CAN Bus Malicious Hardware Detection via Impedance Analysis

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Solution Overview

Problem

Existing systems for detecting malicious hardware on vehicle data communication networks, such as CAN bus, face interference issues when injecting signals, leading to distortions and potential errors, and lack effective methods to distinguish between authorized and unauthorized connections.

Innovation Solution

The system employs impedance measurement using AC or DC signals across a range of frequencies, including during Deep Sleep Mode, and incorporates statistical analysis with machine learning techniques to differentiate between legitimate and malicious units, minimizing interference with vehicle systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If signals are injected onto the CAN bus for detection purposes, then detection capability is improved, but signal interference and ECU distortion occur

Engineering Contradiction:
Improvedetection capabilityVSAvoidsignal interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system performs impedance measurements periodically during Deep Sleep Mode intervals when no CAN communication is occurring, rather than continuously injecting signals. This periodic measurement approach enables detection functionality while avoiding continuous interference with ECU operations.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system utilizes the existing Deep Sleep Mode intervals of the vehicle network as natural measurement opportunities, rather than requiring separate dedicated measurement time slots. This self-service approach leverages the vehicle's own operational cycles to perform security detections without additional interference.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If impedance measurements are performed during active communication, then detection accuracy is improved, but communication errors and system disruptions occur

Engineering Contradiction:
Improvedetection accuracyVSAvoidcommunication reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system schedules impedance measurements to occur periodically during Deep Sleep Mode when the CAN bus is inactive, ensuring that measurements are performed without disrupting active communication. This timing strategy maintains both detection accuracy and communication reliability.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system performs impedance measurements in advance during Deep Sleep Mode intervals before normal communication resumes, allowing detection to occur proactively without interfering with subsequent communication operations.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If signal injection frequency is increased for faster detection, then detection speed is improved, but interference with vehicle systems increases

Engineering Contradiction:
Improvedetection speedVSAvoidinterference with vehicle systems
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system performs measurements during naturally occurring Deep Sleep Mode intervals, achieving detection without requiring high-frequency signal injection that would interfere with vehicle systems. The periodic nature of these intervals provides adequate detection speed while avoiding interference.

Inventive Principle:
Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for reliable detection of malicious hardware without disrupting vehicle operations, providing accurate differentiation and alerting mechanisms for potential threats.

Implementation Method 1

an AC signal generating device (140) configured to generate AC electrical current

Methodology Applied
Scientific EffectAC signal generation:

Implementation Method 2

an impedance measuring device (142) configured to measure the network bus impedance for each frequency

Methodology Applied
Scientific EffectImpedance measurement: Electrical Resistance

Data Source

PatentUS11068590B2System and processes for detecting malicious hardware
Publication Date: 2021.07.20 ENIGMATOS LTD
  • US11068590B2 patent drawing
  • US11068590B2 patent drawing
  • US11068590B2 patent drawing

AI summary

A system for detecting malicious hardware on a data communication network, such as a vehicle CAN bus, is provided. The system includes a teleprocessing device, an AC signal generating device, and an impedance measuring device. In a preliminary step, a set of impedance measurements of N reference AC signals is formed, and a threshold value is set. The signal generating device injects a set of N AC signals into the network bus and the bus impedance for each of the N frequencies is measured, where a set of impedance values of N RT-signals is formed. Then, each of the impedance values of the RT-signals and the impedance values of the respective reference AC signal are statistically compared, to thereby form a set of N comparison-results. Upon determining that any of the impedance values of the RT-signals is greater than the threshold, an alert is activated.