What process involves an independent audit to review the information system and associated documentation to ensure necessary controls are implemented, as outlined in NIST SP 800-53?

The process that involves an independent audit to review the information system and associated documentation to ensure that the necessary controls are implemented, as outlined in NIST SP 800-53, is certification. Certification is a systematic evaluation of the security controls of an information system to determine their effectiveness in protecting the system and ensuring it meets specified requirements. This process is critical for establishing that a system is secure before it can be authorized for operation.

The certification process includes thorough documentation, testing, and other assessment activities to verify that the implemented security controls are functioning as intended. This aligns with the guidelines set forth in NIST SP 800-53, which provides a catalog of security and privacy controls for federal information systems and organizations.

While the other options are related to the overall security authorization process, they do not specifically refer to the independent audit evaluation of the controls. Authorization to Operate (ATO) refers to the formal approval to operate the system after certification is complete, whereas accreditation serves as the official management decision based on the certification results. The Plan of Actions and Milestones (POAM) outlines a plan for addressing weaknesses or deficiencies found during the assessment but is not the process of evaluating control effectiveness itself.