Browser Log Matching for Analysis Avoidance Code Detection

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Solution Overview

Problem

Existing methods struggle to identify and analyze 'analysis avoidance code' that exploits browser-specific functions or implementation differences between real browsers and pseudo-browsers, making it difficult to detect malicious websites using Drive-by Download attacks.

Innovation Solution

An analysis apparatus and method that utilize the differences between real browser and pseudo-browser environments to identify 'analysis avoidance code' by creating transfer graphs from access logs and matching them to detect malicious URLs, allowing for the identification of JavaScript codes that avoid analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pseudo-browser is used to simulate a real browser environment for analyzing malicious websites, then the ability to execute and analyze JavaScript codes is improved, but the ability to detect analysis avoidance codes that exploit browser-specific functions deteriorates

Engineering Contradiction:
ImproveJavaScript execution capabilityVSAvoidanalysis avoidance code detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

Instead of trying to make the pseudo-browser perfectly replicate the real browser, the invention inverts the approach by using the real browser to analyze the malicious website and comparing its behavior with the pseudo-browser. The analysis avoidance code is detected by identifying discrepancies in execution results between the two browsers, turning the limitation of the pseudo-browser into a detectable signal.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention introduces an intermediary analysis mechanism that captures and compares the execution traces of both the real browser and pseudo-browser. This intermediary layer monitors the control flow graphs and execution paths, identifying when the analysis avoidance code causes divergent behavior between the two browser environments.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If browser-specific functions are used for browser fingerprinting to improve attack precision, then the success rate of Drive-by Download attacks is improved, but the detectability of the attack code deteriorates

Engineering Contradiction:
Improvebrowser identification accuracyVSAvoidattack code detection
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The invention detects browser-specific function usage by inverting the detection approach: instead of trying to identify the browser type directly, it executes the malicious code in a controlled environment and observes whether browser-specific behaviors are triggered. The analysis avoidance code is identified by the异常 patterns it creates when exploiting these browser-specific functions.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention changes the parameter of browser environment from a static simulation (pseudo-browser) to a dynamic comparison between real and simulated environments. By varying the browser configuration parameters and observing execution differences, the system can detect when analysis avoidance codes are exploiting specific browser implementations.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If existing analysis methods are used to detect malicious websites, then the detection process is simplified, but the ability to identify analysis avoidance codes deteriorates

Engineering Contradiction:
Improveanalysis process simplicityVSAvoidanalysis avoidance code identification
Core Design Contradiction:
Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The invention segments the analysis process into distinct phases: (1) executing the malicious code in both real and pseudo-browsers, (2) capturing execution traces separately, (3) comparing the traces to identify discrepancies, and (4) flagging potential analysis avoidance codes. This segmentation maintains operational simplicity while enabling sophisticated detection through systematic comparison.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3547193B1Analysis apparatus, analysis method and analysis program
Publication Date: 2021.11.24 NIPPON TELEGRAPH & TELEPHONE CORP
  • EP3547193B1 patent drawingFigure 1
  • EP3547193B1 patent drawingFigure 2(a)~2(b)
  • EP3547193B1 patent drawingFigure 3

AI summary

An analysis apparatus (10) has a transfer path matching unit (151) that is provided with a real browser log La and a browser emulator log Lb as input and identifies, as a specific transfer path, a transfer path that is not transferred to a malicious URL on a pseudo-browser where the transfer path is transferred to the malicious URL on a real browser, based on the malicious URL information in a malicious URL database (14), and an analysis avoidance code identification unit (152) that identifies an analysis avoidance code that avoids analysis by utilizing a browser-specific function or an implementation difference between the real-browser and the pseudo-browser, among script codes that are executed on a website, based on the specific transfer path.