OWASP Software Assurance Maturity Model

Design
Design concerns the processes and activities related to how an organization defines goals and creates software within development projects. In general, this will include requirements gathering, high-level architecture specification and detailed design.

Threat Assessment
The Threat Assessment (TA) practice focuses on identifying and understanding of project-level risks based on the functionality of the software being developed and characteristics of the runtime environment. From details about threats and likely attacks against each project, the organization as a whole operates more effectively through better decisions about prioritization of initiatives for security. Additionally, decisions for risk acceptance are more informed, therefore better aligned to the business.
By starting with simple threat models and building application risk profiles, an organization improves over time. Ultimately, a sophisticated organization would maintain this information in a way that is tightly coupled to the compensating factors and pass-through risks from external entities. This provides greater breadth of understanding for potential downstream impacts from security issues, tradeoffs, or flaws, while keeping a close watch on the organization’s current performance against known threats.