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Withdrawn on May 14, 2024. Superseded by SP 800-171 Rev. 3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

SPRS Value: 1

SPRS Supplemental Guidance: N/A

CMMC Level(s): IA.L2-3.5.6

Top Ten Failed Requirement: No

Referenced in:

DFARS 252.204-7012

Derived From: NIST SP 800-53r4

  • IA-4

NIST Supplemental Guidance:

N/A

Discussion:

Inactive identifiers pose a risk to organizational information because attackers may exploit an inactive identifier to gain undetected access to organizational devices. The owners of the inactive accounts may not notice if unauthorized access to the account has been obtained.

Upon assessment, assessors must determine if-

3.5.6[a] a period of inactivity after which an identifier is disabled is defined.
3.5.6[b] identifiers are disabled after the defined period of inactivity.

Assessors are instructed to-

Examine: [SELECT FROM: Identification and authentication policy; procedures addressing identifier management; procedures addressing account management; system security plan; system design documentation; system configuration settings and associated documentation; list of system accounts; list of identifiers generated from physical access control devices; other relevant documents or records].

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

Test: [SELECT FROM: Mechanisms supporting or implementing identifier management].

FURTHER DISCUSSION

Identifiers are uniquely associated with an individual, account, process, or device. An inactive identifier is one that has not been used for a defined extended period of time. For example, a user account may be needed for a certain time to allow for transition of business processes to existing or new staff. Once use of the identifier is no longer necessary, it should be disabled as soon as possible. Failure to maintain awareness of accounts that are no longer needed yet still active could allow an adversary to exploit IT services.

Example

One of your responsibilities is to enforce your company’s inactive account policy: any account that has not been used in the last 45 days must be disabled [a]. You enforce this by writing a script that runs once a day to check the last login date for each account and generates a report of the accounts with no login records for the last 45 days. After reviewing the report, you notify each inactive employee’s supervisor and disable the account [b].

Potential Assessment Considerations

  • Are user accounts or identifiers monitored for inactivity [b]?