 during a routine client review is exactly the kind of result that protects your clients and your reputation.

Request a Code Review Book a Call →

Also see: CVE-2023-27739 — discovered by ThreeShield during client code review