Secure Software Development Lifecycle: Stages, Methods & Best Practices  by@intellisoft

Secure Software Development Lifecycle: Stages, Methods & Best Practices

The Secure Software Development concept [emerged in the 1960s] when there was a need to manage complex business systems efficiently. It is a framework that reduces the entire set of procedures for detecting and correcting risks and errors. The US National Institute of Standards and Technology (NIST) [has calculated that Secure SDLC (SDLC) can reduce the cost of fixing vulnerabilities at the design stage by 15 times. The concept has a precise sequence and is divided into six stages of the SDLC concept.
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The products’ quality and success directly depend on the organized development process. In other words, if your goal is high-quality software, then you must have a clear plan and follow it.


SDLC is a methodology that will help you achieve all these goals and significantly reduce your development cost while increasing productivity. It’s a plan that eliminates common bugs and pitfalls by evaluating existing systems for weaknesses.

What Is the Secure SDLC

It is a framework that reduces the entire set of procedures for detecting and correcting risks and errors. The US National Institute of Standards and Technology (NIST) has calculated that Secure SDLC can reduce the cost of fixing vulnerabilities at the design stage by 15 times.

At the same time, it should be understood that Secure Software Development LifeCycle is a classic textbook risk-based approach. Its implementation doesn’t eliminate vulnerabilities completely; it only reduces them to the minimum acceptable level.

Why Does SDLC Matter

SDLC is the best software development and testing solution if you want to fix defenselessness at an early stage.


Secure Software Development Life Cycle includes comprehensive architecture, code, and build reviews. It provides several benefits for your product:

  • Product safety.
  • Awareness.
  • Bugs identification.
  • Cost reduction.
  • Internal business risk avoidance.

In fact, SDLC can steer your workflow in the right direction by reducing risks and costs.

SDLC Practices: A Brief History and Evolution of Models

The Secure Software Development concept emerged in the 1960s when there was a need to manage complex business systems efficiently. Massive corporations tried to develop frameworks to structure massive data, multifactorial processes, and analysis processes.

Also, new secure development models began to appear together with this concept.

SDLC and Application Security

All of our applications can be weak to vulnerabilities in one way or another. This, in turn, can lead to financial losses and provoke customer data leakage.

SDLC security is being applied as a concern at every stage of development. It is a methodology that involves automating software security checks by embedding this process into the application at the development stage.

In fact, Microsoft spoke about this approach to software development in 2004, but companies have only recently begun to resort to SDLC in their work.

This methodology allows developers to identify and fix most vulnerabilities before release, keeping applications secure. Moreover, the cost of this service is several times less than the cost of correcting errors after a low-quality product release.

6 Phases and Processes of Secure Software Development Life Cycle

The concept has a precise sequence and is divided into six stages of SDLC. Of these, the first three phases of SDLC prepare the project and answer the main strategic questions. Meanwhile, the last three stages are optimized to implement the points in the secure SDLC checklist.

Stage 1. Analysis

At this early stage, requirements for new features are collected from various stakeholders. Identifying any security considerations for collecting functional requirements for a new release is essential.

Stage 2. Planning

You will review the security requirements and considerations and answer questions such as:

  • What do you want to do?
  • What should be your final product?

This stage also involves an analysis of possible risks and shortcomings.

Stage 3. Architecture and Design

This is the moment when you and the stakeholders answer the question “How will you achieve your goals in the SDLC security checklist?” that you posed in the previous step. It includes two key steps:

  • High-Level Design (HLD).
  • Low-Level Design (LLD).

Participants also develop data specifications, components, structure, and processing at this stage.

Stage 4. Software Development

Now that you know what you want and how it should look, you can move on to implementing your plan. So, engineers are involved in the process and create a system with the help of code and the necessary technologies.

Customers also have the opportunity to look at the future product and evaluate all the operational functions.

Stage 5. Testing

Quality checks are the next step after its creation. At this moment, you test the technical requirements, all code fragments, device compatibility, and security conditions.

Checks and testing will occur until you receive the product you see in your plans.

Stage 6. Software Deployment

The final stage is where you update and release the application. It is necessary to maintain the app regularly, make the necessary updates, support, change and expand it.

5 Popular SDLC Models and Their Pros and Cons

Today, companies and startups use dozens of different schemes. Each security life cycle model has specific pros or cons. Among them, there are SDLC best practices — the most popular six models used according to a particular situation.


Waterfall Model

It is one of the main and most popular models. It provides organized control over the project. Waterfall Model pros lie in the following:

  • Advanced planning.
  • Minimal risks.
  • Clear structure.

As for the cons, there are not so many of them:

  • This model is not subject to change.
  • Inconvenient for long and complex projects.

This model is easy to understand and implement and has been the go-to model for a few decades (it was formed in the 1970s).

V-Shape Model

This model has become the next step in SDLC models. It was created in Germany in the 1980s for defense projects and provides a more in-depth approach thanks to several features:

  • It separates the phases.
  • Great for time management.
  • Stable testing.
  • Timely detection of bugs.
  • Clear phase separation.

However, the V-Shape Model has some disadvantages:

  • High risks.
  • Difficult to be flexible.
  • It has no prototypes.

This model is ideal for projects where accuracy is critical.

Iterative Model

When the Waterfall model failed to meet the challenge, the IT community created a new scheme in 1975. This was an innovation because the Iterative Model paved the way for new control models.

What advantages does it have:

  • Simple and transparent reporting of the process.
  • Modification flexibility.
  • Adaptability.
  • Low risks.

Of the shortcomings, it has such moments as:

  • Incompatibility with changing requirements.
  • Rigid iterations

The Iterative Model is only suitable for large projects!

Spiral Model

If you are looking for a security system development life cycle model for software with vague requirements, this model is just what you need.

It is a model hybrid that directs a command to accept elements of one or more SDLC models, such as a waterfall or an iterative model. Spiral Model pluses are as follows:

  • Excellent risk management.
  • Flexibility in control.
  • Well-documented focus.

At the same time, it should be borne in mind that this is a relatively expensive model and requires special knowledge and skills.

Agile Model

This is the youngest and most popular system. It is designed to cut down on bureaucracy. This methodology appeared in the 1990s, and today we know about 50 of their types. Why the Agile Model is so good:

  • Flexible system.
  • Rapid reaction.
  • Prompt delivery.
  • Close collaboration between stakeholders.

However, this methodology is not suitable for large teams (15 members or more).

Why SDLC is Useful for Business

Whether you’re building a company, a tool, a complex program, or a completely new product, SDLC is good for ensuring quality and focus on users. Why?

Because it is used for several purposes at once:

  • To help reduce time to market.
  • Providing better performance.
  • Save money and increase the potential value of your product for the stakeholders you care about.

SDLC security best practices are especially helpful in software development because it forces you to work within strict limits.

In other words, it’s a methodology for doing the right things at the right time for the right reasons. The SDLC will get you to follow every step you need to take.

Think of the SDLC as a blueprint for success: blindly following it doesn’t guarantee you anything, but it increases the likelihood of being happy with the results.

SDLC Ensuring and Implementing

What ensures decent app development and SDLC security? First of all, these are suitable sequences and tools:

  • Safe programming practice.
  • Carrying out autotests.
  • Code analysis is dynamic.
  • Pantests for checkings and penetration.
  • Functional testing.
  • Testing protocols.
  • Threat monitoring.

An important role is also played by timely registration for incidents.

Also, a fairly common tool for ensuring secure software development, which can be used at all stages (starting from the fourth in this case), is static SAST. It comes down to code analysis without running the program, which means it is guaranteed to be suitable for development, testing, deployment, and operation stages.

5 Best Secure Software Development Cycle Process Practices


Without going into the full SDLC checklist, you can adopt these five principles to ensure a smooth, secure development lifecycle and optimize your work. The SECSDLC involves which of the following activities? All of them:

  1. Education. Developers should develop skills and knowledge in SDLC and SSDLC for clear guidelines for problem detection and resolution and an understanding of secure coding.
  2. Specific requirements. Explicit requirements are the basis for any secure lifecycle management success. You must be as concise and clear as possible in your recommendations and safety guides. It is important that all project participants offer their solutions.
  3. Development. It applies to everything: the team’s thinking, growth, and communication. Teams are ready for a change in interaction due to SSDLC, so the developers and the security team must work together, allowing each other to fulfill the obligation.
  4. Initiative. It means that you can use additional initiatives like DevOps or DevSecOps.
  5. Priorities. Sort and distribute attention in solving problems. This aims to prevent security issues from entering the production environment and ensure that existing vulnerabilities are sorted out and fixed over time.

So, SDLC — can become your guide, or rather the way to achieve the goal called “cool product.” It is a multi-factor framework that will improve and speed up product development and release and provide reliable app security.


What is a software development life cycle

In short, it’s a detailed plan for safe and proper software development and its support, changes, and improvements.

What are the five stages of software development

There are 5 or 6 known in total (someone shares two phases in one) in the SDLC. This process includes much preparatory work (analysis, creation of requirements) and additional work (testing, deployment), and the most important stage, which is support.

What is the process of software development

This is a set of works and tasks performed by the developer. The process includes work on requirements analysis, design, and programming.

What is the difference between SDLC and Agile

SDLC is a comprehensive software development methodology, while Agile is one of its models.

About the Author

A technology expert and entrepreneur with 20+ years of experience in the web & software development business. Kosta used to occupy various positions, from technical to managerial & executive roles. Worked in both corporate and start-up environments. Currently runs Intellisoft Company as its CEO.

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