Spoofed Probe Response with NAV to Block Unauthorized APs

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Solution Overview

Problem

Unauthorized access points in wireless networks can compromise security by allowing unauthorized data transfers and bandwidth theft, as wireless devices may unknowingly connect to them, and these access points often lack the policies and procedures enforced by network administrators.

Innovation Solution

Deploying idle transceivers of MIMO transceiver chains to rapidly connect Wi-Fi clients, where MAC addresses of unauthorized access points are stored, and a spoofed probe response is transmitted with a high NAV value to prevent connections, allowing the wireless station to associate with an authorized access point instead.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If wireless devices connect to unauthorized access points, then connection availability is improved, but network security deteriorates

Engineering Contradiction:

Improveconnection availabilityVSAvoidnetwork security

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The authorized access point sends a spoofed probe response with a high NAV value before the wireless device can complete association with the unauthorized access point. This preliminary action blocks the connection attempt in advance, preventing the security breach before it occurs while still allowing the device to eventually connect to the authorized access point.

Inventive Principle:

Principle #9Preliminary anti-action

2Area of stationary object

If unauthorized access points are allowed, then network coverage is improved, but data security deteriorates

Engineering Contradiction:

Improvenetwork coverageVSAvoiddata security

Core Design Contradiction:

Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful presence of unauthorized access points into a benefit by using them as bait. The unauthorized access point attracts wireless devices, and the authorized access point intercepts these connection attempts with spoofed responses containing NAV values, thereby securing data while maintaining coverage.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If unauthorized access points are permitted, then wireless connectivity is improved, but network performance deteriorates

Engineering Contradiction:

Improvewireless connectivityVSAvoidnetwork performance

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The authorized access point performs preliminary actions by monitoring for probe requests directed at unauthorized access points and sending spoofed probe responses with high NAV values before the connection process can consume network resources. This prevents bandwidth theft and maintains network performance while preserving wireless connectivity.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11601813B2Preventing wireless connections to an unauthorized access point on a data communication network using NAV values

Publication Date: 2023.03.07 FORTINET INC

AI summary

Broadcasts of a probe request are detected from a wireless station with the MAC address for an unauthorized access point in order to begin association between the wireless station and the unauthorized access point. Responsive to the probe request detection, a spoofed probe response is transmitted including a MAC address of the unauthorized access point to the station to appear as if sent by the unauthorized access point. The probe response includes a NAV element and the MAC address of the unauthorized access point, the NAV element set at a value high enough to prevent the station from transmitting to the unauthorized access point during a period.