The purpose of this memorandum is to notify you that we plan to begin the subject audit in September 2023. This audit is the first in a planned series of audits that addresses the DoD’s ability to protect Defense Critical Infrastructure against cyber vulnerabilities. The objective of this audit is to assess the progress made by the Departments of the Navy and Air Force in mitigating the Defense Critical Infrastructure cybersecurity vulnerabilities identified during the installation evaluations conducted in response to section 1650 of the National Defense Authorization Act for FY 2017.