
Software now sits at the heart of every modern enterprise—from automakers to financial institutions. But as organizations race to innovate, speed often outpaces security. Agile methodologies, cloud-native architectures, open source, and microservices have transformed how applications are built and delivered, but they’ve also introduced greater complexity and risk. Application, infrastructure, and cloud security are increasingly interconnected, making a unified, mature approach to software security more essential than ever.
In 2023, members of the Purple Book Community came together to assess the strengths and limitations of existing software security maturity models. The result of their collaboration is the Scalable Software Security Maturity Model (S3M2)—a new, community-driven model designed to help organizations navigate their evolving security posture with greater clarity and confidence.
First introduced at AppSecCon 2023, S3M2 builds on prior models while addressing key gaps identified by practitioners across industries. Developed by experts, for the community, S3M2 offers a practical path forward on the journey to application security maturity.