5G NAS Signaling Validation Against Spurious Information Elements
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Solution Overview
Problem
The handling of non-access stratum (NAS) signaling in 5G networks is challenged by spurious information elements (IEs) in NAS messages, leading to processing delays and security risks, particularly in emergency services scenarios.
Innovation Solution
Implement procedures for robust handling of NAS messages by ensuring that the type of the child NAS message matches the parent message, ignoring or discarding spurious IEs, and sending error messages when mismatches occur, thereby preventing malicious attacks and reducing processing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the AMF processes all IEs in NAS messages without validation, then processing completeness is maintained, but processing delays increase and security risks arise from spurious IEs
Solution Approach 1:
The patent applies preliminary action by validating the procedure type of child NAS messages against parent message types before processing. The AMF checks whether the procedure type in the NAS message container matches the expected type based on the parent message, and only processes the child message if the types are compatible. This preliminary validation prevents processing delays and security issues caused by spurious IEs while maintaining efficient processing of valid messages.
2Reliability
If the AMF validates procedure types of child NAS messages, then security against spurious IEs is improved, but message processing complexity increases
Solution Approach 1:
The patent applies parameter changes by introducing a procedure type parameter check. The AMF extracts the procedure type parameter from the parent NAS message and compares it with the procedure type parameter in the child NAS message contained in the NAS message container. This simple parameter validation approach provides security against spurious IEs without requiring complex validation logic, thus maintaining low processing complexity while improving security.
3Productivity
If spurious IEs are ignored or discarded, then processing efficiency is improved, but information loss may occur if valid IEs are mistakenly discarded
Solution Approach 1:
The patent applies local quality by selectively processing different parts of the NAS message based on their validity. The AMF performs local validation on the procedure type parameter of the child NAS message and applies different processing actions locally: if the procedure types are compatible, the child message is processed normally; if they are incompatible, only the spurious child message is discarded while the parent message and other valid IEs continue to be processed. This localized validation approach improves processing efficiency by discarding only invalid elements without causing information loss of valid elements.
Data Source
AI summary
Procedures are provided for robust handling of NAS request messages that contain a spurious information element (IE). The spurious information element could include a NAS message container containing a NAS message with the wrong procedure type, i.e., a procedure type that does not match the type of the parent NAS message. The spurious information elements could also include redundant IEs that are not necessary for the emergency services fallback request.