Limit information system access to authorized users, processes acting on behalf of authorized users, or devices (including other information systems).
Source Discussion
Access control policies (e.g., identity- or role-based policies, control matrices, and cryptography) control access between active entities or subjects (i.e., users or processes acting on behalf of users) and passive entities or objects (e.g., devices, files, records, and domains) in systems.
Access enforcement mechanisms can be employed at the application and service level to provide increased information security. Other systems include systems internal and external to the organization.
This requirement focuses on account management for systems and applications. The definition of and enforcement of access authorizations, other than those determined by account type (e.g., privileged verses [sic] non-privileged) are addressed in requirement 3.1.2 (AC.1.002).
CMMC Clarification
Control who can use company computers and who can log on to the company network. Limit the services and devices, like printers, that can be accessed by company computers. Set up your system so that unauthorized users and devices cannot get on the company network.
CMMC GUIDE FURTHER DISCUSSION
Identify users, processes, and devices that are allowed to use company computers and can log on to the company network [a]. Automated updates and other automatic processes should be associated with the user who initiated (authorized) the process [b]. Limit the devices (e.g., printers) that can be accessed by company computers [c]. Set up your system so that only authorized users, processes, and devices can access the company network [d,e,f].
This practice, AC.1.001, controls system access based on user, process or device identity. AC.1.001 leverages IA.1.076, which provides a vetted and trusted identity for access control required by AC.1.001.
Examples
Example 1
You are in charge of IT for your company. You give a username and password to every employee who uses a company computer for their job. No one can use a company computer without a username and a password. You give a username and password only to those employees you know have permission to be on the system. When an employee leaves the company, you disable their username and password immediately.
Example 2
A coworker from the marketing department tells you their boss wants to buy a new multi- function printer/scanner/fax device and make it available on the company network. You explain that the company controls system and device access to the network, and will stop non-company systems and devices unless they already have permission to access the network. You work with the marketing department to grant permission to the new printer/scanner/fax device to connect to the network, then install it.
References
FAR Clause 52.204-21 b.1.i
NIST SP 800-171 Rev 1 3.1.1
CIS Controls v7.1 1.4, 1.6, 5.1, 14.6, 15.10, 16.8, 16.9, 16.11
NIST CSF v1.1 PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-3, PR.PT-4
CERT RMM v1.2 TM:SG4.SP1
NIST SP 800-53 Rev 4 AC-2, AC- 3, AC-17
AU ACSC Essential Eight
