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Control Institute
Category: Technical Security Controls

Secure Development Lifecycle

Also known as: SDLC, Secure Software Development Lifecycle, SSDLC, Security Development Lifecycle, SDL, Secure System Development Life Cycle, SSDLC (Secure System Development Life Cycle)
Simply put

A Secure Development Lifecycle is an approach to building software in which security is considered and built into every stage of development, rather than being added or checked only at the end. Instead of treating security as a final review step, it moves security practices, tools, and processes earlier into the design and build phases. The goal is to help teams produce more secure software by addressing risks throughout the entire development process.

Formal definition

A Secure Development Lifecycle integrates security practices, tools, and processes throughout every phase of the software (or system) development lifecycle, embedding "shift-left" security principles into activities that traditionally address only functional requirements. Depending on the framework used, the lifecycle may be structured into phases such as requirements, analysis, planning, design, development, documentation, testing, and deployment, with security considerations applied to each. Implementations vary: organizations may adopt vendor-defined practice sets (for example, Microsoft's Security Development Lifecycle) or standards-based approaches (such as a Secure System Development Life Cycle standard), and the specific phases, tools, and controls applied typically depend on the organization's scope and chosen framework. Within a compliance context, an SDLC is often relevant as an operational control demonstrating that security is managed across the development process, but the precise controls assessed depend on the applicable audit criteria or standard rather than the SDLC concept itself.

Why it matters

Software that reaches production with security defects can expose an organization to data loss, service disruption, and compliance failures that are difficult and costly to remediate after the fact. A Secure Development Lifecycle matters because it treats security as a continuous concern woven into requirements, design, development, testing, and deployment, rather than a final gate applied at the end of a project. Addressing risks earlier in the process typically makes them easier and less expensive to correct than discovering the same issues once code is already deployed.

In a compliance context, an SDLC is frequently the operational backbone that lets an organization demonstrate to auditors and certification bodies that security is managed across the way software is built. For a SOC 2 examination, evidence of secure development practices can support the controls evaluated under the applicable Trust Services Criteria, though the specific controls tested depend on the auditor and the defined scope. For an ISO/IEC 27001 ISMS, secure development activities may correspond to reference controls selected through the Statement of Applicability and informed by risk assessment. In both cases, the SDLC concept itself is not a control catalog; the precise controls assessed derive from the applicable criteria or standard.

It is important to keep expectations realistic. Adopting an SDLC does not guarantee that software will be free of vulnerabilities or that an organization will avoid a breach. Implementations vary widely depending on the framework chosen, the organization's scope, and the maturity of its engineering practices, and the value of an SDLC depends on how consistently the practices are actually applied.

Who it's relevant to

Security engineers and developers
Engineering teams are the primary practitioners of an SDLC, embedding security into requirements, design, development, and testing activities. Shifting security earlier helps them identify and address risks during the build rather than after deployment, though the specific tools and practices they use vary by the framework their organization adopts.
Compliance managers and GRC professionals
For those managing SOC 2 or ISO/IEC 27001 programs, an SDLC often serves as an operational control demonstrating that security is managed across the development process. The relevant evidence depends on the applicable Trust Services Criteria or, for ISO 27001, the reference controls selected through the Statement of Applicability, so GRC teams must map their SDLC practices to the criteria in scope.
Auditors and assessors
In a SOC 2 examination or ISO 27001 certification activity, assessors may review secure development practices as part of evaluating how an organization manages security across its software. The precise controls examined depend on the audit criteria, defined scope, and the auditor or certification body, rather than the SDLC concept itself.
Product and engineering leadership
Leaders responsible for delivery timelines and product quality benefit from an SDLC because addressing security risks throughout development is typically more efficient than remediating them after release. Leadership decisions on scope and framework selection shape how the lifecycle is structured and which practices are prioritized.

Inside SDLC

Requirements and Design Security
Security considerations introduced early in the lifecycle, including defining security requirements alongside functional ones and applying threat modeling during design to identify risks before code is written.
Secure Coding Practices
Development standards and guidelines intended to reduce common vulnerabilities, often supported by developer training and adherence to internal coding conventions.
Security Testing and Code Review
Verification activities such as peer code review, static and dynamic analysis, and vulnerability scanning performed to detect defects before release. The specific tools and depth typically vary depending on scope and organizational risk.
Change and Release Management
Controlled processes for approving, testing, and deploying changes, including segregation between development and production environments where applicable.
Post-Deployment Monitoring and Maintenance
Ongoing activities to identify and remediate vulnerabilities after release, including patching, dependency management, and responding to newly discovered issues.
Relevance to Compliance Frameworks
In a SOC 2 examination, SDLC controls are typically evaluated under the Common Criteria (Security) and, depending on scope, related change-management criteria; the CPA firm attests to their design (Type I) and operating effectiveness over a review period (Type II). Under ISO/IEC 27001, development-related activities are addressed within the ISMS requirements in clauses 4 through 10 and through applicable Annex A reference controls selected via the Statement of Applicability.

Common questions

Answers to the questions practitioners most commonly ask about SDLC.

Does implementing a Secure Development Lifecycle satisfy the requirements of both SOC 2 and ISO 27001 automatically?
No. A well-run SDLC can support control objectives under both frameworks, but it does not automatically satisfy either. Under SOC 2, an auditor evaluates how your development practices map to the applicable Trust Services Criteria (the Security Common Criteria at minimum, plus any optional categories in scope). Under ISO 27001, relevant Annex A reference controls would be selected through your Statement of Applicability and informed by risk assessment, while the certifiable requirements themselves sit in clauses 4 through 10. Because mapping between the two frameworks is only partial, demonstrating a mature SDLC to one does not automatically discharge the obligations of the other; the evidence, scope, and evaluation approach differ.
Is there a single mandatory set of SDLC controls I must implement to pass an audit or achieve certification?
Not universally. The specific SDLC controls that apply depend on your scope, risk assessment, the auditor or certification body, and the criteria selected. For SOC 2, controls are assessed against the Trust Services Criteria in scope rather than a fixed checklist. For ISO 27001, applicable Annex A reference controls are selected via the Statement of Applicability, so what is relevant varies by organization. Rather than treating any one approach as mandatory, most engagements focus on whether your controls are suitably designed and, for a SOC 2 Type II, operating effectively over the review period.
How should I document my SDLC to support a SOC 2 examination?
In most engagements, documentation should show both the design and, for a Type II report, the operating effectiveness of your development controls over the defined review period. This typically includes written policies and procedures, evidence of code review and approval, testing and vulnerability management records, and change management artifacts. The precise evidence expected depends on the applicable Trust Services Criteria in scope and the auditor's judgment. Bear in mind that a SOC 2 report attests only to the controls and period covered and does not guarantee freedom from breaches.
How does the SDLC relate to the Statement of Applicability in an ISO 27001 ISMS?
In an ISO 27001 context, the Annex A reference controls relevant to secure development are typically identified during risk assessment and then documented in the Statement of Applicability, which records which controls apply and the justification for inclusion or exclusion. Your SDLC procedures serve as the operational implementation of those selected controls. Because Annex A was restructured in the 2022 revision, the specific control references you cite should reflect the edition your ISMS is certified against. Remember that any resulting certificate covers only the defined scope of the ISMS.
What evidence of SDLC controls do auditors and certification bodies typically look for?
The evidence expected varies by scope, framework, and the assessing party, but it commonly includes documented development and change management processes, records of security testing and code review, vulnerability and patch management logs, and evidence of role-based access and approvals during development and deployment. For a SOC 2 Type II, evidence would generally need to demonstrate consistent operation across the review period, whereas a Type I focuses on suitability of design at a point in time. There is no single fixed evidence set; requirements depend on the criteria in scope and the auditor's or certification body's judgment.
How do we integrate SDLC controls into an existing DevOps or CI/CD pipeline for compliance purposes?
Many organizations embed security activities directly into their pipelines, such as automated testing, dependency scanning, and controlled approval gates, so that evidence is generated as part of normal operations. For SOC 2 purposes, this can help demonstrate that controls operate consistently over the review period; for ISO 27001, it can support the operational implementation of applicable Annex A reference controls selected through the Statement of Applicability. The right level of automation and control depends on your risk assessment and scope, so approaches vary between engagements rather than following a single mandated configuration.

Common misconceptions

Having a documented SDLC guarantees that software is free of vulnerabilities or breaches.
An SDLC reduces the likelihood of defects but does not guarantee freedom from vulnerabilities. A SOC 2 report attests only to the controls and period covered and does not guarantee freedom from breaches, and an ISO 27001 certificate covers only the defined scope of the ISMS.
Any single SDLC control, tool, or methodology is universally mandatory for SOC 2 or ISO 27001.
Specific SDLC controls, tools, and their depth typically depend on the auditor, certification body, scope, and applicable criteria. Frameworks generally expect appropriate secure development practices rather than prescribing one particular approach.
Satisfying SDLC requirements for one framework automatically satisfies the other.
Mapping between SOC 2 and ISO 27001 is possible but partial. SDLC evidence prepared for a SOC 2 examination may inform ISO 27001 work and vice versa, but meeting one framework's expectations does not automatically satisfy the other's.

Best practices

Integrate security requirements and threat modeling into the earliest requirements and design phases rather than treating security as a late-stage add-on.
Establish documented secure coding standards and provide developer training so practices are applied consistently across teams.
Incorporate layered verification, peer code review plus static and dynamic analysis, selecting tools and depth appropriate to the scope and risk of the application.
Maintain controlled change and release management, including separation between development and production environments where applicable, to produce reliable evidence for a SOC 2 examination or ISO 27001 assessment.
Continue post-deployment monitoring, patching, and dependency management to remediate newly discovered vulnerabilities throughout the software's life.
Retain evidence of SDLC activities in a form that supports both the design and operating-effectiveness testing typical of a SOC 2 Type II engagement and the ISMS documentation expectations of ISO 27001.