Secure Software Development Life Cycle | SSDLC


Secure software development life cycle includes the implementation of security workflows and security testing throughout the entire life cycle of software development and includes the use of secure coding methodologies, secure code reviews, penetration tests, vulnerability analyses, and threat modeling.

Security analysis of the software is introduced throughout the entire development process to ensure that applications are developed in a secure manner from beginning to end. This gives security engineers a good look at all attack surfaces at every stage of the life cycle and allows developers to remediate vulnerabilities before the application is sent to production.

Many current organizations employ an end-of-life-cycle penetration test and security audit on a completed application or set of features, which often makes it difficult (and much more expensive) to remediate security coding errors.

Since many developers are tasked with producing code that works - and not code that is secure - the result is technical debt.

Much of the problem is the disconnect between security engineers and developers, and the lack of security awareness on an organization level. Many executives are unaware of how insecure their applications are, resulting in a lack of time and direction given to developers to properly remediate security vulnerabilities. According to recent a study 47 percent of software developers have stated that they are given no mandate to remediate security vulnerabilities - 29 percent of security engineers said the same.

Furthermore, because most data breaches occur due to flaws in the applications, and application security consumes less than 20 percent of most corporate IT security budgets, many companies do not want to invest in changing the complex code of an application after the development of the app has been completed. For this reason, security needs to be incorporated into every step of the application development life cycle, from beginning to end.

This is in stark contrast to many modern workflows, where few developers and security professionals feel that security is adequately addressed during the design and development phases of application development. Analyzing and identifying vulnerabilities - and mitigating them - throughout the entire development life cycle and implementing secure coding and security testing throughout the SDLC are a necessity.


Each phase of the software development life cycle should have security at its core. There are several SSDLC models (e.g. Microsoft SDL, OWASP CLASP, OWASP Software Assurance Maturity Model, etc.) that provide a methodology for securing an application from the application conception to the end of its development.

  • Each of the major development steps in an SDLC can be augmented with security. The primary steps are:Requirements Gathering - determining what the application will do and the goals for the system.
  • Planning and Design - setting forth the blueprint of the application, determining the components that will be translated into modules and functional libraries, etc.
  • Development - putting the blueprint into practice (development of the source code) via programming languages.
  • Verification and Testing - testing the implementation of the source code for bugs, issues, functionality, performance, etc.
  • Release and Maintenance - releasing the application and deploying it into production.



The coding of a web application - including both the front-end and back-end - determines how secure your web application will be, and how well it will hold up against an offensive front. Weak code introduces security holes (vulnerabilities) that can be exploited by a cyber-attacker.

Software engineers need to identify the vulnerabilities found in each programming language that they use to develop web applications. Insecure coding practices increase the overall risks to your business assets, and passes those security risks onto all end-users who utilize your web applications.

Protecting yourself and your customer base is necessary, and is a goal that is achieved only when using comprehensive security assessments, such as code reviews, that will ensure that your web application's entire attack surface is adequately protected.

The effectiveness of a manual, static code review lies in its potential to identify poor coding practices that could introduce high-risk security holes into your web application.

From a security perspective, it is important to note that the weakest link of any application is the end-user and its developers - people. Most developers feel that security is simply not addressed during the SDLC.

Even more, it has been noted by several reports that developers are often not trained in security methodologies at all, while research shows that 80 percent of cyber-attacks are basic and can be avoided by offering security training to developers. For this reason, a Secure SDLC adds another step at the beginning of the model:

  • Security Training - Core Security as well as Specialized and ongoing training for all project team members throughout the project.

The disconnect between developer coding methodologies and secure coding protocols is a significant problem - training all development staff on security protocols - including software engineers, QA testers, product owners - can help to mitigate many of the vulnerabilities that often exist in applications. In addition to staff training, it is imperative that security engineers assist with all stages of the SDLC, such as with security audits, penetration tests, code reviews, etc.

It is also necessary to determine and proactively integrate necessary security requirements - centralized security controls - in an appropriate manner, one that results in an efficient security architectural scheme that is easy to manage & review, and one that ensures the completeness of the security controls & the optimal application of those controls.

In addition to above, several protocols and tools should be used in order to properly integrate Secure Software Development Life Cycle strategies into current SDLC protocols.

Threat Modeling - which has been described above - architectural risk analysis (determining application vulnerabilities and identifying risks to corporate assets resulting from those issues), and tools such as automated static analysis and automated dynamic analysis should be used. Automated testing tools are invaluable tools that can help to scan the source code (static) for debugging purposes and to ensure that the code meets certain standards.

Such automated tools can also aid with scanning and testing applications during run-time (dynamic) in order to debug & test the code's implementation. Secure code review (static) and application penetration tests (dynamic) are two methodologies that should also be used during the entire software DLC & integrated into current workflows in order to ensure that software is built with security in mind from beginning to end.

Code reviews allow security personnel to conduct an in-depth review of the code to ensure that no vulnerabilities are present, while penetration testers seek to actively probe and penetrate an application by bypassing security measures & controls.


The entire process detailed above can help to ensure that software is secure from the ground up, which can help to mitigate data breaches that occur through vulnerable applications. It has been noted that it costs 30 times more to fix a vulnerability that is caught post-production versus one that is caught during the earlier phases of the SDLC.

Determining security requirements early on and integrating them correctly, along with:

  • efficiently training developers in the craft of secure coding,
  • determining a secure design and architecture of the software application,
  • enabling developers to use powerful tools to find and quickly remediate security issues during the coding phase,
  • utilizing app penetration tests to quickly identify security issues earlier in the life cycle (thus saving time that is often wasted post-production)
  • conducting thorough security reviews, etc.

These all help to establish a Secure SDLC that could potentially save your company millions of dollars.