The Essential SDLC Security Checklist

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Cybersecurity threats are evolving faster than technologies and software development processes, and with each new application a user installs on a device, the attack surface grows. A 2022 report from mobile security vendor Zimperium found that a global average of 23% of mobile devices contained malicious applications in 2021. Although one might think that organizations will have the upper hand with rapid technological advancement, unfortunately, this isn’t always the case. 

There are many ways hackers can compromise devices for reconnaissance or to gain full access to the corporate network resources as if they were authorized users. Ransomware and malware are well-known examples, but flawed code and leaky apps can also set the stage for a breach and further damage. Poor programming practices and flawed code can enable the public, including attackers, to see application data such as corporate information and passwords.

That lesson was clear in 2021 when Slack identified a bug in its Android app that logged cleartext user credentials on devices. The company warned users to change their passwords and purge the application data logs, but the doors were by then wide open to attackers seeking corporate information. More recently, the Beijing 2022 Olympics app, which was compulsory for all attendees, was found to have flaws that could make it easy for hackers to steal sensitive personal information, cybersecurity researchers in Canada warned. To protect against flawed code and leaky apps, organizations must foster secure coding practices and incentivize developers to implement security as an essential part of the SDLC. 

In this blog, we look at what SDLC Security entails before discussing in detail the checklist to ensure a Secure SDLC.

What is SDLC Security?

sdlc-checklist

SDLC, or Software Development Life Cycle, is a systematic process of building software by defining a set of rules from start to end continuously. There have been multiple SDLC models, including the most recent and effective DevOps. 

SDLC Security is a framework for building a secure application by making security a core development requirement right from the app’s inception

Why do we need SDLC Security?

In simplest terms, SDLC security is important to make your application bulletproof (or as close to it as possible). Traditionally, businesses used to release applications, wait till they identify a bug or security challenge, and then address the issue. This led to disastrous results for businesses (reputation loss, financial burden through fines, and risk of a permanent shutdown) and their customers (identity theft, monetary loss, and privacy intrusions).

Against this backdrop, the benefits of a secure SDLC include:

  • Security as a continuous process and not a one-time checkpoint
  • Effective collaboration between all stakeholders
  • Vulnerability detection or logic flaws early in the development process
  • Reduces business risks and other damages
  • Early detection improves efficiency and software development velocity 

7 Phases of SDLC

phases-sdlc

SDLC is a process where you outline each stage and the tasks within that stage. This approach increases process efficiency and resource productivity. The different phases of SDLC are:

1. Planning

Project stakeholders define cost, timelines, targets, team building, and leadership structure. Planning also involves gathering feedback, recommendations, and suggestions from leaders, customers, experts, and other invested parties.

2. Requirements 

Teams are assigned to individual parts of the project, and requirements are defined in terms of what the application is expected to do, its features, and it’s functionalities. 

3. Design 

The design of the software is essentially modeling how the software will work. Its elements include architecture, user interface, platforms, programming, and security practices.

4. Development 

Developers write the code of your application. Although different teams work on individual parts of the project, they use source code management tools to keep track of code changes and collaborate. 

5. Testing 

After the source code is prepared, it is run through a series of tests to identify any flaws, security threats, and bugs. Eliminating glitches and other issues will increase user satisfaction.

6. Deployment 

Make your application available to users through a downloadable application or website link.

7. Maintenance 

Although the development cycle practically ends with deployment, bugs could have passed through the cracks during testing. Maintenance helps to ensure interruption-free service to your customers.

SDLC Security in eCommerce & Finance

In both eCommerce and financial services, time-to-market is a make-or-break factor. For this reason, almost every player in these industries has adopted DevOps practices to accelerate product and feature releases significantly. 

However, faster product releases pose a significant challenge for security teams. eCommerce businesses and financial institutes are prime targets for cyber attackers due to the direct monetary transactions they manage. To avoid serious damage, enterprises must implement security as a foundational element for their SDLC.

Below are four essential best practices:

  • Establish security requirements for your applications
  • Identify potential gaps and risks
  • Align development and security teams 
  • Perform a comprehensive security analysis to identify risk-prone areas

Checklist to Create Secure Software Development Lifecycle (SSDLC)

sdlc-mapping

Build security into each step of the cycle

Rather than being seen as a roadblock in SLDC, security should be baked into each step of the development process in order to accelerate it. Keeping security in mind at every stage of the development process includes: 

  • Assessing risks during the requirements listing stage
  • Reviewing design
  • Analyzing the architecture for potential risk during the design phase
  • Performing both static analysis and dynamic analysis 
  • Interactive application security testing during the development and testing stages

Your development team must be aware of the secure coding practices and security frameworks. This ensures consistency and helps you define a uniform security policy at an enterprise level.

Include security requirements in the planning phase

Along with business, performance, and functional requirements, your development team must also gather security requisites from all the stakeholders before the development process begins. 

With respect to security, you will decide on technologies and languages to use along with best practices to detect and manage vulnerabilities and other hostile code. 

This stage also includes ascertaining if the frameworks are secure with the application environment and checking for compatibility of technologies and languages. All the prerequisites must be properly addressed since running into these issues later could lead to development complications and possibly expose your software to security attacks.

Oftentimes, security requirements are tied up with functional specifications. For example, if the functionality needs a user to enter their password before accessing their account, a security consideration can be that the letters they input become encrypted. 

Prevent downstream security issues with secure design

Software designing is a phase where you document how your software product and its features should be built to align with the technical and business requirements. Developers will use this document to write the source code. 

In terms of security, this forms a critical stage. You must review the code and the design properly to mitigate software defects leading to security risks. If left unresolved, these issues don’t appear in the testing phase since they don’t qualify as bugs.

Security review methodologies like architecture risk analysis (ARA) and threat modeling help you identify flaws in your design. While ARA ensures that your design meets the security principles, threat modeling detects any loopholes in the design that hostile agents can leverage to harm your system.

Follow secure coding guidelines and perform code quality reviews

Conducting an efficient security review of source code is important to weed out any vulnerabilities. The code quality review primarily checks logic errors, specification flaws, and style guides, among other defects. It is done through an automated tool, which scans your source code based on predefined rules, and inspects for insecure code.

Secure coding guidelines are technology-agnostic security rules that must be included in the software development process. It is crucial to implement secure coding practices to avoid cyberattacks. Some of these guidelines are validating inputs from untrusted sources, designing and implementing security policies, following multiple defense strategies, executing the least privilege approach, and adhering to quality assurance techniques. 

Test, test, test

Although you have run multiple security checks at different stages of the process, code testing happens once the code is completed. Once the modules are sent for testing, they are subjected to multiple test paradigms, including security testing, to detect and highlight vulnerabilities. You can employ scanning tools for a variety of tests, such as:

Static analysis: SAST ( Status Analysis Security Testing) tests your source code before it is compiled. It detects vulnerabilities and security risks that could open up your application to potential attacks.

Dynamic analysis: DAST (Dynamic Analysis Security Testing), involves vulnerability investigation while the application is in production, usually testing HTML and HTTP interfaces. 

Interactive application testing: Unlike SAST and DAST, this is a functional test that interacts with your application via an automated bot, human tester, or any other type of simulated interaction. 

Penetration testing: In this test, you evaluate the security of your application by stimulating an attack using tools, techniques, and processes that real-life cyber attackers use.

Keep up with the latest threats

With evolving technology, cyberattack practices also evolve. Therefore it is critical to keep yourself up to date with security issues. Although there are no fixed guidelines on how to do that, you can follow simple practices to ensure that you are always in the know-how of the latest threats on the scene:

  • Follow security experts as they usually spend the majority of their efforts on researching cybersecurity issues. Subscribing to their blogs, newsletters, podcasts, and other updates they release is a good idea.
  • Do your own research into the cyberattacks ecosystem. Although it might not be possible for you to dedicate as much time to this as experts, you can read through every reported attack, such as the Log4j vulnerability, and pore into the details.
  • Attending cybersecurity events is also a great way to learn new trends. Engaging in such events will also help you build a network of security professionals who can collaborate and share knowledge on software security.

Better software security without the additional overhead

Current market demand for improved security has pushed SDLC security to the forefront. Security and reliability are two of the most important factors for delivering a successful application. 

However, building a secure application demands a security-driven approach to software development, and including security best practices as an inherent part of the process can be fairly straightforward. 

We’re helping businesses just like yours ensure the security of their web applications with our cybersecurity platform. It eliminates the hassle of managing multiple tools. Our management dashboard allows one-window deep visibility into all your digital assets, components, and supply chain. If you’re interested in better adherence to your SDLC security, Reflectiz can be a great support.

FAQs

How can development teams stay current with evolving cybersecurity threats during the SDLC?

Development teams can stay current with evolving threats through three practices: following security experts by subscribing to their blogs, newsletters, and podcasts for ongoing research updates; conducting their own research by reading detailed post-mortems of reported attacks such as the Log4j vulnerability; and attending cybersecurity events to learn new trends and build a professional network for knowledge sharing. Since cyberattack techniques evolve alongside technology, keeping teams continuously informed is essential to maintaining an effective SDLC security posture.

How should security requirements be included in the SDLC planning phase?

Security requirements should be gathered alongside business, performance, and functional requirements before development begins. This includes deciding on technologies, programming languages, and security frameworks, checking compatibility and whether frameworks are secure in the application environment, and defining how to detect and manage vulnerabilities. Security requirements are often tied to functional specs — for example, if a function requires password entry, the security requirement is that the input must be encrypted. Addressing these prerequisites early prevents development complications and security exposure later.

What are SDLC security best practices for eCommerce and financial applications?

eCommerce and financial applications face elevated cyber risk due to the direct monetary transactions they manage, making secure SDLC practices critical. Four essential best practices are: (1) establishing clear security requirements for all applications; (2) identifying potential security gaps and risks before development; (3) aligning development and security teams to avoid siloed work; and (4) performing comprehensive security analysis to identify risk-prone areas. Since these industries rely on DevOps for fast releases, security must be embedded as a foundational element — not an afterthought — to avoid breaches that cause financial and reputational damage.

What are secure coding guidelines in software development?

Secure coding guidelines are technology-agnostic security rules that developers must follow during the SDLC development phase to prevent cyberattacks. Key practices include validating all inputs from untrusted sources, designing and implementing security policies, following multiple defense-in-depth strategies, applying the Principle of Least Privilege, and adhering to quality assurance techniques. These guidelines should be part of a uniform, enterprise-wide security policy that all developers are trained to follow — ensuring consistency across teams and codebases.

What are the 7 phases of the SDLC?

The 7 phases of the SDLC are: (1) Planning — stakeholders define cost, timelines, team structure, and gather expert feedback; (2) Requirements — teams are assigned and functional requirements defined; (3) Design — software architecture, UI, platforms, and security practices are modeled; (4) Development — developers write and manage source code using version control tools; (5) Testing — code is tested for flaws, bugs, and security threats; (6) Deployment — the application is made available to users; and (7) Maintenance — ongoing bug fixes and service continuity after release.

What is SDLC Security?

SDLC Security (Secure Software Development Life Cycle) is a framework for building secure applications by making security a core development requirement from the very beginning — not a post-release fix. It integrates security practices into every phase of the Software Development Life Cycle (SDLC), from planning and requirements gathering through design, coding, testing, deployment, and maintenance. The goal is to catch vulnerabilities early when they are cheapest to fix, rather than discovering them after attackers do.

What is the difference between SAST and DAST in SDLC security testing?

SAST (Static Application Security Testing) analyzes source code before it is compiled — it finds vulnerabilities in the code itself without executing the program. DAST (Dynamic Application Security Testing) tests the application while it is running in production, probing HTML and HTTP interfaces to find runtime vulnerabilities that do not appear in the static code. In a secure SDLC, both are used together: SAST catches code-level flaws early in development, while DAST validates security in the live environment.

What is threat modeling in the context of SDLC security?

Threat modeling is a security review methodology applied during the SDLC design phase that identifies loopholes or attack vectors in the software architecture that hostile agents could exploit. It works alongside Architecture Risk Analysis (ARA) — while ARA verifies that the design meets security principles, threat modeling proactively finds design flaws before code is written. By applying threat modeling early, teams avoid vulnerabilities that will not surface as standard bugs during testing, making them particularly dangerous if left undetected.

What security testing types are used in the SDLC testing phase?

The SDLC testing phase uses four main types of security testing. Static Analysis (SAST) tests source code before compilation to detect vulnerabilities. Dynamic Analysis (DAST) tests the application in production by probing HTML and HTTP interfaces. Interactive Application Security Testing (IAST) uses automated bots or human testers to interact with the running application. Penetration Testing simulates real-world cyberattacks using the same tools and techniques attackers use to evaluate the application’s security posture.

Why is SDLC Security important for businesses?

SDLC Security is important because releasing applications without built-in security has historically led to severe consequences: reputation damage, regulatory fines, and risk of shutdown for businesses, and identity theft and financial loss for users. A notable example is Slack’s 2021 Android app bug that logged cleartext credentials on devices. Integrating security into every phase of development prevents these outcomes by detecting vulnerabilities and logic flaws early — when they are far cheaper and easier to fix than post-release patches.

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