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Withdrawn on May 14, 2024. Superseded by SP 800-171 Rev. 3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

3.5.1 Identify system users, processes acting on behalf of users, and devices.

Control Family: Identification and Authentication

Control Type: Basic

SPRS Value: 5

SPRS Supplemental Guidance: N/A

CMMC Level(s):

IA.L1-b.1.v
IA.L2-3.5.1

Top Ten Failed Requirement: No

Referenced in:

DFARS 252.204-7012

Derived From: NIST SP 800-53r4

  • IA-2

  • IA-3

  • IA-5

NIST Supplemental Guidance:

[SP 800-63-3]

Discussion:

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.

[SP 800-63-3] provides guidance on digital identities.

Upon assessment, assessors must determine if-

3.5.1[a] system users are identified.
3.5.1[b] processes acting on behalf of users are identified.
3.5.1[c] devices accessing the system are identified.

Assessors are instructed to-

Examine: [SELECT FROM: Identification and authentication policy; procedures addressing user identification and authentication; system security plan, system design documentation; system configuration settings and associated documentation; system audit logs and records; list of system accounts; other relevant documents or records].

Interview: [SELECT FROM: Personnel with system operations responsibilities; personnel with information security responsibilities; system or network administrators; personnel with account management responsibilities; system developers].

Test: [SELECT FROM: Organizational processes for uniquely identifying and authenticating users; mechanisms supporting or implementing identification and authentication capability].

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 requirement, IA.L2-3.5.1, provides a vetted and trusted identity that supports the access control mechanism required by AC.L2-3.1.1.

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 CUI, 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 Assessment 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]?