The Secure SDLC is a framework for introducing various aspects of application security – secure coding, security testing, remediation of vulnerabilities, etc. – throughout an organization’s existing SDLC. The idea is to better build security into the application by building security processes into the development cycle.
depending on your development methodology (waterfall or agile) and current processes. These include Microsoft’s SDL, the first of it’s kind, and a great place to start for waterfall-based development processes, along with NIST’s 800-64, Security Considerations in the System Development Life Cycle.