In the past decades, web applications have become a vital part of our daily activities, while hacking activities have also increased speedily. Both individuals and organizations are collectively facing significant challenges in securing their applications due to the high rise of threats and attacks. It is now expedient for developers to look for loopholes in authentication techniques to prevent attackers from exploring such weaknesses. Vulnerability Assessment and Penetration Testing have proven to help organizations determine if their security measures are working perfectly. Hence, it is crucial to ascertain these flaws and install security patches to mitigate them. This study illustrates a non-intrusive systematic overview of various knowledge-based authentication techniques, vulnerabilities, and attacks. It also describes the significance of data, the effects of vulnerabilities over data, and the tools used in detection and prevention. Finally, it focuses on creating awareness and the importance of adopting up-to-date security measures to stay protected from attacks.