# NIST SP 800-53 Rev. 5 SC-23(3) — Unique System-Generated Session Identifiers - Source: https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/sc-23-3-unique-system-generated-session-identifiers - Section: [Compliance](https://support.icompaas.com/compliance) › [NIST SP 800-53 Rev. 5 Controls](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5) › SC — System and Communications Protection - Last updated: 2026-06-05 - Publisher: iCompaas, Inc. (https://www.icompaas.com) **NIST SP 800-53 Rev. 5**·Control `SC-23(3)`·critical·Component: **System and Communications Protection** ## What this control requires > Generate a unique session identifier for each session with organization-defined randomness requirements and recognize only system-generated session identifiers. This approach prevents adversaries from reusing valid session IDs and protects against brute-force attacks aimed at predicting future session identifiers. This control supports the Session Identifier Generation System capability within the System and Communications Protection family. > > — NIST SP 800-53 Rev. 5, Control SC-23(3) ### In plain English Generate a unique session identifier for each session with organization-defined randomness requirements and recognize only system-generated session identifiers. In practice, this means you can prove you policy management-level controls on a defined cadence. ## Why it matters SP 800-53 is the catalogue every U.S. federal authorisation (FedRAMP, FISMA, CMMC) and most regulated industries point at. A missing control surfaces as a Plan of Action & Milestones (POA&M) item that an Authorizing Official must approve before the Authority To Operate is granted or renewed. 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 3PAO (FedRAMP) or Independent Assessor (NIST RMF) tests against NIST SP 800-53A assessment procedures. For each control they expect a documented implementation that addresses every assessment objective (Examine, Interview, Test) and an implementation summary in the System Security Plan. Within **System and Communications Protection**, the assessor will trace your implementation back to the catalogue reference (Control SC-23(3)) and look for objective evidence on the latest two assessment cycles. ## How to implement #### Policy Management **Docs.** Keep each policy in version-controlled Markdown alongside the code that implements it; ship a signed PDF snapshot at each annual review and link the SHA into the SoA. ### Operational checklist - **Policy.** Document the trigger, the owner and the cadence. - **Session.** Document the trigger, the owner and the cadence. - **Protection.** Document the trigger, the owner and the cadence. - **System.** Document the trigger, the owner and the cadence. - **Control.** Document the trigger, the owner and the cadence. - **Scope:** management, organization, system, only, protection, generation, capability, policy. ## Evidence to collect - **Policy Document.** A signed and version-controlled policy / standard / procedure document. Signed policy or standard documents the safeguard. Focus: Unique System-Generated Session Identifiers. ## Common pitfalls - Policies that no engineer has read; the version in Confluence drifts from the version that's actually being enforced. ## 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. - [**HIPAA (45 CFR Part 164) 164.502(j)(2)** — Disclosures by workforce members who are victims of a crime](https://support.icompaas.com/compliance/hipaa/164-502-j-2-disclosures-by-workforce-members-who-are-victims-of-a-crime) - [**NIST SP 800-171 Rev. 3 3.14.3** — Security Alerts, Advisories, and Directives](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-14-3-security-alerts-advisories-and-directives) - [**ISO/IEC 27001:2022 A.8.26** — Application security requirements](https://support.icompaas.com/compliance/iso-27001-2022/a-8-26-application-security-requirements) - [**BSI C5:2020 SP-01** — Documentation, communication and provision of policies and instructions](https://support.icompaas.com/compliance/bsi-c5-2020/sp-01-documentation-communication-and-provision-of-policies-and-instructions) ## Related controls in NIST SP 800-53 Rev. 5 - [**Control SC-15(4)** — Explicitly Indicate Current Participants](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/sc-15-4-explicitly-indicate-current-participants) - [**Control SC-6** — Resource Availability](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/sc-6-resource-availability) - [**Control SC-39(2)** — Separate Execution Domain Per Thread](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/sc-39-2-separate-execution-domain-per-thread) - [**Control SC-12(2)** — Symmetric Keys](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/sc-12-2-symmetric-keys) - [**Control SC-7(20)** — Dynamic Isolation And Segregation](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/sc-7-20-dynamic-isolation-and-segregation) - [**Control SC-13** — Cryptographic Protection](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/sc-13-cryptographic-protection) ## References - [NIST Computer Security Resource Center — NIST SP 800-53 Rev. 5](https://csrc.nist.gov/Projects/risk-management/sp800-53-controls) - Catalogue identifier: `Control SC-23(3)` Topics: governance riskpolicy management ## Related compliance guidance - [NIST SP 800-53 Rev. 5: a practical implementation guide for cloud teams](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5): Start with the full NIST SP 800-53 implementation guide — scope, roadmap, evidence and how the assessment runs. - [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): If your obligation is protecting CUI in your own systems for a federal or defence contract, this derived subset — not the full catalogue — is the requirement. - [SOC 2 compliance: a practical implementation guide for cloud-native SaaS teams](https://support.icompaas.com/compliance/soc-2-trust-services-criteria): Most commercial SaaS already hold a SOC 2 Type 2, and FedRAMP 20x Class A is designed for providers that have one.