Applications are often the most exposed layer of an organization’s attack surface, and defending them requires both proactive development practices and reactive protection mechanisms. In this episode, we review essential application security concepts including input validation, secure cookie handling, and session management to prevent injection attacks, cross-site scripting (XSS), and session hijacking. We also examine the importance of static code analysis during development, code signing to verify integrity, and the use of secure development lifecycle (SDLC) frameworks to build security into every stage of application delivery. Runtime protections such as web application firewalls (WAFs), rate limiting, and sandboxing further defend against exploitation in production environments. Secure applications are not born by accident—they are the result of intentional planning, testing, and monitoring. Application security must be part of the culture, not just the code.