DISCUSSION [NIST SP 800-171 R2]

Common device identifiers include media access control (MAC), Internet Protocol (IP) addresses, or device-unique token identifiers. Management of individual identifiers is not applicable to shared system accounts. Typically, individual identifiers are the user names associated with the system accounts assigned to those individuals. Organizations may require unique identification of individuals in group accounts or for detailed accountability of individual activity. In addition, this requirement addresses individual identifiers that are not necessarily associated with system accounts. Organizational devices requiring identification may be defined by type, by device, or by a combination of type/device. NIST SP 800-63-3 provides guidance on digital identities.

FURTHER DISCUSSION

Make sure to assign individual, unique identifiers (e.g., user names) to all users and processes that access company systems. Authorized devices also should have unique identifiers. Unique identifiers can be as simple as a short set of alphanumeric characters (e.g., SW001 could refer to a network switch, SW002 could refer to a different network switch).

This practice, IA.L1-3.5.1, provides a vetted and trusted identity that supports the access control mechanism required by AC.L1-3.1.1.

Example

You want to make sure that all employees working on a project can access important information about it. Because this is work for the DoD and may contain FCI, you also need to prevent employees who are not working on that project from being able to access the information. You assign each employee is assigned a unique user ID, which they use to log into the system [a].

Potential Considerations

Are unique identifiers issued to individual users (e.g., usernames) [a]?

Are the processes and service accounts that an authorized user initiates identified (e.g., scripts, automatic updates, configuration updates, vulnerability scans) [b]?

Are unique device identifiers used for devices that access the system identified [c]?

Copyright

Copyright 2020, 2021 Carnegie Mellon University and The Johns Hopkins University Applied Physics Laboratory LLC.

Copyright 2021 Futures, Inc.

This material is based upon work funded and supported by the Department of Defense under Contract No. FA8702-15-D-0002 with Carnegie Mellon University for the operation of the Software Engineering Institute, a federally funded research and development center, and under Contract No. HQ0034-13-D-0003 and Contract No. N00024-13-D-6400 with the Johns Hopkins University Applied Physics Laboratory LLC, a University Affiliated Research Center.

The view, opinions, and/or findings contained in this material are those of the author(s) and should not be construed as an official Government position, policy, or decision, unless designated by other documentation.

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