NIST SP 800-171

**Executive summary:** This document provides an overview of NIST SP 800-171 (and related DFARS obligations) for DoD contractors, describing the 110 security requirements across 14 control families to protect Controlled Unclassified Information (CUI), highlighting critical areas (access control, audit, identification/authentication, incident response, risk and security assessment, system protection and integrity), and advising organizations—especially smaller contractors—to use qualified partners or managed security services to meet compliance obligations and avoid contract risk.