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id: "AC-04(27)" title: "Redundant/Independent Filtering Mechanisms" family: "AC" family_name: "Access Control" sort_id: "ac-04.27" priority: "P1" implementation_level: "system" parent: "AC-04" enhancement: True

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Statement

When transferring information between different security domains, implement content filtering solutions that provide redundant and independent filtering mechanisms for each data type.

Guidance

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.

Assessment Objective

when transferring information between security domains, implemented content filtering solutions provide redundant and independent filtering mechanisms for each data type.

Information flow enforcement policy

procedures addressing information flow enforcement

system design documentation

system configuration settings and associated documentation

system audit records

system security plan

other relevant documents or records

Organizational personnel with information flow enforcement responsibilities

system/network administrators

organizational personnel with information security responsibilities

Mechanisms implementing information flow enforcement functions