Bypass Detection in Mobile Networks Using Real User Numbers

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Solution Overview

Problem

Current methods for detecting bypasses in mobile telephone networks are ineffective against fraudsters who intercept and terminate calls only to numbers on a 'Whitelist', as they avoid detection during test calls.

Innovation Solution

A method that involves creating a list of target numbers corresponding to real users, selected randomly or based on call history, and sending test calls to these numbers to detect bypasses, with the option to configure temporary call forwarding or silence to avoid disturbing users and using a 'phantom' application to manage test calls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If test calls are sent to dedicated test numbers, then the detection system can identify bypasses, but fraudsters can avoid detection by maintaining a whitelist of known test numbers

Engineering Contradiction:
Improvebypass detection reliabilityVSAvoidfraud detection coverage
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

Instead of using dedicated test numbers that fraudsters can identify and whitelist, the system inverts the approach by using real user numbers as test targets. This makes it impossible for fraudsters to anticipate which numbers will be tested, thereby eliminating the whitelist defense mechanism while maintaining detection reliability

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The system performs preliminary selection of target numbers from the operator's database of real user numbers before conducting tests. By pre-selecting from a large pool of legitimate numbers, the system ensures that fraudsters cannot predict which numbers will be targeted, thus preventing whitelist-based evasion

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If test calls are sent to real user numbers, then the detection coverage is improved, but users may be disturbed by receiving test calls

Engineering Contradiction:
Improvedetection coverageVSAvoiduser disturbance
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system introduces an intermediary mechanism in the form of call forwarding configuration. Before sending a test call, the system temporarily forwards the real user's calls to a monitoring number, allowing test calls to be conducted without disturbing the user. After testing, the forwarding is removed, restoring normal service

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary configuration of call forwarding or silence settings before sending test calls to real user numbers. This preliminary action ensures that users are not disturbed by incoming test calls, while still allowing the detection system to function effectively

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If a large number of test calls are sent to verify number legitimacy, then false positives are reduced, but the time and resources required increase

Engineering Contradiction:
Improvenumber legitimacy verification accuracyVSAvoidverification time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system changes the parameters used for verifying number legitimacy by analyzing multiple attributes of call history (frequency, duration, time patterns, destination numbers) rather than relying on a single criterion. This multi-parameter approach improves verification accuracy while allowing for efficient filtering of obviously legitimate numbers, reducing the overall time required

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3472999B1Method and system for detecting bypass in a mobile telephonie network
Publication Date: 2022.01.26 ARAXXE
  • EP3472999B1 patent drawingFigure 1
  • EP3472999B1 patent drawingFigure 2
  • EP3472999B1 patent drawingFigure 3

AI summary

The invention relates to a method (100) for detecting bypasses in a mobile telephone network, comprising at least one iteration of a test phase (112) comprising the following steps: - sending (116) of at least one test call, to at least one call number, termed the target number, - for at least one test call: - storage (116) of a caller identifier, termed sending caller identifier, used when sending, - recovery of a caller identifier, termed caller reception identifier, received for said test call, and - comparison (120) of said sending and reception caller identifiers; characterized in that it comprises a phase (102) of constructing a list of target numbers by selecting call numbers corresponding to real users. The invention also relates to a system for implementing said method.