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Controls / Identification and Authentication / 3.5.4
3.5.4
IA.L2-3.5.4 · Level 2

Employ replay-resistant authentication mechanisms for network access to privileged and…

NIST SP 800-171 Rev 2 · §3.5.4

Employ replay-resistant authentication mechanisms for network access to privileged and non-privileged accounts.

Assessment objectives

From NIST SP 800-171A · 1 objective must be met to satisfy this control
3.5.4[a] Employ replay-resistant authentication mechanisms for network access to privileged and non-privileged accounts.
Examine
[SELECT FROM: Identification and authentication policy; procedures addressing user identification and authentication; security plan; system design documentation; system configuration settings and associated documentation; system audit logs and records; list of privileged system accounts; other relevant documents or records].
Interview
[SELECT FROM: Personnel with system operations responsibilities; personnel with account management responsibilities; personnel with information security responsibilities; system or network administrators; system developers].
Test
[SELECT FROM: Mechanisms supporting or implementing identification and authentication capability or replay resistant authentication mechanisms].

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. 1-point control under the DoD Assessment Methodology. Lower scoring impact, but still required for full compliance. POA&M-eligible — deferral up to 180 days is allowed under conditional certification per 32 CFR 170.21.