# NIST SP 800-53 Rev. 5 AC-4(28) — Linear Filter Pipelines - Source: https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ac-4-28-linear-filter-pipelines - 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) › AC — Access Control - Last updated: 2026-06-05 - Publisher: iCompaas, Inc. (https://www.icompaas.com) **NIST SP 800-53 Rev. 5**·Control `AC-4(28)`·critical·Component: **Access Control** ## What this control requires > When transferring information between different security domains, organizations must implement a linear content filter pipeline, enforced with both discretionary and mandatory access controls. This control supports the Governance capability within the Access Control family. > > — NIST SP 800-53 Rev. 5, Control AC-4(28) ### In plain English When transferring information between different security domains, organizations must implement a linear content filter pipeline, enforced with both discretionary and mandatory access controls. In practice, this means you can prove you access 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 **Access Control**, the assessor will trace your implementation back to the catalogue reference (Control AC-4(28)) 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. - **Mandatory.** Document the trigger, the owner and the cadence. - **Discretionary.** Document the trigger, the owner and the cadence. - **Information.** Document the trigger, the owner and the cadence. - **Security.** Document the trigger, the owner and the cadence. - **Scope:** management, access control, information, domains, filter pipelines, controls, identity, review. ## 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: Linear Filter Pipelines. ## 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 800-171 Rev. 3 3.1.11** — Session Termination](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-1-11-session-termination) - [**CIS Controls v8 6.7** — Centralize Access Control](https://support.icompaas.com/compliance/cis-controls-v8/6-7-centralize-access-control) - [**ISO/IEC 27001:2022 A.5.2** — Information security roles and responsibilities](https://support.icompaas.com/compliance/iso-27001-2022/a-5-2-information-security-roles-and-responsibilities) - [**SOC 2 (2017 TSC) CC6.1** — Logical Access Controls](https://support.icompaas.com/compliance/soc-2-trust-services-criteria/cc6-1-logical-access-controls) - [**BSI C5:2020 PS-04** — Physical site access control](https://support.icompaas.com/compliance/bsi-c5-2020/ps-04-physical-site-access-control) ## Related controls in NIST SP 800-53 Rev. 5 - [**Control AC-4(22)** — Access Only](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ac-4-22-access-only) - [**Control AC-3(8)** — Revocation Of Access Authorizations](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ac-3-8-revocation-of-access-authorizations) - [**Control AC-6(2)** — Non-Privileged Access For Nonsecurity Functions](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ac-6-2-non-privileged-access-for-nonsecurity-functions) - [**Control AC-14** — Permitted Actions Without Identification Or Authentication](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ac-14-permitted-actions-without-identification-or-authentication) - [**Control AC-3(2)** — Dual Authorization](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ac-3-2-dual-authorization) - [**Control AC-4(32)** — Process Requirements For Information Transfer](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ac-4-32-process-requirements-for-information-transfer) ## 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 AC-4(28)` Topics: identity accessidentity managementaccess reviewprivileged accessdevsecops ## 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.