RNN Autoencoder DNS Traffic Analysis for Tunneling Detection

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Solution Overview

Problem

DNS tunneling attacks exploit the clear-text nature of the DNS protocol to evade network defenses and exfiltrate sensitive data, posing a significant threat to connected devices, as existing security solutions are ineffective against unsophisticated attackers.

Innovation Solution

Employing an autoencoder trained with a modified loss function to differentiate between benign and malicious DNS data by successfully encoding benign data and failing to encode malicious data, using a recurrent neural network (RNN) architecture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If DNS protocol is used for device connectivity, then device connectivity is enabled, but the protocol works in clear text allowing DNS tunneling attacks to evade network defenses

Engineering Contradiction:
Improvedevice connectivityVSAvoidDNS tunneling attacks
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

An autoencoder neural network is introduced as an intermediary component between the DNS protocol and network defenses. The autoencoder learns the normal encoding patterns of legitimate DNS traffic and identifies anomalies that indicate tunneling attacks, thereby enabling connectivity while blocking malicious traffic.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the parameter being monitored from simple DNS protocol presence to the encoding characteristics of DNS data. By analyzing how DNS data is encoded rather than just whether DNS traffic exists, the system can distinguish between legitimate and malicious traffic while maintaining protocol functionality.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If existing security solutions are used, then basic protection is provided, but they are ineffective against unsophisticated attackers using DNS tunneling toolkits

Engineering Contradiction:
Improvebasic protectionVSAvoiddetection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

Traditional mechanical security solutions (rule-based filters, signature matching) are replaced with a neural network-based autoencoder. This substitution enables the system to learn complex patterns in DNS traffic encoding, achieving higher detection precision against varied tunneling techniques without requiring manual rule updates.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The autoencoder trains itself on DNS traffic data to learn normal encoding patterns without requiring manual configuration or rule updates. This self-service capability allows the system to adapt to new tunneling techniques automatically, maintaining high detection accuracy against unsophisticated attackers using various toolkits.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If autoencoder with modified loss function is employed, then malicious DNS traffic is accurately identified, but system complexity increases

Engineering Contradiction:
Improvemalicious traffic identificationVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The loss function parameter is modified to penalize false negatives (missing malicious traffic) more heavily than false positives. This parameter change in the training objective enables the autoencoder to achieve high precision in identifying malicious traffic while the model architecture remains relatively simple, balancing detection accuracy with system complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12411947B2DNS tunneling detection and prevention
Publication Date: 2025.09.09 CHECK POINT SOFTWARE TECH LTD
  • US12411947B2 patent drawing
  • US12411947B2 patent drawing
  • US12411947B2 patent drawing

AI summary

Methods and devices are provided for differentiating between benign DNS data and malicious DNS data included in DNS traffic using an autoencoder. The autoencoder receives input DNS data and is trained to successfully encode the input DNS data when the input DNS data is benign DNS data and to fail to encode the input DNS data when the input DNS data is malicious DNS data. The autoencoder is trained using a modified loss function having a large weight when successfully encoding malicious DNS data.