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Secure Code Review

Picture of Gabriela Silk   Gabriela Silk  ·  6 minute read

Modern software systems function in the heart of almost all business. Everything from financial services and healthcare platforms to critical infrastructure and cloud-native applications all run on modern software systems. In the era of Agile and DevOps practices, developers write and deploy code quicker than ever to speed up development. Unfortunately, speed without security brings security risks. Vulnerabilities created during development also tend to propagate into production and can lead to very costly, dangerous, and occasionally catastrophic data breaches.

Data breaches, ransomware incidents, and supply-chain attacks frequently trace back to insecure code rather than failures in firewalls or perimeter defenses. Attackers increasingly exploit logic flaws, improper input validation, broken authentication mechanisms, and insecure dependencies embedded directly in applications. To avoid pushing insecure codes into production environments, organizations must adopt proactive practices that identify weaknesses before release rather than reacting after compromise.

 

Contents

 

What is Secure Code Review?

Secure Code Review is a structured analysis of an application’s source code to identify security vulnerabilities, insecure coding practices, and design weaknesses before deployment. It combines elements of software engineering, cybersecurity, and auditing to evaluate whether code adheres to secure development standards. Unlike traditional code reviews that focus primarily on readability, performance, or maintainability, secure code reviews concentrate specifically on security risks such as:

  • Injection vulnerabilities such as SQL, OS command, and LDAP injection  

  • Authentication and authorization flaws

  • Improper session management

  • Insecure cryptographic usage (hardcoded keys, weak algorithms (MD5, SHA1), improper key management 

  • Data exposure

  • Memory safety issues
  • Misconfigurations
  • Business logic vulnerabilities 

The goal is not simply to find bugs, but to assess whether the application’s implementation supports confidentiality, integrity, and availability (CIA). Reviewers analyze how data flows through the system, how trust boundaries are enforced, and how input validation is handled.

Secure code reviews may be conducted manually by experienced security engineers, automatically using static analysis tools, or through a hybrid approach that blends both techniques for maximum effectiveness.

 

The History of Secure Code Review

Code review has been part of software engineering best practices for quite some time. Early peer reviews were less about security and more about quality and maintainability. As systems became increasingly interconnected and internet-facing in the late 1990s and early 2000s, vulnerabilities had far more impact. High-profile breaches revealed systemic flaws in software development methods. Many security problems arose from coding and not infrastructure misconfigurations as organizations were realizing. Secure development methods then became established in the industry. Frameworks such as: 

  • OWASP Secure Coding Practices

  • Microsoft SDL (Security Development Lifecycle)

  • NIST Secure Software Development Framework (SSDF)

The adoption of secure software development  CI/CD pushed the implementation of all these security checks earlier on in the development process. Tools for Static Application Security Testing (SAST) have matured to perform automated code scans. Similarly, the DevSecOps movement promoted “shift-left security,” which was about integrating security checks straight into the code development pipeline, with reviews not as an afterthought to catch bugs later in the way. Secure code review is foundational to application security programs now, and is commonly required by compliance frameworks, regulatory standards, and enterprise governance models.

 

Why is Secure Code Review Important?


1. Early Detection Reduces Cost

Post-production fixing of vulnerabilities can be extremely costly compared to fixing them while they are still in development. If a software vulnerability is found post-release, it may need patches, incident response, customer notifications, and brand reputation control. Secure code review detects issues early where remediation is simple.

2. Prevents Exploitable Vulnerabilities

The biggest vulnerabilities are bugs in code, not complex exploits. Often common issues such as missing input validation and unsafe deserialization can be directly found in source code.

3. Strengthens Compliance and Governance

Many of these standards such as PCI DSS, HIPAA, ISO 27001, and SOC 2 require secure coding practices to be implemented in all organizations. Documented examples like code review offer evidence that security controls are actively enforced.

4. Improves Software Quality

Robust coding is also often a complement to secure coding. Clear validation, structured logic, and defensive programming reduce both security risks and operational faults. 

5. Enhances Security Culture

Regular reviews nurture developer awareness. As time goes by, teams gradually learn these secure patterns and have fewer security vulnerabilities in their code. 

6. Supports Risk-Based Security

Organizations can prioritize high-risk components such as authentication modules, payment systems, and data processing engines. In short, secure code review transforms security from reactive patching into proactive prevention.

 

The Secure Code Review Process

Secure code review follows a structured methodology. Since Ad hoc scanning rarely produces consistent results, repeatable workflows are used in mature organizations.

 

Defining Review Objectives

Before review can start, teams must determine:

  • Scope (specific modules, features, or entire repositories)

  • Risk profile

  • Compliance requirements

  • Security standards and policies

  • Expected deliverables

High-risk applications need more thorough manual inspection while lower-risk systems may rely more on automation. Defining goals helps to manage resources effectively.

 

Review Execution

Execution typically includes:

1. Understanding the architecture

Reviewers analyze system design, trust boundaries, data flows, and integrations.

2. Threat modeling

Identify potential attack vectors and prioritize sensitive components.

3. Secure code inspection

Evaluate code against security patterns and anti-patterns.

4. Static analysis tools

Automated scanners detect known vulnerability classes.

5. Dependency analysis

Third-party libraries are checked for known CVEs.

6. Manual verification

Validate flagged issues and search for logic flaws that automation misses.

Execution requires deep technical expertise and contextual understanding of how the application operates.

 

Reporting and Documentation

Findings must be documented clearly:

  • Vulnerability description

  • Risk rating (CVSS or organization-defined risk scoring models)

  • Impact assessment

  • Reproduction steps

  • Remediation guidance

  • Code references

Well-structured reports help developers quickly understand and fix issues.

 

Remediation and Follow-up

A review is incomplete without remediation:

  • Developers patch vulnerabilities

  • Security validates fixes

  • Lessons are incorporated into standards

  • Metrics are tracked for improvement

Continuous feedback ensures lasting security gains rather than one-time assessments.

 

Manual vs Automated Code Review

Both approaches have strengths and limitations.

Manual Review

Advantages:

  • Detects business logic flaws

  • Understands context

  • Reduces false positives

  • Identifies architectural weaknesses

Limitations:

  • Time-intensive

  • Requires specialized expertise

  • Hard to scale across large codebases

Automated Review

Advantages:

  • Fast and scalable

  • Consistent

  • Integrates into CI/CD pipelines

  • Catches common vulnerability classes

Limitations:

  • False positives/negatives

  • Limited contextual awareness

  • Cannot detect complex logic issues

Hybrid Approach

Most organizations combine both methods:

  • Automated scans for broad coverage

  • Manual review for critical components

This balance delivers depth without sacrificing speed.

 

Best Practices for Secure Code Review

Creating a Secure Coding Policy

A formal policy establishes expectations:

  • Approved frameworks

  • Input validation standards

  • Encryption requirements

  • Authentication practices

  • Dependency management rules

Policies provide a baseline against which reviews are conducted.

Training and Awareness for Secure Coding

Developers are the first line of defense. Training should include:

  • OWASP Top 10 risks

  • Language-specific vulnerabilities

  • Secure design principles

  • Case studies of real breaches

Educated developers introduce fewer issues, reducing review overhead.

Continuous Integration an Continuous Deployment (CI/CD) Security

Security must be embedded in pipelines:

  • Automated SAST scanning

  • Dependency vulnerability checks

  • Secrets detection

  • Policy enforcement gates

This ensures vulnerabilities are detected before merging or release.

Note - While SAST is an automated analysis tool, secure code review is the broader process that may include SAST and manual inspection. To further clarify, secure code review often integrates into DevSecOps pipelines, but remains a distinct security control focused specifically on source code analysis.  

Regular Review and Updating of Practices

Threat landscapes evolve. Organizations should:

  • Update tools and signatures

  • Revise policies

  • Review metrics

  • Conduct periodic audits

Continuous improvement keeps defenses relevant.

 

Balancing Delivery Speed with Security

Development teams are frequently stressed due to the need to build features quickly, which can lead to friction with thorough security analysis. A risk-based approach works to mediate the various priorities, thus balancing these conflicting priorities. Automated tools offer broad, scalable coverage for common vulnerability classes, while manual reviews tend to concentrate on critical or sensitive components that require deeper expertise.

Organizations ensure speed through delivery cycles without sacrificing security assurance by using the risk to determine how much effort is worth and then automating mundane tasks. That balance allows for agility and protection.

 

Expanding the Tool Ecosystem Beyond SAST

While static analysis tools are critical to secure code review, they are only a piece of a vast ecosystem. Additional technologies enhance coverage and address risks that SAST alone may miss, such as Software Composition Analysis tools that evaluate open-source dependencies for known vulnerabilities, secret scanners that detect hardcoded credentials, and review orchestration platforms that consolidate findings across repositories.

Several complementary tools help organizations understand the risk better and manage both proprietary code and third-party code exposure.

 

Metrics, Collaboration, and Continuous Improvement

Secure code review should be an ongoing program and not a one-time assessment. Measuring performance by defined metrics allows an organization to gain an idea of effectiveness and identify trends across the company. Useful indicators are vulnerabilities per release; average time to remediation; recurring defect types and false positive rates.

Sharing results among teams facilitates knowledge transfer between developers and security professionals. Over time, these feedback loops reinforce secure coding habits, reduce repeat issues, and improve the overall maturity of the organization’s security posture.

 

Secure Code Review vs. Penetration Testing

Where penetration testing evaluates a running application from an attacker's perspective, code review focuses directly on the source code and implementation logic.

Additional Considerations

Metrics and KPIs

Track:

  • Vulnerabilities per release

  • Time to remediation

  • False positive rates

  • Security debt

Metrics inform program effectiveness.

Third-Party Code and Supply Chain Risks

Modern applications rely heavily on open-source components. Reviewing dependency health is essential to prevent inherited vulnerabilities.

Risk-Based Prioritization

Not all findings are equal. Focus first on issues that affect sensitive data or critical systems.

 

Conclusion

As applications become more complex and attack surfaces expand, organizations must embed security directly into development processes. Reviewing code systematically enables teams to detect vulnerabilities early, reduce risk exposure, and build resilient systems.

At Prescient Security we combine structured processes, skilled manual inspection, automated tooling, and strong governance practices to help organizations proactively identify exploitable flaws before they reach production.  Beyond compliance and risk reduction, secure code review strengthens engineering discipline and fosters a culture of accountability.

Ultimately, secure software is not the result of a single tool or audit. It is the product of consistent practices applied throughout the lifecycle. Secure Code Review remains one of the most powerful mechanisms to achieve that goal ensuring that the foundation of every application, its code, is built with security at its core.

 

Learn more about Security Code Review from one of our experts and how you can leverage it for your organization.