Level 1 only addresses the protection of Federal Contract Information (FCI) and does not include requirements for safeguarding Controlled Unclassified Information (CUI).

Level 2 is explicitly designed to protect Controlled Unclassified Information (CUI). It requires implementation of all 110 security requirements from NIST SP 800-171 Rev. 2, which directly support the safeguarding of CUI and help prevent its unauthorized disclosure or exfiltration.

Level 3 builds on Level 2 by including a subset of requirements from NIST SP 800-172. These additional practices are designed to enhance the protection of CUI against advanced persistent threats (APTs), further strengthening defenses against exfiltration.

Therefore, the levels that focus on protecting CUI from exfiltration are Levels 2 and 3.

Reference Documents:

CMMC Model v2.0 Overview (DoD, December 2021)

NIST SP 800-171 Rev. 2,Protecting Controlled Unclassified Information in Nonfederal Systems and Organizations

NIST SP 800-172,Enhanced Security Requirements for Protecting Controlled Unclassified Information