AC-4(27)—Redundant/Independent Filtering Mechanisms
>Control Description
When transferring information between different security domains, implement content filtering solutions that provide redundant and independent filtering mechanisms for each data type.
>Supplemental 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.