Secure SDLC, SAST, and DAST Tools

The Secure Software Development Lifecycle (SSDLC) integrates security activities into every phase of software development — from requirements through design, coding, testing, deployment, and maintenance. The traditional SDLC treats security as a final-stage gate, which is expensive and ineffective. The secure SDLC philosophy is to find and fix vulnerabilities as early as possible, because defects caught during design cost far less to fix than those found in production.

Shift left means moving security earlier (to the left on the development timeline) rather than bolt it on at the end. In practice, this means including security requirements in user stories, conducting threat modeling during design, performing code review and SAST during development, and running DAST before release. Teams that shift left discover vulnerabilities when they are cheapest to fix — during development, not in production.