# NIST SP 800-171 Rev. 3 3.5.5 — Identifier Management - Source: https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-5-5-identifier-management - 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 `3.5.5`·high·Component: **Identification and Authentication** ## What this control requires > This control requires receiving authorization before assigning identifiers to individuals, groups, roles, services, or devices. It mandates preventing the reuse of identifiers for a defined period and managing individual identifiers by uniquely identifying each individual based on an organization-defined characteristic. This helps ensure accurate identification and communication within the organization. This control supports the Identifier Assignment System capability within the Identification and Authentication (3.5) family. > > — NIST SP 800-171 Rev. 3, Requirement 3.5.5 ### In plain English This control requires receiving authorization before assigning identifiers to individuals, groups, roles, services, or devices. 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 **high**. Auditors expect a named owner, a remediation SLA, and a tooling artefact that evidences continuous operation. ## 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 3.5.5) 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. - **System.** Document the trigger, the owner and the cadence. - **Identifier.** Document the trigger, the owner and the cadence. - **Authentication.** Document the trigger, the owner and the cadence. - **Scope:** management, authentication, individuals, authorization. ## 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: Identifier Management. ## 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-4** — Identifier Management](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ia-4-identifier-management) - [**ISO/IEC 27001:2022 A.8.23** — Web filtering](https://support.icompaas.com/compliance/iso-27001-2022/a-8-23-web-filtering) - [**SOC 2 (2017 TSC) CC1.5** — Accountability for Internal Control Responsibilities](https://support.icompaas.com/compliance/soc-2-trust-services-criteria/cc1-5-accountability-for-internal-control-responsibilities) - [**CIS Controls v8 9.2** — Use DNS Filtering Services](https://support.icompaas.com/compliance/cis-controls-v8/9-2-use-dns-filtering-services) - [**ISO/IEC 27701:2025 A.3.8** — Identity management](https://support.icompaas.com/compliance/iso-27701-2025/a-3-8-identity-management) ## Related controls in NIST SP 800-171 Rev. 3 - [**Requirement 3.5.7** — Password Management](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-5-7-password-management) - [**Requirement 3.9.1** — Personnel Screening](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-9-1-personnel-screening) - [**Requirement 3.5.12** — Authenticator Management](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-5-12-authenticator-management) - [**Requirement 3.7.5** — Nonlocal Maintenance](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-7-5-nonlocal-maintenance) - [**Requirement 3.13.14** — Technology-specific.](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-13-14-technology-specific) - [**Requirement 3.13.4** — Information in Shared System Resources](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-13-4-information-in-shared-system-resources) ## 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 3.5.5` Topics: identity accessidentity managementaccess reviewprivileged access ## 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.