False Alarm Detection for Malware Scanning via Partial File Hash Matching

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Solution Overview

Problem

Automated malware detection systems face challenges in distinguishing between genuine malware and false alarms, particularly with partial files that can lead to customer frustration and increased technical support requirements, as conventional methods like full file whitelisting and code signing signature checks are ineffective.

Innovation Solution

Implementing a mechanism to detect and suppress false alarms by identifying partial files, temporarily blocking their execution, searching for the original complete file, and comparing hashes to confirm if the partial file is a false alarm, thereby reducing manual intervention and enhancing the reliability of malware detection services.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If automated malware scanning is performed on all files, then detection speed and productivity are improved, but false alarm rate increases due to partial files

Engineering Contradiction:
Improvedetection speedVSAvoidfalse alarm rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary actions by checking file completion status (via extension, download state, or hash verification) before initiating malware scanning. This prevents partial files from being scanned, thereby maintaining high detection speed while eliminating false alarms caused by incomplete files.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If manual review is performed on detected malware, then accuracy of malware identification is improved, but processing time and operational complexity increase

Engineering Contradiction:
Improvemalware identification accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary filtering by identifying and excluding partial files before malware detection. This automated pre-screening achieves high accuracy in distinguishing genuine malware from partial files without requiring manual review, thereby maintaining precision while minimizing time loss.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If comprehensive file scanning is performed, then malware detection capability is improved, but system resource consumption and complexity increase

Engineering Contradiction:
Improvemalware detection capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system extracts and handles partial files separately from the main malware scanning process. By identifying partial files through specific criteria (extensions, download status, hash mismatches) and excluding them beforehand, the system maintains comprehensive malware detection capability while simplifying the overall system architecture and reducing resource consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS11436326B2False alarm detection for malware scanning
Publication Date: 2022.09.06 WITHSECURE CORP (A K A WITHSECURE OYJ)
  • US11436326B2 patent drawing
  • US11436326B2 patent drawing

AI summary

A method of scanning files for malware on a computer system. The method comprises detecting a file to be scanned for malware in the computer system, determining the file being a partial file that comprises only a part of the file content, searching for an original clean file associated with the partial file, wherein the original clean file is a full copy of the partial file, based on finding a candidate original clean file associated with the partial file, calculating a partial hash of the same length as the partial file for the candidate original clean file, and based on determining that partial hashes of the candidate original clean file and the partial file match, signalling a false alarm.