NAT Device Detection via Traffic Log Classification

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Solution Overview

Problem

Unauthorized Network Address Translation (NAT) devices pose a significant security threat as they can provide unrestricted access to network-connected devices and data, and existing technologies struggle to effectively detect and distinguish between authorized and unauthorized NAT devices, especially wireless NATs which can allow unauthorized access from considerable distances.

Innovation Solution

A classifier device is trained using labeled network traffic features extracted from actual and artificial traffic logs to differentiate between NAT devices and end host devices by analyzing features such as unique contacted IP addresses, User-Agent strings, and network transaction patterns, allowing for accurate classification and detection of NAT devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional detection methods are used to identify NAT devices, then the detection process is simple, but the accuracy of distinguishing between authorized and unauthorized NAT devices is low

Engineering Contradiction:
Improvedetection accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by collecting and storing network traffic logs before detection is needed. These logs contain behavioral patterns that are extracted and stored in advance, allowing the classifier to make accurate predictions without performing complex real-time analysis during actual detection operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates copies of network traffic data in the form of structured logs and extracted features. By copying and storing behavioral patterns from multiple time windows, the system builds a training dataset that replicates real network conditions, enabling accurate classification without requiring the original complex traffic data during detection.

Inventive Principle:
Principle #26Copying

2Measurement precision

If network traffic analysis is performed in real-time to detect NAT devices, then detection accuracy improves, but the processing time and computational resources increase

Engineering Contradiction:
ImproveNAT device detection accuracyVSAvoiddetection processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system extracts network traffic features and creates structured logs in advance, before detection is required. By pre-processing the traffic data and storing extracted features such as packet counts, flow characteristics, and behavioral patterns, the system eliminates the need for time-consuming real-time feature extraction during actual NAT device detection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The detection process is segmented into distinct phases: traffic log collection, feature extraction, classifier training, and detection execution. By dividing the complex real-time analysis into separate preprocessing and detection stages, the system can perform computationally intensive operations in advance and execute rapid classification when needed.

Inventive Principle:
Principle #1Segmentation

3Reliability

If comprehensive network traffic features are collected to improve classification accuracy, then the detection reliability increases, but the data processing complexity and storage requirements increase

Engineering Contradiction:
Improveclassification reliabilityVSAvoiddata processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system extracts specific relevant features from comprehensive network traffic data, such as packet counts, flow characteristics, and behavioral patterns. By taking out only the essential features needed for NAT device classification rather than processing all raw traffic data, the system maintains high classification reliability while reducing processing and storage complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If multiple time windows are used to collect traffic logs for training the classifier, then the classifier accuracy improves, but the training time and computational resources increase

Engineering Contradiction:
Improveclassifier accuracyVSAvoidclassifier training time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system collects network traffic logs across multiple time windows in advance and performs feature extraction before classifier training is needed. By preparing the training dataset with features from multiple temporal contexts beforehand, the system can train the classifier efficiently using pre-processed data rather than performing repeated analysis during the training process.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS9942256B2Detecting network address translation devices in a network based on network traffic logs
Publication Date: 2018.04.10 CISCO TECHNOLOGY INC
  • US9942256B2 patent drawing
  • US9942256B2 patent drawing
  • US9942256B2 patent drawing

AI summary

Actual traffic logs of network traffic to and from host devices in a network are collected over time. Artificial traffic logs for each of multiple artificial network address translation (NAT) devices are generated from the actual traffic logs. The actual traffic logs and the artificial traffic logs are labeled as being indicative of non-NAT devices and NAT devices, respectively, to produce labeled traffic logs. From the labeled traffic logs for each artificial NAT device and each non-NAT device, respective, correspondingly labeled, network traffic features indicative of whether the device behaves like a NAT device or a non-NAT device are extracted. A classifier device is trained using the network traffic features extracted for each artificial NAT device and each non-NAT device to classify between an actual NAT device and an actual non-NAT device based on further actual traffic logs.