The Life-cycle of Security Testing is a structured process designed to safeguard applications, networks, and systems throughout their development and usage. It begins with requirement analysis, where business objectives and potential risks are carefully understood. This is followed by threat modeling, which helps in identifying possible attack scenarios and prioritizing critical areas of concern. Once the risks are defined, detailed test planning is carried out to establish the scope, tools, and methodologies that will be applied. Test cases are then developed to simulate real-world attack situations, including penetration testing, vulnerability scans, and code reviews. In the execution phase, these tests are performed to uncover weaknesses and hidden flaws in the system. Every vulnerability discovered is assessed, categorized by severity, and documented in a clear and actionable report. The remediation phase involves fixing the identified issues, followed by re-testing to ensure the vulnerabilities have been properly resolved. Further validation is conducted to make sure that security fixes do not introduce new risks into the system. Beyond the remediation process, continuous monitoring and regular audits are performed to ensure ongoing protection against emerging cyber threats. By following this lifecycle, organizations can maintain a strong security posture, achieve compliance, and build user confidence in the safety of their digital platforms.