A penetration test is a simulated attack against your application to check for exploitable security issues.
Why Penetration Testing
Penetration testing performed on a running application. As such, it tests the application E2E with all of its layers. It's output is a real simulated attack on the application that succeeded, therefore it is a critical issue in your application and should be addressed as soon as possible.
Applying Penetration Testing
Many organizations perform manual penetration testing. But new vulnerabilities found every day. Therefore, it is a good practice to have an automated penetration testing performed. To achieve this automation use penetration testing tools to uncover vulnerabilities, such as unsanitized inputs that are susceptible to code injection attacks. Insights provided by the penetration test can then be used to fine-tune your WAF security policies and patch detected vulnerabilities.
Penetration Testing Frameworks and Tools
OWASP Zed Attack Proxy (ZAP) - OWASP penetration testing tool for web applications.
Penetration testing is essential to check for vulnerabilities in your application and protect it from simulated attacks. Insights provided by Penetration testing can identify weak spots in an organization's security posture, as well as measure the compliance of its security policy, test the staff's awareness of security issues and determine whether -- and how -- the organization would be subject to security disasters.