Secure SDLC (Software Development Life Cycle): Why Is It Important?

A software development life cycle (SDLC) framework maps the entire development process. This includes all phases such as planning, designing, building, releasing, maintaining, updating and, if necessary, replacing and retiring the application.

Secure SDLC (SSDLC) builds on this process by building security into all phases of the lifecycle. When moving to DevSecOps, teams often implement an SSDLC. This process includes not only the functional aspects of development but also applying security best practices and protecting the development environment.

Let's take a look at what the Secure Software Development Life Cycle (SDLC) really is and why you should consider adopting one.

The Importance of a Secure Software Development Life Cycle

Businesses compete to be one step ahead of their competitors, and they strive to provide their customers with rapid software releases with innovative features. Creating and developing innovative solutions yourself is a big challenge in itself, not to mention securing the software.

To support rapid development velocity, organizations should build security into every stage of the SDLC, rather than performing security testing at the end. A secure SDLC is an effective way to integrate information security into the development process without reducing development productivity and contrary to the assumption that information security disrupts the development process.

An important part of the SSDLC is to bring together all stakeholders involved in the project to ensure application security, frameworks and practices. They should also consider using automated tools to identify security risks in the code they write and to detect security vulnerabilities in the open-source libraries they support for their projects.

Additionally, the management team can use the secure SDLC as a tool to implement a strategic approach to creating a secure product. For example, managers can perform a gap analysis to gain insight into which security activities or policies are currently in place, which are absent, and how effective they are at each stage of the SDLC.

To achieve an optimized SSDLC and ensure that software delivery deadlines are not exceeded security policies that address high-level issues like compliance without requiring manual review or intervention must be established and enforced. To achieve this, some organizations choose to hire security professionals to assess security requirements and create a plan to help the organization improve their security capabilities.

Incoporating Security Into All Phases of the SDLC

Each stage of the SDLC prompts its own security implementation, tools, and DevOps automation strategies.

Requirement Collection and Analysis

In this phase, the security requirements for the software are defined. Security experts analyze the main security risks with the application, such as B. Functionality, type of information application used, etc. This also includes internal security risk assessment and assessment to avoid future conflicts. For example, if the functional requirement is for users to be able to log in, security considerations include questions like

- Which authentication protocol is secure enough?
- Is multi-factor authentication or single sign-on (SSO) used?
- Do we create authentication ourselves or utilise an external provider?

Architecture and Design

In this phase, security is integrated into the design of the software application. We perform threat modelling, which mainly consists of four steps: application decompression, classification, prioritization and security risk mitigation.

The team must follow the architecture and design instructions from the previous phase and try to manage any risks. Fixing a vulnerability early in the design phase eliminates the need to find and fix it in the more expensive development phase. Processes such as threat modelling and architectural risk analysis make the development process easier and safer. We also plan countermeasures to address identified security threats and meet security requirements.

It is essential to assess third-party software components to ensure that third parties have not introduced their own vulnerabilities into the software. This can prevent devastating attacks in the supply chain.


The development phase consists of writing the application code. In this phase, we ensure that the code is developed securely using the security controls identified during the design phase. Organizations also conduct training for developers to better understand the secure software development lifecycle and enable them to test application security features. Developers' code is also reviewed to ensure that their code does not have any security vulnerabilities.

Additionally, developers must implement design patterns and security frameworks correctly. There must be a clear security architecture for software projects that developers can follow. Development is only considered "complete" if appropriate security models are used.

Furthermore, automated tools should analyze code in real time and notify developers of security issues such as including an open-source library with known vulnerabilities.

Testing and Verification

When the application is under test, it is verified to ensure it conforms to security standards and in-depth security testing is performed including penetration testing, integration testing, additional static code analysis, dynamic analysis, etc.

Typically, automated security tools are deployed as part of a continuous integration/continuous deployment (CI/CD) pipeline with multiple "gates" that determine whether a new version is released. These goals should include:

- Unit tests to verify individual components of the application.
- Functional tests that test critical paths of the application.
- Security testing to determine if important security controls exist and if there are any vulnerabilities in components.
- Ensure that software artifacts do not contain secrets (such as database access information). You must dynamically insert it into the production environment.


During the deployment phase, all security controls are double-checked. Security code (static analysis), dynamic analysis, configuration, container security, etc are checked until final deployment. We then implement an ongoing monitoring and mitigation program to identify security vulnerabilities in running applications and quickly fix them.

Security practices must be followed when maintaining the software. In particular, products must be constantly updated so that all components have the latest security fixes.

Best Practices to Secure the SDLC

Prepare Your Organization

Make sure your organization is well-equipped to develop security software. It starts with defining security requirements for the software to be developed and for the people, processes, and tools that will perform for developing the software.

Then use training activities and management approval to prepare employees. Other aspects of readiness include implementing tools and toolchains to automate the process and safeguarding the environments and endpoints used for development.

Protect Development Infrastructure and Assets

Software source code, configuration as code, and other forms of code must be protected by organizations. However, the way you do this varies depending on the situation:

- Open-source projects only need to protect the integrity of their code to prevent malicious code from being added.
- Proprietary software projects need to protect confidentiality to prevent theft of intellectual property.
- All organizations need to secure their CI/CD pipelines to prevent compromise and sabotage by internal or external threat actors.

Respond to Vulnerabilities

Vulnerabilities are discovered in released software, whether by your own organization, your customers, or security researchers. The public increasingly expects organizations to respond quickly when a vulnerability is discovered in their software. Withholding knowledge of vulnerabilities for weeks or months can seriously damage a software company's reputation.

Prepare to respond to vulnerabilities by having a vulnerability disclosure program and associated policies, analysing new vulnerabilities and quickly deciding how to fix them, implementing and testing software changes, and finding the root causes of vulnerabilities in released software and eliminating them.

It's also important to have robust monitoring in production environments and send alerts when suspicious activity occurs. Incident alerting tools like OnPage can help send alerts to the right people, make sure they're responding, and automatically escalate the alert if needed.


We explained why it is important to create a secure SDLC, demonstrated how to secure all phases of the development lifecycle, and provided three essential best practices for adopting an SSDLC in this article:

- Prepare your organization—remember that the transition to an SSDLC is a cultural change and must involve training and organizational alignment.
- Protect development infrastructure—Ensure the CI/CD pipeline and all related tools are locked and protected.
- Respond to vulnerabilities—because no SSDLC is perfect, make sure you have a policy and process to respond to vulnerabilities in production.

We hope you find it useful as you make the shift to a secure development lifecycle in your organization.