Secure Software Development Lifecycle

Understand why an SSDLC is important, examples of format SSDLC processes such as NIST SSDF and OWASP CLASP, and learn to embed security into all stages of the SDLC.

December 13, 2021

What is a Secure SDLC?

The software development life cycle (SDLC) framework maps the entire development process. It includes all stages—planning, design, build, release, maintenance, and updates, as well as the replacement and retirement of the application when the need arises.

The secure SDLC (SSDLC) builds on this process by incorporating security in all stages of the lifecycle. Teams often implement an SSDLC when transitioning to DevSecOps. The process involves applying security best practices alongside functional aspects of development, and securing the development environment.

In this article:

The Importance of a Secure SDLC

It is a common belief that security requirements and testing inhibit the development process. However, a secure SDLC provides an effective method for breaking down security into stages during the development process. It unites stakeholders from development and security teams with a shared investment in the project, which helps to ensure that the software application is protected without being delayed. 

Developers may start by learning about the best secure coding frameworks and practices. They should also look into using automated tools to identify security risks within the code they write and to detect security vulnerabilities in the open source libraries they bring into their projects.

In addition, the management team may use a secure SDLC as a vehicle to implement a strategic methodology to create a secure product. For example, managers can perform a gap analysis to gain insight into which security activities or policies currently exist, which are absent, and to see how effective they are at each stage of the SDLC.

To achieve a streamlined SSDLC and ensure software shipping deadlines are not missed, it is necessary to establish and enforce security policies that help address high-level issues like compliance without requiring manual review or manual intervention. To achieve this, some organizations choose to hire security experts to evaluate security requirements and to create a plan that will help the organization improve its security preparedness. 

Related content: Read our guide to application security

Examples of a Secure SDLC

Here are some examples of popular frameworks used to establish secure software development lifecycles:

NIST Secure Software Development Framework (SSDF) 

The secure software development framework (SSDF) was created by the National Institute of Standards and Technology (NIST), the same organization tasked with maintenance of the National Vulnerability Database (NVD) tracking publicly known software vulnerabilities. 

The SSDF defines software development practices that can help realize a secure SDLC. The framework includes documents that outline and prescribe standards, guidelines, and software development practices. Notable practices include:

  • Providing secure coding training to edevelopers, to ensure security from the start
  • Automating and integrating security tests to detect security risks as close to the point of remediation as possible
  • Securing open source components and libraries present within projects

The goal of NIST’s secure software development framework is to help reduce the number of vulnerabilities in software released to production environments, as well as to mitigate the impact of potential exploitation of unaddressed and undetected vulnerabilities. The framework can also help address root causes and prevent future recurrences of vulnerabilities.

MS Security Development Lifecycle (MS SDL)

MS SDL was proposed by Microsoft for the purpose of supporting the modern development pipeline with dependable security considerations. The SDL includes a collection of practices chosen especially to help support compliance requirements and security assurance. Developers can use the SDL to reduce the amount and severity of vulnerabilities within their codebase while also reducing development costs and setbacks due to late-stage remediation. 

OWASP Comprehensive, Lightweight Application Security Process (CLASP)

CLASP is built of rule-based components that implement security best practices. It can help developers secure applications at early phases of the development cycle and implement security in a structured and repeatable way.

CLASP was developed by analyzing actual development teams in the field, deconstructing their development lifecycles, and identifying the most effective way to add security practices to their established workflows. CLASP not only addresses ways to enhance established processes, but also helps teams address specific vulnerabilities and coding weaknesses which could be exploited and lead to major security breaches.

Embedding Security into All Phases of the SDLC

Ideally, you should secure each phase of the SDLC in the most appropriate manner for stakeholders present at that stage, while also ensuring that each security measure facilitates security practices across the whole project. Here are some key security practices to consider:


During the planning phase, stakeholders consider key aspects of the project and their alignment to the strategy for the final product. Examples of the topics considered at this phase include resource allocation, project scheduling, capacity planning, and provisioning. 

At the end of this phase, you should have several outputs in hand, including cost estimations, procurement requirements, task schedules, and project plans. In a secure SDLC, considerations should be made for security, accounting for any additional requirements which could influence these deliverables. To ensure all perspectives are represented in the outputs of this phase, development teams and project managers should collaborate with stakeholders in security and operations.

Requirements and Analysis

This phase involves deciding which frameworks, languages, and technologies should be used. It is important to determine which vulnerabilities or insecure coding practices may be particularly relevant to the selected resources. 

For example, certain frameworks may lack security competencies for your specific environment, or some technologies may be incompatible with security tools already in use elsewhere in your organizations. Failure to consider the full breadth of implications here can potentially threaten the security of all technologies chosen during this phase and those which are incorporated at later stages. 

Design and Prototyping

The design phase involves using established patterns of application architecture and software development. For example, software architects may decide to leverage an architecture framework that enables the use of existing components and promotes standardization.

Proven design patterns help developers solve algorithmic problems in a consistent manner. Additionally, this phase may include rapid prototyping (or spike), which helps compare technologies and find the most suitable solution to achieve the requirements identified in the earlier phase. 

The output of the design and prototyping phase includes:

  • Design documents—include a list of all components and patterns chosen for the project.
  • Code—produced by spikes and used as a starting point for further development.

In a secure SDLC, beginning the design and prototype phase with security in mind will help to minimize disruption to workflows later, which may otherwise result from security policy noncompliance or failed application security testing.

Development and Testing

It is critical to include secure coding standards during the development phase, as well as encouraging selection of secure open source and third-party components being brought into the project. This typically includes a code review process that helps ensure the project has met the required features and functions, as well as various testing that identifies weaknesses in custom code, known open source vulnerabilities. 

If your organization relies on DevSecOps methodologies, this testing can occur directly within the tools developers are using, accelerating risk detection and shortening time to remediation. More traditional workflows will follow the development phase with application security testing, the results of which are sent back to development teams to be addressed via issue management workflows.


In keeping with DevOps and cloud native software methodologies, the deployment phase should be automated as much as possible. High-maturity enterprises often implement this phase in a manner that deploys software as soon as it is ready, at the end of a dedicated sprint or development cycle. This approach should not be employed, however, unless security tools and practices can accommodate this velocity and block potential security risks from being deployed into production environments. 

Enterprises with lower DevOps maturity, or those operating within highly regulated industries, may require manual review and approval prior to deployment, particularly for business-critical applications or those handling sensitive data. 


Even after performing extremely thorough testing processes, newly published vulnerabilities may impact applications that have been pushed into production. Additionally, an application may behave differently at runtime in production environments than it does in a static state or in development environments. This is why security efforts should not stop once your application is released. Security is a continuous cycle that should be maintained on a regular basis. 

Your maintenance phase begins immediately after the deployment phase, and should ensure a path of direct feedback and communication between security and development teams. Preparations should be made for accelerated issue management and risk remediation to reduce the window of opportunity for an attack on production assets. 

Operations or DevOps teams should also ensure proper security configuration of cloud environments and resources associated with application functionality, such as container engines and orchestration tools. Regularly perform these security checks against the software and the environments, update them regularly to meet evolving requirements, and ensure compatibility with any new tools being used elsewhere in the secure SDLC. 

Related content: Read our guide to shift left DevOps

Implementing a Secure SDLC with Aqua Security

Aqua’s cloud native security platform is purpose-built to engender security throughout all stages of a secure SDLC and into production deployments across cloud environments. Aqua enables security and DevOps teams to detect security risks in the containers, functions, and artifacts that development and engineering teams pass through DevOps workflows and CI/CD pipelines, and provides deep insight into the security configurations of cloud environments. Support regulatory compliance and internal security standards with automated security policy enforcement to detect and preclude security risks as they enter software projects throughout the SDLC.

To learn more about how to leverage Aqua to build cloud native security into your SDLC, download the checklist for build, infrastructure, and runt