# NIST SP 800-171 Rev. 3 3.5.4 — Replay-Resistant Authentication - Source: https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-5-4-replay-resistant-authentication - Section: [Compliance](https://support.icompaas.com/compliance) › [NIST SP 800-171 Rev. 3 Requirements](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3) › Identification and Authentication — §3.5 - Last updated: 2026-06-05 - Publisher: iCompaas, Inc. (https://www.icompaas.com) **NIST SP 800-171 Rev. 3**·Requirement `3.5.4`·critical·Component: **Identification and Authentication** ## What this control requires > This control requires implementing replay-resistant authentication mechanisms for privileged and non-privileged accounts to prevent replay attacks. Techniques include using protocols with nonces or challenge-response methods, such as time-synchronous or one-time authenticators, to ensure that authentication messages cannot be recorded and reused by unauthorized parties. This control supports the Replay-Resistant Mechanism capability within the Identification and Authentication (3.5) family. > > — NIST SP 800-171 Rev. 3, Requirement 3.5.4 ### In plain English This control requires implementing replay-resistant authentication mechanisms for privileged and non-privileged accounts to prevent replay attacks. In practice, this means you can prove you access management-level controls on a defined cadence. ## Why it matters DoD contractors and their subcontractors must implement all 100 SP 800-171 requirements to keep CUI handling contracts. Gaps are scored against the SPRS scoring methodology; below a 110-point starting score, each unmet requirement deducts points and a below-threshold score can disqualify a bid. This control is rated **critical** in the source catalogue. Treat gaps here as production incidents in the risk register, not housekeeping. ## What an auditor looks for A C3PAO conducting a CMMC Level 2 assessment uses NIST SP 800-171A objectives. They expect a System Security Plan (SSP), Plan of Action & Milestones (POA&M) for any gaps, and objective evidence (configurations, ticket records, training records) for every requirement. Within **Identification and Authentication**, the assessor will trace your implementation back to the catalogue reference (Requirement 3.5.4) and look for objective evidence on the latest two assessment cycles. ## How to implement 1. Write a short policy stating intent, scope and named owner. 2. Encode it as a platform guardrail — SCP, Azure Policy initiative, Organisation Policy, or repository policy. 3. Wire a monitoring signal that catches drift (CSPM rule, SIEM rule, scheduled query, Workspace alert) and ticket it. 4. Review on a documented cadence and capture the review in the risk register or compliance tracker. ### Operational checklist - **Access.** Document the trigger, the owner and the cadence. - **Response.** Document the trigger, the owner and the cadence. - **Time.** Document the trigger, the owner and the cadence. - **Replay-Resistant.** Document the trigger, the owner and the cadence. - **Authentication.** Document the trigger, the owner and the cadence. - **Scope:** management, time, authentication, challenge response methods, time synchronous, one time authenticators. ## Evidence to collect - **Identity Scan.** IAM / IdP exports — Entra ID, Okta, IAM Identity Center, Workspace directory — showing accounts, roles, MFA state and last sign-in. Identity analytics (Okta, SailPoint, Access Analyzer) demonstrates least-privilege. Focus: Replay-Resistant Authentication. ## How it maps to other frameworks Computed from shared tags, control component and key-operation subjects — handy when you are reconciling controls across an audit. - [**NIST SP 800-53 Rev. 5 IA-2(8)** — Access To Accounts -- Replay Resistant](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ia-2-8-access-to-accounts-replay-resistant) - [**SOC 2 (2017 TSC) CC6.2** — Access Provisioning](https://support.icompaas.com/compliance/soc-2-trust-services-criteria/cc6-2-access-provisioning) - [**ISO/IEC 27001:2022 A.8.2** — Privileged access rights](https://support.icompaas.com/compliance/iso-27001-2022/a-8-2-privileged-access-rights) - [**CIS Controls v8 14.9** — Conduct Role-Specific Security Awareness and Skills Training](https://support.icompaas.com/compliance/cis-controls-v8/14-9-conduct-role-specific-security-awareness-and-skills-training) - [**BSI C5:2020 PSS-05** — Authentication Mechanisms](https://support.icompaas.com/compliance/bsi-c5-2020/pss-05-authentication-mechanisms) ## Related controls in NIST SP 800-171 Rev. 3 - [**Requirement 3.5.1** — User Identification and Authentication](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-5-1-user-identification-and-authentication) - [**Requirement 3.5.5** — Identifier Management](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-5-5-identifier-management) - [**Requirement 3.5.3** — Multi-Factor Authentication](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-5-3-multi-factor-authentication) - [**Requirement 3.5.7** — Password Management](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-5-7-password-management) - [**Requirement 3.1.8** — Unsuccessful Logon Attempts](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-1-8-unsuccessful-logon-attempts) - [**Requirement 3.7.5** — Nonlocal Maintenance](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-7-5-nonlocal-maintenance) ## References - [NIST Computer Security Resource Center — NIST SP 800-171 Rev. 3](https://csrc.nist.gov/pubs/sp/800/171/r3/final) - Catalogue identifier: `Requirement 3.5.4` Topics: identity accessprivileged accessidentity managementaccess review ## Related compliance guidance - [NIST SP 800-171 and CMMC: a practical guide to protecting CUI in the cloud](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3): Start with the full NIST SP 800-171 implementation guide — scope, roadmap, evidence and how the assessment runs. - [NIST SP 800-53 Rev. 5: a practical implementation guide for cloud teams](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5): The catalogue 800-171 is tailored from, and the basis of the FedRAMP Moderate baseline your cloud providers must meet for CUI. - [ISO/IEC 27001:2022 compliance: a practical implementation guide](https://support.icompaas.com/compliance/iso-27001-2022): If commercial customers ask for a certificate as well, most 800-171 controls can be evidenced once and mapped to Annex A.