| name | AC-4(27)_redundantindependent-filtering-mechanisms |
| description | When transferring information between different security domains, implement content filtering solutions that provide redundant and independent filteri |
| category | authorization |
| version | 5.2.0 |
| author | cyberstrike-official |
| tags | ["nist","sp800-53","rev5","ac-4-27","ac","enhancement"] |
| tech_stack | ["aws","azure","gcp","linux","windows"] |
| cwe_ids | ["CWE-284"] |
| chains_with | [] |
| prerequisites | ["AC-4"] |
| severity_boost | {} |
AC-4(27) Redundant/Independent Filtering Mechanisms
Enhancement of: AC-4
High-Level Description
Family: Access Control (AC)
Framework: NIST SP 800-53 Rev 5
Content filtering is the process of inspecting information as it traverses a cross-domain solution and determines if the information meets a predefined policy. Redundant and independent content filtering eliminates a single point of failure filtering system. Independence is defined as the implementation of a content filter that uses a different code base and supporting libraries (e.g., two JPEG filters using different vendors’ JPEG libraries) and multiple, independent system processes.
What to Check
How to Test
Step 1: Review Documentation
Examine the System Security Plan (SSP) and related artifacts for AC-4(27) implementation details. Verify the organization has documented how this control is satisfied.
Step 2: Validate Implementation
# For cloud environments, use cloud-audit-mcp tools
# For on-premises, review system configurations directly
# Example: Check if account management policies exist
grep -r "account.management\|access.control" /etc/security/ 2>/dev/null
Step 3: Test Operating Effectiveness
Verify the control is actively functioning, not just documented. Check logs, configurations, and operational evidence.
Tools
| Tool | Purpose | Usage |
|---|
| cloud-audit-mcp | Check IAM policies and access controls | cloud_audit_iam_policies |
| hackbrowser-mcp | Test web application access controls | browser_auth_test |
Remediation Guide
Control Statement
When transferring information between different security domains, implement content filtering solutions that provide redundant and independent filtering mechanisms for each data type.
Implementation Guidance
