ISC2 Certified Secure Software Lifecycle Professional (CSSLP) Practice Question

In the Waterfall model, each phase offers distinct opportunities to build in security controls. Once functional and security requirements are finalized, the design phase is the best time to perform threat modeling. Threat modeling systematically identifies, ranks, and documents potential threats and attack vectors, enabling architects to design mitigating controls before code is written. Conducting code reviews or static analysis is premature because there is little or no code yet. Dynamic application security testing (DAST) and penetration testing are typically deferred until executable components exist-usually during testing or deployment phases-when the application can be exercised in a running state. Waiting until decommissioning to address threats would miss the opportunity to influence the system's architecture and could necessitate costly rework. Therefore, performing threat modeling during the design phase is the most effective choice.