Mobile User Plane SIM Spoofing Checks via PFCP Proxy
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Solution Overview
Problem
SIM spoofing poses a significant security threat by allowing attackers to gain unauthorized access to sensitive information, as they can use a victim's phone number and SIM card to access accounts that rely on two-factor authentication.
Innovation Solution
Implementing a packet forwarding control protocol (PFCP) proxy within the network architecture to snoop messages and verify the validity of user equipment devices, using BGP controllers to generate and update session transformed routes, and perform reverse-path-forwarding checks to ensure that messages are validly generated by the intended user equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SIM spoofing is not prevented, then network simplicity is maintained, but security is compromised
Solution Approach 1:
The patent introduces a PFCP proxy as an intermediary component between the AMF and UPF in the 5G core network. This proxy acts as a mediator that intercepts, inspects, and validates PFCP messages to detect SIM spoofing attempts. By placing this intermediary at a specific point in the network architecture, the system achieves security enhancement without requiring complete redesign of the entire network, thus balancing security improvement with architectural complexity.
Solution Approach 2:
The patent implements preliminary validation actions by checking the IMSI field in PFCP messages before allowing data plane communication to proceed. The system performs reverse path forwarding checks and validates routing information in advance to prevent spoofed SIM cards from gaining access to the network. These preliminary security checks are performed during the session establishment phase, preventing potential security breaches before they can occur.
2Reliability
If packet inspection is performed to prevent SIM spoofing, then security is improved, but processing time increases
Solution Approach 1:
The patent applies local quality by performing security inspections only at specific critical points in the network architecture rather than throughout the entire data path. The PFCP proxy conducts packet inspection and SIM validation locally at the session establishment point, where the most critical security checks occur. This localized inspection approach ensures thorough security validation while minimizing the time impact on overall packet processing, as normal data traffic flows through without requiring repeated inspection.
Solution Approach 2:
The system implements feedback mechanisms where the PFCP proxy validates routing information and IMSI fields, then provides feedback decisions (allow/deny) to control the data plane session establishment. This feedback loop enables efficient security checking by immediately rejecting spoofed packets without requiring extensive processing, while allowing legitimate traffic to proceed through optimized paths.
3Difficulty of detecting and measuring
If reverse path forwarding checks are implemented, then spoofing detection is improved, but device complexity increases
Solution Approach 1:
The patent makes the PFCP proxy multi-functional by having it perform multiple tasks: forwarding PFCP messages between AMF and UPF, inspecting packet contents for security validation, checking routing information, and controlling session establishment. By consolidating these multiple functions into a single proxy component, the system achieves enhanced spoofing detection capabilities without proportionally increasing overall network complexity, as the proxy handles all these tasks through a unified architecture.
Data Source
AI summary
Prevention of SIM spoofing in mobile user plane. A method includes generating a border gateway protocol (BGP) flow specification based on a range of Internet Protocol (IP) addresses associated with routes for one or more user equipment devices. The method includes, in response to receiving a packet from a node within a radio access network, verifying an inner IP packet encapsulation based on the BGP flow specification.