Penetration testing simulates real-world attacks to ensure vulnerabilities have been addressed and no residual weaknesses remain. "Penetration testing provides assurance that implemented controls effectively mitigate identified vulnerabilities and that no new exposures have been introduced." - CISM Review Manual 15th Edition, Chapter 3: Information Security Program Development and Management, Section: Testing and Evaluation* The ISACA practice database consistently recommends penetration testing for validating that vulnerabilities are closed.