Application security, or AppSec, is a critical aspect of cybersecurity, focusing on safeguarding software applications against external threats throughout the software development lifecycle (SDLC). As web applications have proliferated, they have become significant targets for cybercriminals, necessitating robust security measures to protect businesses. Common vulnerabilities include SQL injection, cross-site scripting, and CRLF, which can compromise data integrity and security. To address these challenges, organizations can adopt frameworks such as OWASP, NIST Cybersecurity Framework, and ISO 27001, and implement practices like proper developer training, security testing, and continuous monitoring. A mature AppSec program integrates security into every SDLC phase, employing tools like static and dynamic application scanning, threat modeling, and secret detection to mitigate risks. Proactive incorporation of security measures ensures efficient development processes and minimizes delays, while monitoring for leaked secrets on platforms like GitHub can prevent unauthorized access to sensitive information.