SDLC Security

What is SDLC security?

SDLC security refers to practices that embed security across the software development lifecycle. Instead of treating security as a final step before release, it is applied at every stage, from design and coding to testing, deployment, and maintenance.

The goal is to build applications that are secure by design, not just patched after vulnerabilities are discovered. This requires structured processes such as secure coding standards, automated testing, and architecture reviews that align with the broader application security lifecycle.

In practice, SDLC security reduces risk exposure, improves compliance readiness, and saves time by preventing costly fixes in production. Related concepts such as secure software development provide additional context, showing how development security extends beyond code to include governance, infrastructure, and monitoring.

Core principles of software security in the development lifecycle

Embedding security across the SDLC requires clear principles that guide both developers and security teams. These principles establish a foundation for building secure software without creating friction in delivery:

• Shift security left: Security should begin during requirements and design, not after testing. Practices like secure design reviews and threat modeling help identify risks before they reach production.
• Automate wherever possible: Automated testing, such as static application security testing (SAST), software composition analysis, and secret scanning, ensures coverage across large codebases while reducing manual overhead.
• Secure coding practices: Standards for input validation, authentication, encryption, and error handling form the baseline of development security. These practices prevent common vulnerabilities, like injection flaws and broken access control.
• Continuous validation: Security isn’t a one-time step. Integrating checks into CI/CD pipelines and runtime monitoring ensures ongoing coverage throughout the software security development lifecycle.
• Context-driven prioritization: Not every vulnerability has the same impact. Risks should be prioritized based on exploitability, business impact, and where the issue appears in the application security lifecycle.
  

When consistently applied, these principles make SDLC security an operational reality rather than an abstract goal. They help organizations reduce costly rework, accelerate compliance, and give developers confidence that their applications are secure by design.

Challenges in implementing SDLC security

While the value of SDLC security is clear, putting it into practice can be difficult. Many organizations struggle to balance security with speed, and several recurring challenges stand out:

• Tool fragmentation: Development teams often use multiple disconnected scanners—SAST, DAST, SCA—that produce overlapping or conflicting results. Without a unified view, it becomes hard to measure progress across the entire software security lifecycle.
• Developer adoption: Security practices that disrupt workflows face resistance. Unless controls integrate into IDEs, CI/CD pipelines, and code review processes, developers may bypass them to maintain velocity.
• Evolving attack surfaces: New architectures like microservices, APIs, and AI-driven frameworks expand the range of risks. SDLC security must adapt continuously to keep pace with changing technology stacks.
• Compliance alignment: Teams need to prove adherence to frameworks such as PCI DSS, NIST SSDF, and ISO 27001. Mapping these requirements into daily development security activities can be complex and time-consuming.
• Architecture drift: As systems evolve, initial security controls often decay. Monitoring for drift helps ensure that the protections designed into an application remain intact
  

Overcoming these challenges requires not only the right tools but also a cultural commitment. By aligning security practices with developer workflows and continuously validating controls, organizations can embed resilience throughout the software security development lifecycle.

Related Content: Detect architecture drift early in the SDLC

Integrating OWASP controls into your SDLC

The OWASP Top 10 and related frameworks are widely recognized as baselines for secure software development. To make them effective, they should be integrated into the SDLC at every stage rather than treated as a one-time checklist.

Design stage: applying threat modeling

At the design stage, teams can use threat modeling to map out authentication flows, data access patterns, and external integrations. Identifying risks such as insecure APIs or weak authorization early makes it easier to build defenses into the architecture. These design-time checks align directly with the principle of “security by design.”

Coding stage: enforcing secure development practices

During coding, security policies should be embedded into developer workflows. This includes enforcing secure input validation, consistent error handling, and strong encryption standards. Integrating these controls into IDEs or pull request checks helps developers adopt them without slowing down productivity, making development security a natural part of the process.

Testing stage: automating vulnerability detection

Testing is where security controls can be validated at scale. Automated approaches such as SAST, SCA, and dynamic testing uncover weaknesses introduced in earlier phases. Linking these results back to business context in the application security lifecycle helps distinguish critical risks from lower-priority findings, reducing noise and focusing remediation efforts.

Deployment and runtime stage: monitoring and feedback loops

Security does not stop at release. During deployment and runtime, monitoring for misconfigurations, exposed APIs, and privilege escalation attempts ensures defenses remain active. Importantly, runtime findings should be mapped back to code owners, creating a feedback loop that strengthens future development cycles.

Continuous improvement through integrated controls

The most effective programs treat OWASP guidance as part of a living process. Integrating OWASP controls into agile workflows allows organizations to release quickly while continuously addressing risks. This ensures that security grows in step with software complexity.

Related Content: SDLC and DevSecOps: Moving to a continuous and simultaneous model

Mapping security controls to each SDLC phase

A secure SDLC requires clear alignment between each development stage and its corresponding security activities:

• Requirements: Define security objectives and compliance needs.
• Design: Perform threat modeling and establish secure design patterns.
• Implementation: Enforce secure coding standards and use automated code analysis.
• Testing: Apply SAST, DAST, and penetration testing.
• Deployment: Validate configurations, access controls, and infrastructure-as-code.
• Maintenance: Monitor runtime behavior, patch vulnerabilities, and review incidents.

This mapping ensures security is not a bolt-on but an embedded part of the lifecycle.

Frequently asked questions

How does SDLC security reduce cost and risk compared to post-release fixes?

By addressing vulnerabilities during design and development, fixes are applied before they become exploitable. This avoids the significantly higher costs and risks of patching software after it has been released to production.

Which SDLC phase is most critical for embedding security controls?

All phases contribute, but the design and coding stages are the most impactful. Security decisions made early influence the entire lifecycle and prevent flaws from cascading into later stages.

Are there industry frameworks recommended for secure SDLC implementation?

Yes. Frameworks such as NIST SSDF, OWASP SAMM, and ISO/IEC 27034 provide structured approaches for embedding security controls into the software development lifecycle. They help align practices with compliance and industry standards.

Can development teams maintain pace while enforcing SDLC security measures?

Yes. When controls are automated and integrated into CI/CD pipelines, developers receive fast feedback on risky changes. This allows teams to maintain delivery speed while strengthening the software security lifecycle.

How does secure coding enforce security across the SDLC?

Secure coding standards ensure that developers consistently apply best practices for input validation, error handling, authentication, and encryption. These practices reduce the likelihood of introducing vulnerabilities at every phase of the SDLC.