When using a third party to perform penetration testing, the most important control to minimize operational impact is to clearly define the project scope. This means specifying the objectives,boundaries, methods, and deliverables of the testing, as well as the roles and responsibilities of the parties involved. A clear project scope helps to avoid misunderstandings, conflicts, and disruptions that could compromise the security, availability, or integrity of the systems undertest. It also helps to ensure that the testing is aligned with the organization’s risk appetite and compliance requirements. References = Risk and Information Systems Control Study Manual, 7th Edition, Chapter 3, Section 3.2.3.2, Page 137.