Penetration testing is MOST appropriate when a:

 = Penetration testing is most appropriate when a new system is about to go live, because it is a method of evaluating the security of a system by simulating an attack from a malicious source. Penetration testing can help to identify and exploit vulnerabilities, assess the impact and risk of a breach, and provide recommendations for remediation and improvement. Penetration testing can also help to validate the effectiveness of the security controls and policies implemented for the new system, and ensure compliance with relevant standards and regulations. Penetration testing is usually performed after the system has undergone other types of testing, such as functional, performance, and usability testing, and before the system is deployed to the production environment. Penetration testing is not as appropriate when a new system is being designed, because the system is still in the early stages of development and may not have all the features and functionalities implemented. Penetration testing at this stage may not provide a realistic or comprehensive assessment of the system’s security, and may cause delays or disruptions in the development process. Penetration testing is also not as appropriate when a security policy is being developed, because the policy is a high-level document that defines the goals, objectives, and principles of information security for the organization. Penetration testing is a technical and operational activity that tests the implementation and enforcement of the policy, not the policy itself. Penetration testing is also not as appropriate when a security incident has occurred, because the incident may have already compromised the system and caused damage or loss. Penetration testing at this stage may not be able to prevent or mitigate the incident, and may interfere with the incident response and recovery efforts. Penetration testing after an incident may be useful for forensic analysis and lessons learned, but it is not the primary or immediate response to an incident. References = CISM Review Manual, 16th Edition, ISACA, 2021, pages 229-230, 233-234.