Security at different stages of Software Development Lifecycle

Security should be integrated into every stage of the Software Development Life Cycle (SDLC), not simply treated as an afterthought during testing or after deployment. Below is a stage-by-stage summary, highlighting main security practices and controls relevant to each phase.

Planning and Requirements

• Identify and document security requirements alongside functional requirements.
• Conduct initial risk assessments and determine applicable compliance standards.
• Define threat models and outline potential attack scenarios early.

Design

• Incorporate security in software and system architecture (secure design principles).
• Use threat modeling to anticipate and design against likely attack methods.
• Ensure architectural risk analyses and security reviews are held before implementation.

Implementation (Development)

• Apply secure coding standards and enforce them through code reviews.
• Use automated tools such as Static Application Security Testing (SAST) and Software Composition Analysis (SCA) for vulnerability detection.
• Prevent secrets from leaking into version control and establish good secret management practices.

Testing (Verification)

• Perform thorough code reviews, automated vulnerability scanning, and penetration testing.
• Use both manual and automated methods to verify the effectiveness of implemented security controls.
• Address common vulnerabilities such as injection flaws, broken authentication, and insecure dependencies.

Deployment

• Conduct final security assessments, including environment and configuration reviews.
• Enforce secure deployment practices (e.g., least-privilege, network segmentation, secure defaults).
• Ensure secrets, keys, and credentials are properly handled and stored.

Maintenance and Monitoring

• Continuously monitor for new vulnerabilities, apply regular patches and updates.
• Conduct periodic security assessments and incident response rehearsals.
• Monitor system logs for signs of compromise and adapt controls to emerging threats.

Summary Table

Security in the SDLC is most effective when applied proactively ("shift left"), involving all stakeholders throughout each stage rather than treating it as a single, isolated step toward the end.