Secure Software Development Lifecycle (SSDLC): A Complete Guide

One key insight from our 2024 State of Code Quality report is the increasing emphasis organizations place on security to combat growing cyber threats. The report reveals that 84% of respondents conduct regular security audits. Plus, in addition to having dedicated security teams, 46% provide ongoing security training for developers. 

This heightened focus on security has led to the development of the Secure Software Development Lifecycle (SSDLC). This is an evolution of the traditional Software Development Lifecycle (SDLC) that integrates security considerations into every phase of the development process.

By embedding security throughout the SSDLC, organizations can identify and address vulnerabilities early, reducing risks and costs associated with fixing flaws later in the process.

This article explores the SSDLC, its principles, and how it empowers developers to build secure software from the ground up.

What is the Secure Software Development Lifecycle (SSDLC)?

The SSDLC is a set of practices designed to incorporate security into every phase of the traditional software development process, from initial planning and requirements gathering to design, coding, testing, deployment, and maintenance.

In a traditional SDLC, a separate "security team" often handles security. They test the system for vulnerabilities at the end of the development process. 

However, vulnerabilities that go undetected until late in the development process increase the risk of security breaches, and fixing these issues after development is more expensive than addressing them early on.

The SSDLC shifts the paradigm by placing security front and center throughout development. It turns security from one team's responsibility into everyone's. It fosters a culture where every team member, from developers to testers and operations, is accountable for security. This cultural shift leads to organizational improvements as security becomes integral to the development process.

What are the Phases of the SSDLC?

Implementing the SSDLC requires adherence to key practices that enhance security throughout the development process. Let's explore how the SSDLC addresses security challenges in each phase of the software development lifecycle.

1. Requirements Gathering

Traditionally, the requirements-gathering phase focused primarily on functionality. For example, "We need a login system!"

However, with the SSDLC, the scope expands to include security considerations from the beginning. Now, we're also proactively thinking about:

• Encryption Standards: What encryption standards should protect sensitive data at rest and in motion?
  
  
• Data Storage and Backup: How should data be stored in the database? Where should it be stored geographically to comply with data sovereignty laws? What backup and data replication strategies should be in place to prevent data loss?
  
  
• Integration with Login Providers: If using a third-party login provider, how do we securely integrate with them? What secure login libraries and frameworks should we use?
  
  
• Compliance Regulations: What compliance regulations should you consider? Depending on the application, this could include PCI DSS for payment information, HIPAA for health data, or GDPR for personal data protection.
  
  
• Secure Data Handling Protocols: What protocols should you implement to ensure the secure handling of user information?

By addressing these questions during the requirements-gathering phase, the SSDLC ensures built-in security from the start of the project.

2. Design 

During the design phase, the focus shifts to identifying potential security threats through threat modeling. This focus involves thinking like a hacker to anticipate where and how an attacker might try to breach the system. 

For a typical software application, you'd look for attack vectors such as SQL injection, cross-site scripting (XSS), cross-site request forgery (CSRF), and other vulnerabilities listed in the OWASP Top 10.

The goal is to ensure the design doesn't inherently allow attackers to gain unauthorized access to data or other business assets within the organization. This could involve implementing secure design practices such as:

• Using prepared statements and parameterized queries to safeguard against SQL injection attacks.
  
  
• Implementing input sanitization and validation to mitigate the risk of XSS.
  
  
• Designing the application with a clear separation of concerns, isolating different components to limit the impact of a potential security breach.
  
  
• Implementing multiple layers (Defense in Depth) of security controls (e.g., firewalls, intrusion detection systems, and encryption) to provide redundancy and protect against threats.
  
  
• Applying the principle of least privilege to minimize the access rights of users and applications.
  
  
• Incorporating secure authentication and authorization mechanisms to ensure only authorized users can access sensitive data.
  
  
• Designing comprehensive error handling and audit logs to trace and respond to security incidents effectively.

3. Development 

In the SSDLC, the development phase is not just about writing functional code but also secure code. Developers must adhere to secure coding standards and best practices to ensure their code does not introduce vulnerabilities. 

Static Application Security Testing (SAST) tools like Codacy can identify insecure coding practices like potential SQL injection flaws. Doing so allows developers to address them promptly before deploying the code.

The security of the development environment is also crucial in the SSDLC development phase. For instance, developers working remotely must use a secure VPN to protect their connections and prevent interception by malicious actors.

Using third-party libraries can expedite development, but it also introduces potential risks. Therefore, developers should only use well-vetted libraries from trusted sources. 

Software Composition Analysis (SCA) and Dependency Checkers, such as OWASP Dependency Check and Codacy, can scan for and alert developers to any insecure or outdated libraries in the software supply chain. Scanning helps mitigate risks associated with third-party components.

4. Testing

At the heart of the SSDLC is "shifting left,"  which moves security testing earlier in the development lifecycle. This approach allows for the early detection and remediation of security vulnerabilities, significantly reducing the cost and effort associated with fixing issues later in the development process or after deployment. 

The SSDLC employs various testing techniques, such as: 

• Static Application Security Testing (SAST): SAST is a technique that analyzes the codebase statically to identify vulnerabilities such as SQL injection and improper language usage before executing the code.
• Dynamic Application Security Testing (DAST): DAST involves simulating real-world attack scenarios to identify vulnerabilities that are prevalent during runtime, such as insecure server configurations.
  
  
• Interactive Application Security Testing (IAST): IAST combines elements of both SAST and DAST, analyzing static code and code execution in real time to detect vulnerabilities like broken authentication logic that SAST and DAST methods alone may not catch.

The continuous integration and continuous delivery (CI/CD) pipeline often integrates these security testing techniques, ensuring streamlined and automated security checks that run with each code build. 

5. Deployment

In the SSDLC, the deployment phase ensures the software is securely configured and ready for production. This means implementing and verifying various security measures before the software goes live to prevent potential vulnerabilities from being exploited. 

Automation plays a pivotal role in secure deployment. Infrastructure as Code (IaC) tools like Terraform, Ansible, and Chef automate the provisioning and configuration of deployment environments. These tools allow for consistent, repeatable, and auditable deployments, reducing the risk of human error and ensuring a uniform application of security controls across all environments.

Secure secrets management is another crucial aspect of the deployment phase. Properly handling sensitive information is crucial in maintaining the security and integrity of your software. 

One common security risk is using hard-coded secrets directly in the code, such as API keys, passwords, or tokens. Additionally, IaC configurations must be secure to prevent vulnerabilities in the deployment environment.

Codacy offers secrets detection and IaC scanning capabilities to analyze your code configurations for security vulnerabilities and misconfiguration before deployment.

With the SSDLC, all deployments must follow a formal change management process. This process includes security sign-offs and compliance checks to ensure the vetting of all changes for security implications before being implemented in the production environment.

6. Maintenance Phase

After deployment, without continuous monitoring and timely patches, applications remain susceptible to evolving cyber threats.

Central to the maintenance phase of the SSDLC is the implementation of a comprehensive vulnerability management program. This program includes:

• Regular security assessments and penetration testing to identify new vulnerabilities that may have emerged since the initial deployment.
  
  
• Continuous vulnerability scanning of both the application and its underlying infrastructure.
  
  
• A well-defined process for prioritizing and addressing identified vulnerabilities according to their severity and potential impact.
  
  
• Ensuring security patches for the application, dependencies, and infrastructure components are promptly applied.

Finally, security is everyone's responsibility and an ongoing process. The SSDLC prioritizes regular security awareness training for application developers and users.

Start Implementing SSDLC Best Practices with Codacy Security

With the cost of data breaches rising, utilizing the SSDLC framework is crucial. By shifting security left and integrating it throughout the development process, organizations can significantly reduce vulnerabilities, cut costs, and improve overall code quality.

Codacy offers a comprehensive suite of security products that seamlessly integrate into your development workflow, making it easier to adopt secure SDLC best practices. 

With Codacy's static code analysis, AI-powered code reviews, and supply chain management tools, you can empower your development teams to start writing secure code from the start. 

Sign up for a free trial today and see for yourself.