Secure application design and development is crucial for protecting sensitive data and systems in the cloud. The Cloud Security Alliance (CSA) Cloud Controls Matrix (CCM) control AIS-04 provides guidance on defining and implementing a secure software development lifecycle (SDLC) process that integrates security requirements throughout the application lifecycle. By following the implementation guidelines in AIS-04, organizations can improve the security posture of their cloud applications.

Where did this come from?

This article is based on control AIS-04 from the CSA Cloud Controls Matrix v4.0.10 - 2023-09-26. The CCM is a cybersecurity control framework for cloud computing that provides a set of security principles to guide cloud vendors and assist prospective cloud customers in assessing the security risk of a cloud provider. For more information on secure application development in the cloud, check out the AWS Well-Architected Framework - Security Pillar.

Who should care?

This control is relevant for:

• Software developers building cloud applications who need to ensure their code is secure
• DevOps engineers integrating security into CI/CD pipelines
• IT security managers overseeing the security of cloud application development
• Compliance officers ensuring cloud apps meet regulatory requirements like PCI DSS, HIPAA, etc.

What is the risk?

Insecure application design and development practices can lead to:

• Injection flaws like SQL injection that allow attackers to manipulate application queries
• Cross-site scripting (XSS) that enables attackers to execute scripts in victims' browsers
• Sensitive data exposure through lack of encryption or misconfiguration
• Broken authentication and session management allowing unauthorized access
• Security misconfiguration leaving cloud systems open to attack Following the guidance in AIS-04 can significantly reduce the likelihood and impact of these risks by integrating security throughout the SDLC.

What's the care factor?

Application security should be a top priority for any organization developing cloud applications that handle sensitive data or perform critical functions. Data breaches caused by insecure applications can result in financial losses, reputational damage, and regulatory penalties. While implementing a secure SDLC process requires investment, it is far less costly than dealing with a major security incident. All stakeholders in cloud application development should care deeply about the security practices covered in AIS-04.

When is it relevant?

A secure SDLC process as described in AIS-04 is relevant for:

• Any application deployed in a public or hybrid cloud environment
• Applications that handle sensitive data like PII, PHI, financial data, etc.
• Mission-critical applications where a breach would have a severe impact
• Applications that need to comply with security regulations and standards

It may be less relevant for simple, low-risk applications with no sensitive data that would not cause significant harm if breached. However, a secure SDLC is still a best practice for any application development.

What are the trade offs?

Implementing a secure SDLC process requires:

• Additional time spent on security requirements, design reviews, secure coding, testing, etc.
• Investment in secure development training for personnel
• Procurement of security tooling for things like static code analysis, dependency checking, etc.
• Extra steps in the CI/CD pipeline to integrated security scans and checks The main trade-off is delivering software more slowly in order to make it more secure. However, identifying security issues early in the SDLC saves time and effort compared to fixing vulnerabilities later and dealing with incidents from insecure software in production.

How to make it happen?

To implement AIS-04:

1. Define security requirements alongside functional requirements in the planning phase. Consider compliance obligations.
2. Train all developers on secure coding practices for your tech stack. Make training part of onboarding.
3. Conduct threat modeling during design to identify risks. Perform architecture and design reviews with security stakeholders.
4. Use a secure coding checklist for each programming language. Perform peer code reviews.
5. Integrate static application security testing (SAST) into the build and CI process to catch issues early.
6. Perform dynamic application security testing (DAST) in a production-like environment during QA testing.
7. Include a security sign-off as part of the release process. Ensure security requirements are met.
8. Scan dependencies and container images for known vulnerabilities before deploying to production.
9. Implement an incident response plan to handle vulnerability reports and breaches. Test it regularly.
10. Monitor application and infrastructure logs for signs of attacks. Investigate and respond to events.

What are some gotchas?

To implement SAST, you need to grant your build pipeline read access to your source code repositories. The build tool needs permissions to pull the repo, run the scan, and write the results back as a build artifact.

DAST requires deploying the application in a realistic test environment, which may require additional compute resources and deployment automation. The DAST tool needs network access to the running application to perform the scan.

Secure coding practices like input validation, output encoding, and using parameterized queries can be tricky to retrofit to an existing application not built with security in mind. It's best to bake security in from the start.

What are the alternatives?

The main alternative to implementing your own secure SDLC is to outsource application development to a vendor that follows a robust security process. However, you are still responsible for ensuring the vendor adheres to your security and compliance requirements.

You could also rely on security scanning and penetration testing after development to catch vulnerabilities, but this is more costly and time-consuming than integrating security throughout the SDLC as prescribed in AIS-04.

Explore Further

• OWASP Top 10 Web Application Security Risks
• OWASP Cheat Sheet Series - Recommendations for secure coding practices
• NIST Secure Software Development Framework (SSDF)
• CIS Controls v8 - CIS Control 16 covers application software security