SIP Server Spoof Detection via PLMN Registration Comparison

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Solution Overview

Problem

Mobile devices are susceptible to spoof communications, where ill-intentioned individuals impersonate known phone numbers, making it difficult for legitimate subscribers to trust the identity of incoming voice communications.

Innovation Solution

A spoof mitigation module within a SIP server is used to detect and verify the origin network of incoming VoIP communication requests by comparing the Public Land Mobile Network (PLMN) from recent registration data with the network identified in the SIP INVITE message, generating a spoof-likelihood score based on temporal indicators to determine the reliability of the call request.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional telecommunication networks allow incoming calls without verification, then call connectivity is maintained, but susceptibility to spoof communications increases

Engineering Contradiction:

Improveidentity verification reliabilityVSAvoidspoof communication susceptibility

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary verification of the originating device's identity by comparing the PLMN from registration data with the PLMN from the incoming call request before allowing the call to connect. This advance verification prevents spoofed calls from reaching the recipient while maintaining connectivity for legitimate calls.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The network server acts as an intermediary between the originating device and the recipient device, intercepting incoming call requests and verifying the originating device's identity against registered information. This intermediary verification process filters out spoofed calls while allowing legitimate calls to pass through to the recipient.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the network verifies every incoming call request, then spoof communication detection improves, but network processing complexity increases

Engineering Contradiction:

Improvespoof detection accuracyVSAvoidverification system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses a copy of the originating device's registered information (PLMN from registration data) and compares it with the PLMN from the incoming call request. This copying and comparison approach provides accurate spoof detection without requiring complex verification procedures, as it simply matches two pieces of information.

Inventive Principle:

Principle #26Copying

3Reliability

If legitimate calls are verified against registration data, then spoof call mitigation improves, but call setup time increases

Engineering Contradiction:

Improvecall authenticity verificationVSAvoidcall setup time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The originating device's registration information (including PLMN) is stored in advance in the network's registration data before any call is made. This preliminary storage allows the network to perform rapid verification by simply comparing the stored PLMN with the PLMN from the incoming call request, minimizing additional verification time.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11223955B2Mitigation of spoof communications within a telecommunications network

Publication Date: 2022.01.11 T MOBILE US INC

AI summary

The present disclosure describes techniques for detecting and mitigating a spoof communication within a network, such as a Session Internet Protocol (SIP) network. More specifically, a SIP server, may receive a call request to initiate a Voice over Internet Protocol (VoIP) communication between an originating device and a recipient device. In response, the SIP server may analyze registration data associated with a subscriber account of the originating device, and in doing so, infer whether the call request is a spoof communication.