Secure Development Lifecycle (SDLC)

The Secure Development Lifecycle (SDLC) is a structured approach to software development in which security considerations, activities, and controls are integrated into every phase of the lifecycle, from initial requirements and design through implementation, testing, deployment, and maintenance.

What it includes

In industrial and manufacturing environments, a Secure Development Lifecycle commonly refers to how organizations build and maintain secure applications and systems such as MES, SCADA, data historians, quality systems, and integration middleware. Typical SDLC activities include:

• Requirements and planning: Defining security and regulatory requirements alongside functional requirements, such as user access needs, data classification, and logging expectations.
• Secure design: Applying security architecture patterns, threat modeling, and secure-by-design principles to system and interface designs, including OT/IT interfaces.
• Secure implementation: Using secure coding standards, code reviews, and dependency management for application, script, and configuration development.
• Verification and testing: Performing static and dynamic application security testing, vulnerability scanning, and security-focused system testing.
• Release and deployment: Applying change control, configuration baselining, environment hardening, and secure deployment procedures.
• Operations and maintenance: Monitoring for security events, applying patches, triaging vulnerabilities, and updating documentation and configurations.

The Secure Development Lifecycle can be applied to in-house custom development, configuration of commercial off-the-shelf systems, low-code workflows, and automation scripts that support production and quality operations.

How it is used operationally

Within manufacturing and regulated operations, SDLC practices often intersect with:

• Change management: Linking development tasks, test evidence, and approvals to formal change records.
• Configuration and document control: Governing versions of source code, scripts, configuration files, and related specifications.
• Cybersecurity programs: Aligning with broader OT and IT security policies, such as network segmentation, identity and access management, and incident response procedures.
• Compliance and audits: Providing traceable documentation of how security requirements were considered, implemented, and verified throughout development.

What it is not

• It is not a single tool or software product. It is a process or framework that may use many tools.
• It is not limited to one development methodology. It can be applied to waterfall, agile, DevOps, or hybrid approaches.
• It is not the same as general software development lifecycle without security; the key distinction is the systematic integration of security activities.

Common confusion

• SDLC (Secure Development Lifecycle) vs. SDLC (Software Development Life Cycle): “SDLC” often refers to the generic software development life cycle. In security and compliance contexts, the same acronym is commonly expanded to Secure Development Lifecycle to emphasize security-specific practices added to the standard development process.
• Secure Development Lifecycle vs. vulnerability management: Vulnerability management focuses on finding and remediating vulnerabilities in deployed systems. A Secure Development Lifecycle focuses on preventing and detecting security issues throughout development, though it should work in coordination with vulnerability management processes.