"The Building Security In Maturity Model (BSIMM) described on this website is designed to help you understand and plan a software security initiative. BSIMM was created through a process of understanding and analyzing real-world data from nine leading software security initiatives. Though particular methodologies differ (think OWASP CLASP, Microsoft SDL, or the Cigital Touchpoints), many initiatives share common ground. This common ground is captured and described in BSIMM. As an organizing feature, we introduce and use a Software Security Framework (SSF), which provides a conceptual scaffolding for BSIMM. Properly used, BSIMM can help you determine where your organization stands with respect to real-world software security initiatives and what steps can be taken to make your approach more effective."
More information: BSI-MM website
Direct download: PDF Document