Secure Software Development Life Cycle (SSDLC)

Over the last few years, there has been exponential growth in the amount of software available. Software has become an integral part of everyday life. It is used in almost all occupations, for entertainment, and as an aid in our daily chores.

As a result, the software has a lot of information about us that needs to be secured. If not done, it can lead to data theft or financial loss at both the individual and organizational levels. In fact, at the organizational level, it can also lead to loss of customers, withdrawal of stakeholders, complaints, or lawsuits.

If we go by statistics, a report by RiskIQ says that security vulnerabilities can cost major companies $25 per minute, and cryptocurrency-based companies lose up to $2,000 per minute due to cybercrimes. Another report by Positive Technologies states that around 64% of applications face the threat of data breaches, of which 82% are vulnerabilities due to coding mistakes.

So, let’s dive into the inevitably required SSDLC.

What is SSDLC?

Lately, there has been an upsurge in the number of software developers, as there are numerous startups and firms in this domain and even more freelancing opportunities. In my previous role as a developer, I observed the whole software development process followed in a development company of around 200 employees. Unfortunately, there were neither any security guidelines nor any designated employee responsible for security. Almost every developer just focuses on understanding the requirements of their client and starts implementing code. There is very little awareness about security in development, be it websites or applications.

SSDLC, or secure software development life cycle, is a framework that incorporates security in all the stages of software development. SSDLC helps in making everybody responsible for software security. This leads to software development that is secure from the start itself. It helps in finding security vulnerabilities in the early stage and fixing them before they reach production. In case some vulnerabilities are not recognized earlier and the software gets breached, the attack will have a lesser impact than it would have in software developed with traditional SDLC.

Transition from traditional SDLC to S-SDLC

Traditional SDLC is best for generating the best quality and low-cost software. It also takes the least time possible. It offers a structure and flow that enterprises can follow to get high-quality and properly tested software. It includes the following phases: planning, analysis, design, coding, testing, and maintenance. All of these phases are followed sequentially and are equally important. In this traditional way, security is dealt with in a “penetrate and patch” (P&P) method. It means penetrating fully developed software and then creating patches for the found vulnerabilities. It not only takes more time to create patches but also increases the cost of development.

The other reasons that contribute to the requirement to switch to S-SDLC are the trends in coding practices. There is an excessive use of third-party components, like libraries which might have a known vulnerability. These vulnerabilities also arise due to the inclusion of newfound technologies like the Internet of Things (IoT) and cloud computing.

Secure SDLC, on the other hand, is like eradicating a problem from the root. It means to start thinking about cybersecurity from the planning stage or even before that. It is not just about having security employees but having a security mindset for all employees. It is about teamwork towards a desired level of security and emphasizing it just as much as is done on quality or coding standards. This can be achieved by modifying all SDLC phases and using different tools according to the security requirements of the software.

Phases of S-SDLC

Secure SDLC doesn’t have some new security phase. It is rather like weaving in security in each step of the SDLC. This can be achieved by following a set of best practices and leveraging technology through automated tools. Let’s discuss all the phases in detail before understanding practical solutions.

Requirement Planning

In SDLC, requirement planning is about talking to stakeholders and collecting all the functional and non-functional requirements. To implement SSDLC, we need to assemble security-related requirements by performing risk assessment and compliance analysis. This can be achieved by asking questions like these:

• What are the security requirements for this project?
• What are possible vulnerabilities?
• If there is a similar project going on, what are the vulnerabilities it is facing?
• What can be done to test the vulnerabilities collected?
• Does this project require user awareness? Can it be used in phishing or social engineering attacks?

All of these questions should be considered by the security team. It helps in identifying what security protections need to be designed for this software.

Design

The design phase is used to visualize how the software will look after implementation. It is to check whether it fulfills all requirements. So, a system architecture is made in the design phase of SDLC. In S-SDLC, it is checked that the system architecture created is actually secure. This can be achieved by performing threat modeling. Some of the questions that can help are:

• What are the third-party assets required? What vulnerabilities do they contain?
• What all APIs are going to be used? Are they going to be public?
• What functions and methods will be dealing with data or a database?

All these questions help to implement secure data flows and robust authentication and authorization mechanisms. The secure design ultimately leads to secure software.

Coding

Now is the time to implement. Coding is the phase where developers turn visualized design to reality. A few things that can help in secure coding are:

• Follow secure coding practices
• Implement according to the security architecture discussed in the design phase.
• Stay updated about security standards and guidelines.
• Check for vulnerabilities before using any libraries and frameworks.
• Regular code reviews to spot security flaws beforehand
• Using automatic static analysis tools to identify potential vulnerabilities

Testing

Testing is a critical phase. There are different types of testing methods, like unit testing and regression testing, that are followed in SDLC. Testing needs to be rigorous to make the software secure. In addition to static analysis tools, there are other tests like penetration testing and dynamic testing. In penetration testing, the red team members of security simulate a real-world attack to discover vulnerabilities. Dynamic testing is one where code is executed, and its behavior is analyzed to identify runtime vulnerabilities.

This phase helps in finding and fixing vulnerabilities before the code is deployed.

Deployment

Deployment means to release the software into the production environment. This phase should be carefully observed for data security and privacy. Secure deployment practices include:

• Securing deployment infrastructure
• Appropriate access control
• Continuous monitoring for any sign of compromise
• Ensuring compliance with code regulations

Maintenance

The work of a developer does not end with the deployment of their software. Maintenance is very similar to service given to cars after purchase, equally important as deployment.

Maintenance generally involves finding and fixing flaws in code, but it is also the point where new vulnerabilities come to light. It would be foolish to think that a secure code always stays secure. This is because the security landscape keeps changing with new threats and zero-day exploits.

These vulnerabilities should be regularly patched, and the software should be monitored continuously to watch for security issues. This shows the need to have a process in place to identify problems and patch them easily for SDLC to be secure.

Go Back to Start

As the image above shows, secure SDLC is a continuous process of improvement. This means that every bug found starts off a new cycle from requirement planning.

Best Practices for S-SDLC

From the previous topic, we know that to implement S-SDLC we need to integrate security in every phase. Now, let’s discuss what practices can assist us in doing that.

1. Data Protection

• Encrypting files: All the data at rest, such as backups of databases, should be stored in an encrypted version to maintain its confidentiality.
• Audit servers: Regularly audit servers to monitor who has accessed or modified confidential information to preserve the integrity of data.
• Access management: Now for handling availability, there should be strict access and privilege management policies. These policies ensure that no employee gets access to data more than what they require to accomplish their tasks. The policies are also helpful in revoking excessive privilege after the task is completed or revoking all access when an employee changes his role or leaves the company.

2. Security monitoring

• Intrusion Detection System (IDS): Use IDS tools to monitor network traffic for any malicious activity or policy violations.
• Proactively detect threats: Utilize a security analytics and threat intelligence platform that consists of the following:
  Extended Detection and Response (XDR) tools for already known attacks
  Security Information and Event Management (SIEM) to monitor logs using custom detections
  Security Data Lake for long-term storage or archiving old logs

3. Secure coding practices

• Follow secure coding standards: Adhere to the latest secure coding rules to avoid obvious vulnerabilities.
• Secure system architecture: Keep security in mind while designing systems.
• Heed your compiler: Pay attention to warnings given by your compiler, as they can indicate security issues.
• Keep it simple: Keep the code simple, as that reduces complexity-related vulnerabilities and also makes it easy to make security patches.
• Validate and sanitize data: Always validate data when taking input to prevent injection attacks. And sanitize that data before sending it to other systems to prevent leakage.

4. Security tests

• Static Analysis Security Testing (SAST): SAST is used to analyze code before it is compiled. It looks for known problems in code and its adherence to coding standards. Some good examples of SAST tools are CodeQL by GitHub, DevSkim by Microsoft, and ApplicationInspector by Microsoft.
• Dynamic Analysis Security Testing (DAST): DAST tests the application that is fully compiled and after all components are integrated and executed. This testing is mostly done using a suite of attacks or tools that try to replicate an attacker to some point by testing the application’s behavior in situations like memory corruption, access, and privilege issues.
• Application penetration testing: Penetration testing is carried out by skilled security professionals by simulating real-world attacks. The professionals mimic hackers to expose vulnerabilities of all different types, from coding errors to operational deployment weaknesses.
• Run a bug bounty program: A bug bounty program is an event where ethical hackers are rewarded for finding significant vulnerabilities that can have a tragic impact on a system.

Tools and Technologies for S-SDLC

1. IriusRisk

As we discussed in the design phase, threat modeling is critical for S-SDLC. IriusRisk is an automated threat modeling tool. It helps teams find and fix security risks in the early stages of S-SDLC based on system architecture and a few questions. It is also easy to scale out threat modeling across large organizations reducing manual record-keeping traditionally required.

2. Semgrep

Semgrep is an AI-backed SAST tool. Its name is made by fusing two words, “semantic” and “grep”. Semantic shows its ability to understand code in over 17 languages. While grep is a Linux command for searching text and patterns, it reflects Semgrep’s capability to look for patterns, unlike traditional SAST tools that rely on string matching. Its plus point is that it is easy to understand for developers, even those with less knowledge of security. It also provides features like custom rule creation and automatic security checks in the continuous integration/continuous deployment (CI/CD) pipeline.

3. Zed Attack Proxy (ZAP)

ZAP, a DAST tool, provides a proxy server setup through which all the website traffic is routed to find vulnerabilities by real-time scanning. Created by OWASP, it has massive community support and seamless integration with the CI/CD pipeline. It is a penetration testing tool that can be used by organizations of any size.

4. GitGuardian

Most developers use GitHub, a web-based platform for storing, managing, and sharing code. While pushing code on GitHub, there is a possibility that some sensitive information also becomes public. GitGuardian is a tool that automatically detects confidential data like API keys, tokens, or credentials. This protects organizations from costly data breaches. The best thing about this tool is that it gets integrated into the existing workflow and scans repositories, commits, and pull requests in real time without disturbing the developer’s flow.

5. Trivy

This tool is for those organizations that develop cloud-native applications. These applications are stored in containers on platforms like Docker, Kubernetes, etc. Trivy provides vulnerability detection and security analysis for these containers and applications. It ensures compliance and security best practices by scanning Kubernetes workloads for any risky setting. It also examines security configuration in Infrastructure as Code (IaC) files, like the manifest file of Kubernetes. Lastly, it can be easily integrated into the CI/CD pipeline of DevSecOps too for fast scanning with low false positives.

Conclusion

The secure software development life cycle has become a must in today’s interconnected world. It has a few challenges, like time and cost constraints, a lack of skilled professionals, and difficulty integrating in an Agile environment. The benefits of integrating security in all stages of development far outweigh these challenges. S-SDLC aims for the long-term success of applications by finding vulnerabilities and threats in the early stages where they are easy to fix. The ongoing research in AI-assisted security and enhancing tools will be helpful in overcoming the challenges of applying S-SDLC. One more important thing is training employees on cultivating a security mindset.

To provide a visual summary of this long blog, I have attached an image below. It encapsulates tasks, issues, and mitigation practices of each phase of SDLC to make it secure.

Written by: Virti Mehta