What is the Secure Software Development Life cycle?


Security is one of the most important features that every software application or product must-have.

Security is not only to protect the applications and products from network threats by securing the networks and connections, but it matters at the applications and product-level also.

We are familiar with the SDLC as software development life-cycle. We have many stages in SDLC and we have many models to implement. Each of these stages involves team members to sit and come up with ideas and solutions.

SDLC we have different stages as:

  • Requirements gathering.
  • Refinement
  • Design
  • Implementation
  • Finally Testing.

Secure Development Lifecycle is kind of add on to each of these stages where we embed the security review into each of these stages. At each stage, we consider the threats and attacks that may have an impact on our application or product and try to make it as secure as much at each stage of development by applying the security techniques.

As a Development team we can use different SDLC models

  • Waterfall
  • Iterative
  • Agile

Software development steps will mostly be common or the same. Each of those steps can be enhanced with the security review.

Importance of Security Review in SDLC

This simple security review will save a lot of time and cost that we may need to invest if we find the same problems at the later stages when our product of application is almost in the hands of end-users.

So, making security review as a continuous process as we keep developing our application is known as Secure Software Development Life cycle.

Customer Expectation

Today customers want the applications and devices which they are using to be safe and secure from

  • Threats like data theft
  • Network attacks,
  • Phishing etc.

To provide a secure application or product to customers it is important for the manufacturers and developers to consider the security of product and application from day one.

Existing Development Model

With existing models of software development, we focus on security when we are in the final testing phase.

In some cases, we find risks at the testing phase that are hard to fix or require a lot of rework or even re-design. This kind of past experience forced us to include security as part of the Development life cycle itself.

We follow security best practices to make the best possible solutions for our products and applications are just the model to standardize these best practices and allow them to be embedded in our process of software development.

Each stage will consider security as an important factor to pass that stage and we will be more comfortable with security challenges when our product is ready for production.

Industry Challenge

The lack of a secure approach while developing application or product causes trouble. Once your product is shipped and is in the hands of customers, you may find issues of security threats.

Now at this time, you need to address these issues on priority when all your resources are already booked for new products and applications and then you lose resources to the tasks which you could have handled better in the initial phases of your product development.

It depends on the problem level also which decides how big is the impact and how much it will cost you.

If you do not make secure development as part of the process that is common for your all products and applications then you face the same problems again and again since each time you have a different team and resources who actually developed the product.

With continuous issues that you face in your products, your customers start feeling unsafe with your products and applications and they tend to move away from you.

Security in SDLC

Security is the feature that our application must have so it should be the topmost requirement when talking about requirements. We start the application of the product with the concept review followed by the details of the requirements.

Secure Requirement Phase

When we work on the requirements gathering phase of SDLC, we must start considering the security starting from this first stage itself.

Let us consider an example

If our application or product will deal with sensitive data then we define our requirements keeping things in mind like how we will protect and ensure data security, so it is not visible to any attacker or threat.

In the requirements phase, we review our requirements to judge the scope of work and the details of work that we are planning to take on. In this phase, we should review the security requirements also to make each of our features safe and secure which ultimately will help us to build a secure application or product and also we define the scope of the level of security we will need for our application or product.

Requirement to pass the Certification based on application type

Now depending on your product type and the industry this product belongs to, we may have some requirements to have certain certifications passed before we can even launch our application for example for payment application and card application we have to get PCI or PA-DSS compliance certifications.

When we discuss requirements at the functional level then we come across detailed requirements that further helps us to implement security.

Once we finalize the requirements then we move to the design phase where we work on our architecture.

Secure Design Phase

Designing a secure architecture is important and this gives us opportunity to shut all the open doors which can lead hackers or attackers to attack your application or data theft.

At this phase we consider threat modeling to make our design robust and safe. We work on determining threats and the weak areas where we could face a security challenge.

Then we cover each of these areas in our design so we can proceed to the next stage which is the actual coding or implementation.

Applying the threat modeling techniques at the design phase helps us achieve the below objectives:

  • It helps us to find security flaws in our design and gives us the opportunity to fix them even before we introduce them.
  • It helps us to save time that we may need to invest later when it is too late and save the reputation of our product or application.
  • It helps us to build a secure application design and baseline.
  • It helps our developers with clear security objectives so they can develop applications accordingly.
  • It helps us to document all the possible threats that our application may face, and it helps us to document solutions that we are doing pro-actively to secure the application.
  • It also helps us to study all existing challenges that we faced in past and new challenges that we may face in the future in terms of risks and threats.
  • It helps us in determining the training and learning requirements also which we may need for our team who will be working on the product or application.

Secure Real-time development of application

The next phase is actual Development of application. Since we have included the security objectives in our requirements and in Design phase then the life of our developers is easy to follow the design to meet the defined security targets.

As a developer at this development phase, only the following requirements, and the following design are not enough. As a smart Development team who values security

Techniques consider for secure Develeopement

  • Secure coding like signing the code with digital signatures.
  • Developing the code with secure executables like secure DLLs(Dynamic Link Libraries) etc.

A lot of languages and technological strategies are available to make the code safe.

At the same time, we refer to the requirements and the areas which we defined in our requirements like data security and critical data which we should not save anywhere in application coding to make it available for attackers to steal.

Secure development Testing

Along with Development testing become the most important phase for any product, but for developing secure product testing needs to be done for all security risks.

Testing phases for security features start with the development itself which includes static code analysis, peer reviews of the source code itself.

In the hands of the professional testers, the application should pass the risk and threat analysis checkpoints, and then the most important part is the penetration testing should be performed.

Penetration testing assures the developers that their code cannot be penetrated by any possible risk or loanabilities.

Some of the available standards available for the secure development lifecycle are:

  • Microsoft Security Development Lifecycle: Microsoft provides the set of security and privacy requirements for Developers to help them during the entire software development life cycle.
  • NIST 800-171: NIST provides the international information security standards which help with the methods, best practices, and techniques that can be used during the entire software development lifecycle.
  • OWASP SAMM: Open web application Security Project software assurance maturity model helps to make strategies that help in the development and deployment of secure applications.


In the end, what matters is the security level of your product or application. Customers do not want to lose data or money with security issues. SDLC is a normal practice that every software development team is following, but what makes a difference is the SDL, which provides more assurance to the customers who are the end-users of the product or application.

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