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NIST SP 800-172 (Final Public Draft)

Enhanced Security Requirements for Protecting Controlled Unclassified Information: A Supplement to NIST Special Publication 800-171

Date Published: July 2020
Comments Due: August 21, 2020 (public comment period is CLOSED)
Email Questions to:

Planning Note (07/06/2020): We encourage reviewers to use the comment template for organizing and submitting comments.


Ron Ross (NIST), Victoria Pillitteri (NIST), Gary Guissanie (IDA), Ryan Wagner (IDA), Richard Graubart (MITRE), Deborah Bodeau (MITRE)


Draft NIST Special Publication (SP) 800-172 (formerly Draft NIST SP 800-171B) provides an enhanced security requirements to help protect the confidentiality, integrity, and availability of Controlled Unclassified Information (CUI) associated with critical programs or high value assets in nonfederal systems and organizations from the advanced persistent threat (APT). The APT is an adversary that possesses sophisticated levels of expertise and significant resources that allow it to create opportunities to achieve its objectives by using both cyber and physical attack vectors. The objectives include establishing and extending footholds within the infrastructure of the targeted organizations for the purposes of exfiltrating information; undermining or impeding critical aspects of a mission, program, or organization; or positioning itself to carry out these objectives in the future. The APT pursues its objectives repeatedly over an extended period, adapts to defenders’ efforts to resist it, and is determined to maintain the level of interaction needed to execute its objectives.

The enhanced security requirements provide the foundation for a new multidimensional, defense-in-depth protection strategy through (1) penetration-resistant architecture, (2) damage-limiting operations, and (3) designing for cyber resiliency and survivability that support and reinforce one another while providing resiliency against the APT.  This strategy recognizes that despite the best protection measures implemented by organizations, the APT may find ways to breach those primary boundary defenses and deploy malicious code within a defender’s system. When this situation occurs, organizations must have access to additional safeguards and countermeasures to outmaneuver, confuse, deceive, mislead, and impede the adversary—that is, take away the adversary’s tactical advantage and protect and preserve the organization’s critical programs and high value assets.

The enhanced security requirements, as identified and selected by a federal agency, can be implemented in addition to the basic and derived requirements in NIST SP 800-171 since those requirements are not designed to fully address high-end threats such as the APT. The enhanced security requirements apply only to the components of nonfederal systems that process, store, or transmit CUI or that provide protection for such components when the designated CUI is associated with a critical program or high value asset.

Based on feedback received during the public comment period, the final draft of this publication includes:

  • Updated scoping and applicability guidance;
  • A more flexible requirements selection approach to allow implementing organizations to customize their security solutions.
  • The addition of assignment and selection statements to certain requirements to give organizations the flexibility to establish specific parameter values, where appropriate.
  • The addition of adversary threat effects to show how each enhanced security requirement can influence the cyber attack chain.

Your feedback on this draft publication is important to us. We appreciate each contribution from our reviewers. The very insightful comments from both the public and private sectors, nationally and internationally, continue to help shape the final publication to ensure that it meets the needs and expectations of our customers.

The public comment period for this draft is open through August 21, 2020. We encourage reviewers to use the comment template for organizing and submitting comments.

NOTE: A call for patent claims is included on page v of this draft. For additional information, see the Information Technology Laboratory (ITL) Patent Policy--Inclusion of Patents in ITL Publications.



Advanced Persistent Threat; basic security requirement; contractor systems; Controlled Unclassified Information; CUI Registry; derived security requirement; enhanced security requirement; Executive Order 13556; FIPS Publication 199; FIPS Publication 200; FISMA; NIST Special Publication 800-53; nonfederal organizations; nonfederal systems; security assessment; security control; security requirement
Control Families

None selected


Download URL

Supplemental Material:
Comment template (xlsx)

Related NIST Publications:
SP 800-171 Rev. 2

Document History:
06/19/19: SP 800-171B (Draft)
07/06/20: SP 800-172 (Draft)
02/02/21: SP 800-172 (Final)