CM.L2-3.4.6
Least Functionality
Source and approval
CMMC Assessment Guide — Level 2 · Revision 2.13
Publisher approved · Complete cited source edition 2026-10-31
Read the official guideSee CM.L2-3.4.6 in the reference catalog with its NIST cross-references
Official requirement
Employ the principle of least functionality by configuring organizational systems to provide only essential capabilities.
Assessment objectives
a. essential system capabilities are defined based on the principle of least functionality; and
b. the system is configured to provide only the defined essential capabilities.
Implementation guidance
Editorial examples to help you plan. Adapt them to your environment; the official requirement and objectives remain authoritative.
In plain language
Configure systems to provide only the capabilities needed for their purpose.
Implementation example
Example from the source assessment guide (not a mandatory implementation): You have ordered a new server, which has arrived with a number of free utilities installed in addition to the operating system. Before you deploy the server, you research the utilities to determine which ones can be eliminated without impacting functionality. You remove the unneeded software, then move on to disable unused ports and services . The server that enters production therefore has only the essential capabilities enabled for the system to function in its role [a,b].
Evidence examples
Examples suggested by the source guide (not an exhaustive or mandatory checklist): 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
Common mistakes
Leaving default services and functions enabled without a business need.