PnP Driver Security for Enumerated Bus Devices

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Solution Overview

Problem

Current techniques for detecting and preventing security exploits delivered through enumerated bus devices, such as USB devices, are limited, especially when device serial numbers are unknown or unavailable, posing significant threats like cyber terrorism and industrial espionage.

Innovation Solution

A Plug-and-Play (PnP) driver is developed to attach to device stacks of enumerated bus devices as upper or lower filters, allowing for the alteration, limitation, or blocking of device functionality, and creating unique descriptors for identification, while also inventorying and fingerprinting devices to enhance security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If device serial numbers are used to detect and block malicious USB devices, then security detection capability is improved, but the system becomes ineffective when serial numbers are unknown or unavailable

Engineering Contradiction:
Improvesecurity detection capabilityVSAvoideffectiveness against unknown devices
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a virtual copy of the USB device through a virtual device driver that mimics the physical device's behavior and interface. This virtual representation allows the security system to interact with and control the device without relying on physical serial numbers, enabling detection and blocking capabilities even when serial numbers are unavailable.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The virtual device driver acts as an intermediary layer between the operating system and the physical USB device. It intercepts and filters device communications, allowing the system to detect malicious devices through their operational characteristics rather than relying solely on serial number matching.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a PnP driver attaches to device stacks as filter to block malicious devices, then security protection is improved, but device complexity and potential false positives increase

Engineering Contradiction:
Improvesecurity protectionVSAvoiddriver architecture complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The virtual device driver serves as a controlled intermediary that attaches to device stacks only when needed for security detection. It provides a standardized interface for security operations without requiring complex modifications to the existing device stack architecture, thereby limiting the increase in system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If comprehensive device fingerprinting and inventorying is performed, then security monitoring capability is improved, but processing time and system resources increase

Engineering Contradiction:
Improvesecurity monitoring capabilityVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs device fingerprinting and inventorying activities in advance, during device enumeration and initialization phases. By completing these resource-intensive operations before normal device operation begins, the system minimizes the impact on processing time during active security monitoring.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Once devices are fingerprinted and inventoried initially, the system maintains continuous security monitoring using the collected information. This allows the system to leverage preliminary analysis results for ongoing security decisions, reducing the need for repeated comprehensive scanning and minimizing continuous processing overhead.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3514716B1Security component for devices on an enumerated bus
Publication Date: 2025.01.08 CROWDSTRIKE
  • EP3514716B1 patent drawingFigure 1
  • EP3514716B1 patent drawingFigure 2
  • EP3514716B1 patent drawingFigure 3

AI summary

A plug-and-play (PnP) driver associated with a security agent is described herein. The PnP driver attaches to device stacks of enumerated bus devices of a computing device as upper-device or lower-device filters based on the device classes of the enumerated bus devices. For example, the PnP driver may attach to the device stack of a hub or controller device as an upper-device filter and to device stacks of other devices as lower-device filters. Either while attaching or after attachment, the PnP driver may take action to alter, limit, or otherwise block functionality of an enumerated bus device. The PnP driver may also perform a system inventory of enumerated bus devices connected to the computing device and create fingerprints for one or more of the computing devices. Additionally, the PnP driver may create and remove control device objects (CDOs) to enable communication with user-mode processes or threads.