AC-4(14) - Information Flow Enforcement | Security or Privacy Policy Filter Constraints

When transferring information between different security domains, implement [Assignment: organization-defined security or privacy policy filters] requiring fully enumerated formats that restrict data structure and content.


ID: AC-4(14)
Enhancement of : AC-4

Space Segment Guidance

Strict filtering of data fields is crucial when multiple payloads or external systems interface with the spacecraft bus. Enumerating every permissible data format in the Interface Control Document (ICD) and enforcing these constraints on board can thwart fuzzing-like attacks or accidental misuse of mission-critical memory structures. For example, if a remote payload is expected to provide only eight bytes of sensor data, the space platform software should discard or flag anything beyond that specification. This "security or privacy policy filter" ensures that ill-formed, out-of-range, or malicious data never affects bus operations or other sensitive modules. The result is a more resilient integration of disparate systems, reducing unexpected cross-interactions or resource conflicts—mainly if the vehicle is part of a larger multi-organization or coalition environment.