3.1.2
AC.L1-3.1.2 · Level 1 + 2
Limit system access to the types of transactions and functions that authorized users are permitted…
NIST SP 800-171 Rev 2 · §3.1.2
Limit system access to the types of transactions and functions that authorized users are permitted to execute.
Assessment objectives
From NIST SP 800-171A · 2 objectives must be met to satisfy this control
Examine
[SELECT FROM: Access control policy; procedures addressing access enforcement; security plan; system design documentation; list of approved authorizations (user privileges) including remote access authorizations; system configuration settings and associated documentation; system audit logs and records; other relevant documents or records].
Interview
[SELECT FROM: Personnel with access enforcement responsibilities; system or network administrators; personnel with information security responsibilities; system developers].
Test
[SELECT FROM: Mechanisms implementing access control policy].
Examine
[SELECT FROM: Access control policy; procedures addressing access enforcement; security plan; system design documentation; list of approved authorizations (user privileges) including remote access authorizations; system configuration settings and associated documentation; system audit logs and records; other relevant documents or records].
Interview
[SELECT FROM: Personnel with access enforcement responsibilities; system or network administrators; personnel with information security responsibilities; system developers].
Test
[SELECT FROM: Mechanisms implementing access control policy].
What we look for in practice
The following are placeholder notes that should be refined based on practice experience.
What assessors look for in practice. Documented evidence that this control is implemented across all CUI-handling systems within scope. Specific artifacts vary, but expect requests for written procedures, system configurations, and operational records demonstrating the control is active.
Common failure patterns. Typical issues include incomplete documentation, inconsistent implementation across systems, and missing periodic review records. Refine this section as your practice accumulates direct assessment experience.
Strong evidence looks like. Formal policy referencing this control, technical configurations demonstrating enforcement, periodic review logs with sign-off, and procedures for handling exceptions.
Scoring and POA&M context. 5-point control under the DoD Assessment Methodology. Highest scoring impact — treat as a foundational requirement. Not POA&M-eligible — must be implemented at assessment time.