CMMC Practice MA.2.114
Supervise the maintenance activities of personnel without required access authorization.
Bold Coast Security Guidance
For Level 1 compliance there must be a practice in place to escort maintenance personnel who do not have authorized access to secure or sensitive facilities and equipment. For Level 2, there must be a policy requiring that supervision. This policy may also contain the requirement for a visitor's log that is maintained.
DRAFT NIST SP 800-171 R2
This requirement applies to individuals who are performing hardware or software maintenance on organizational systems, while PE.1.131 addresses physical access for individuals whose maintenance duties place them within the physical protection perimeter of the systems (e.g., custodial staff, physical plant maintenance personnel) . Individuals not previously identified as authorized maintenance personnel, such as information technology manufacturers, vendors, consultants, and systems integrators, may require privileged access to organizational systems, for example, when required to conduct maintenance activities with little or no notice. Organizations may choose to issue temporary credentials to these individuals based on organizational risk assessments . Temporary credentials may be for one-time use or for very limited time periods.