Understanding SDLC and How Security Plays Into it
Tags: software, development, security
Published: 2024-02-20 09:28:44


## Table Of Contents
* [General Introduction](#intro)
* [Overview of SDLC](#sdlc)
* [Diving Deeper Into Each Phase](#phases)
  1. [Requirement Analysis](#requirements)
  2. [Design](#design)
  3. [Development](#dev)
  4. [Testing](#testing)
  5. [Operations](#ops)
* [The Importance of Security in SDLC](#sec)
* [Conclusion](#conclusion)

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## General Introduction <a name="intro"></a>

Welcome to the kickoff of my series titled "Secure Software/System Development Lifecycle" or SSDLC for short, where I will take you with me on a journey to explore what SSDLC is all about and why it's crucial for creating safe and robust software. 

In this first article, we'll focus on the fundamental pillars of SDLC and how security plays into it.

#### Let's get started!

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## Overview of SDLC <a name="sdlc"></a>

![banner](https://www.freecodecamp.org/news/content/images/2020/02/SDLC_-_Software_Development_Life_Cycle.jpg)

The SDLC consists of several distinct phases. There are some variations to this but generally we have the following five phases.

* _***Requirement Analysis***_ : This is where we gather all the requirements from the client as to what it is that they want to build.
* _***Design***_ : This is where we pick different technology stacks to work with and make some architectural decisions.
* _***Development / Implementation***_ : This is the fun phase where we actually write code.
* _***Testing***_ : This is where we take the code and run some tests on it to make sure that it :
  * Works (obviously !)
  * Secure (Very important!)
  * Meets the client's requirements.
* _***Operations / Evolution***_ : This is where we deploy the tested code to production environments and maintain it by going through the whole cycle again each time a bugfix or new feature is added.

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## Diving Deeper Into Each Phase <a name="phases"></a>

Let's start by uncovering the details of the Requirement Analysis (RA) phase.

### Requirement Analysis <a name="requirements"></a>


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/744pf43dh7xmmjos18u4.jpg)

In this phase, our job involves engaging in discussions with the client to understand their project requirements and determine what they aim to build. The process generally will go like this :
* Get a high-level overview of the requirements and goals
* Conduct requirement analysis to make sure you understand what those requirements are.
* Have an agreement with the client to make sure what they want is being captured.

⚠️ Often, clients know what they want but do not know how.

* Prioritization of requirements (Differentiate between the ones that the client wants vs the ones that are nice to have).
* Allocating resources ( budget, human resources) to make sure the work gets done.

### Design <a name="design"></a>

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/i2ou7085hblpxecm8jfr.jpg)
In this phase, the high-level system requirements previously gathered are translated into a detailed blueprint for the software solution.
It typically involves the following parts:
* ***Architectural Design*** : includes system architecture, modules, and their relationships.
* ***Data Design*** : includes data model and database structure necessary for the application.
* ***UI/UX*** : Planning the user interface, including how users will interact with the system.

You'll want to make sure to document those design implementations to serve as a guide for the developers during the development phase.

### Development <a name="dev"></a>
![banner](https://cdn.vectorstock.com/i/preview-1x/08/82/software-developer-character-programmer-vector-26310882.jpg)

This is where the developers sit down and translate the detailed design documents into executable code that hopefully works!.

### Testing <a name="testing"></a>


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/qqt0wzbsgo0jwed8gj3w.png)

The primary goal of the testing phase is to identify and fix defects or bugs in the software to deliver a high-quality product.

There are several ways of testing code.

* ***Unit Testing***

This is the process of testing individual units of code, such as functions or classes to verify that each unit of the software performs as designed and to catch and fix any defects or errors early in the development cycle.

* ***Integration Testing***

This is focused on verifying the interactions and communication between different components, modules of a software system to discover and pinpoint defects or issues that may emerge during the combination and interaction of various components.
 
Integration Testing helps uncover errors such as incompatible interfaces, incorrect data transfers, communication failures and so on.


* ***End-to-End Testing***

End-to-end Testing verifies that the software works correctly from the beginning to the end of a particular user flow. It replicates expected user behavior and various usage scenarios to ensure that the software works as a whole. The goal of this form of software testing is to simulate and validate the user experience (UX) from start to finish. The key here is the UX since these tests are designed to catch any bug that any end user of the app could encounter beforehand.

Another key point to note is that End-to-End Testing can be carried out either manually or automated using specialized testing frameworks and tools such as :

- [Cypress](https://www.cypress.io/)
- [Selenium](https://www.selenium.dev/)
- [Playwright](https://playwright.dev/)

⚠️ It's important to highlight that there are specific tests dedicated to security, forming a pivotal aspect of the upcoming articles in this serie.

### Operations / Evolution <a name="ops"></a>

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/oet5t371urcbxclii8ja.jpg)

Once the software has passed testing and is deemed ready for release it gets moved from the development/staging environment to the production environment where it will be used by end-users. Once that is done and the software is in active use, this phase focuses on maintaining and evolving the software to meet changing requirements, address issues, and enhance its functionality over time.

Key activities during the operations/evolution phase include:

* ***Monitoring and Support*** : This includes tracking performance, identifying potential issues, and providing support to end-users.
* ***User Feedback*** : This is essential for understanding how well the software meets user needs. This feedback can inform future updates and improvements.
* ***Updates and Upgrades*** : This could involve adding new features, improving existing ones, or incorporating security patches.


To summarize, so far we've seen a comprehensive overview of the Software Development Life Cycle (SDLC), encompassing key phases such as Requirements Analysis, Design, Development, Testing and Operations.

Now we are ready to move to the next chapter where we will delve into the critical aspect of security within the SDLC.

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## The Importance of Security in SDLC <a name="sec"></a>

Security in Software Development Life Cycle (SDLC) is crucial for creating robust, secure software applications.

Here are some key reasons highlighting the importance of security in SDLC:

1. ***Cost-Efficiency*** : This is the main motive behind identifying and addressing security issues early in the development process as fixing vulnerabilities during the design or coding phase is often less expensive than fixing them in production.
2. ***Risk Mitigation*** : Identifying vulnerabilities and implementing security measures during development reduces the likelihood of security incidents and data breaches during the application's lifecycle.
3. ***Reputation Management*** : Security breaches can significantly damage an organization's reputation. By prioritizing security in SDLC, companies demonstrate a commitment to protecting user data and building trust with customers, clients, and partners.

To implement security in SDLC, we focus on incorporating existing security frameworks, standards, and practices such as OWASP,NIST and DevSecOps. 

Throughout this series, we will extensively explore these frameworks and intertwine their principles into our discussions.


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/iw19tl12esytk3v5cgva.png)


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## Conclusion <a name="conclusion"></a>


In conclusion, the SDLC provides a structured framework for planning, designing, developing, testing, deploying, and maintaining software. Embedding security practices at each phase is not only essential but also fundamental in ensuring the creation of robust, resilient, and secure software systems.

Stay tuned for upcoming articles within this series as we delve deeper into SSDLC