This document discusses security testing performed for a client that provides background screening and immigration compliance services. The key challenges included testing an application with detailed user information, frequent changes, and complex user classifications. Security testing was needed to identify vulnerabilities in the application's authentication, integrity, authorization, confidentiality, availability, and non-reputation. The engagement involved analyzing the security architecture, identifying threats and vulnerabilities, developing test cases, and executing tests using tools like Wireshark, WebScarab, Burp Suite, Nikto, and Nmap. Major vulnerabilities around injection, authentication, sensitive data exposure, and more were identified and addressed.