NIST Special Publication 800-171 Revision 2
Date Published: January 28th, 2021
Withdrawn on May 14, 2024. Superseded by SP 800-171 Rev. 3
Author(s): Ron Ross (NIST), Victoria Pillitteri (NIST), Kelley Dempsey (NIST), Mark Riddle (NARA), Gary Guissanie (IDA)
Note: A Class Deviation is in effect as of May 2, 2024 (DEVIATION 2024O0013). The deviation clause requires contractors, who are subject to 252.204-7012, to comply with National Institute of Standards and Technology (NIST) Special Publication (SP) 800-171 Revision 2, instead of the version of NIST SP 800-171 in effect at the time the solicitation is issued or as authorized by the contracting officer. Click Here
AC-3.4.6 Employ the principle of least functionality by configuring organizational systems to provide only essential capabilities.
Control Family: Configuration Management
Control Type: Derived
SPRS Value: 5
SPRS Supplemental Guidance:
N/A
CMMC Level(s):
CM.L2-3.4.6
Top Ten Failed Requirement:
No
Referenced in:
DFARS 252.204-7012
Derived From: NIST SP 800-53r4
CM-7
NIST Supplemental Guidance:
N/A
Discussion:
Systems can provide a wide variety of functions and services. Some of the functions and services routinely provided by default, may not be necessary to support essential organizational missions, functions, or operations. It is sometimes convenient to provide multiple services from single system components. However, doing so increases risk over limiting the services provided by any one component. Where feasible, organizations limit component functionality to a single function per component.
Organizations review functions and services provided by systems or components of systems, to determine which functions and services are candidates for elimination. Organizations disable unused or unnecessary physical and logical ports and protocols to prevent unauthorized connection of devices, transfer of information, and tunneling. Organizations can utilize network scanning tools, intrusion detection and prevention systems, and end-point protections such as firewalls and host-based intrusion detection systems to identify and prevent the use of prohibited functions, ports, protocols, and services.
Upon assessment, assessors must determine if-
3.4.6[a] essential system capabilities are defined based on the principle of least
functionality.
3.4.6[b] the system is configured to provide only the defined essential capabilities
Assessors are instructed to-
Examine: [SELECT FROM: Configuration management policy; configuration management plan; procedures addressing least functionality in the system; system security plan; system design documentation; system configuration settings and associated documentation; security configuration checklists; other relevant documents or records].
Interview: [SELECT FROM: Personnel with security configuration management responsibilities; personnel with information security responsibilities; system or network administrators].
Test: [SELECT FROM: Organizational processes prohibiting or restricting functions, ports, protocols, or services; mechanisms implementing restrictions or prohibition of functions, ports, protocols, or services].