• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.1
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• pp.31-40
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• 2024

Recently, static analysis-based signature and pattern detection technologies have limitations due to the advanced IT technologies. Moreover, It is a compatibility problem of multiple architectures and an inherent problem of signature and pattern detection. Malicious codes use obfuscation and packing techniques to hide their identity, and they also avoid existing static analysis-based signature and pattern detection techniques such as code rearrangement, register modification, and branching statement addition. In this paper, We propose an LLVM IR image-based automated static analysis of malicious code technology using machine learning to solve the problems mentioned above. Whether binary is obfuscated or packed, it's decompiled into LLVM IR, which is an intermediate representation dedicated to static analysis and optimization. "Therefore, the LLVM IR code is converted into an image before being fed to the CNN-based transfer learning algorithm ResNet50v2 supported by Keras". As a result, we present a model for image-based detection of malicious code.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.5
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• pp.1313-1322
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• 2016

Recently, many virus and hacking attacks on public organizations and financial institutions by internet are becoming increasingly intelligent and sophisticated. The Advanced Persistent Threat has been considered as an important cyber risk. This attack is basically accomplished by spreading malicious codes through complex networks. To detect and extract PE files in smart manufacturing industry networks, an efficient processing method which is performed before analysis procedure on malicious codes is proposed. We implement a preprocessor of open intrusion detection system Snort for fast extraction of PE files and install on a hardware sensor equipment. As a result of practical experiment, we verify that the network sensor can extract the PE files which are often suspected as a malware.

• International journal of advanced smart convergence
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• v.8 no.4
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• pp.47-57
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• 2019

We examine the weaknesses of the existing OOXML-based MS-Word file structure, and analyze how data concealment and forgery are performed in MS-Word digital documents. In case of forgery by including hidden information in MS-Word digital document, there is no difference in opening the file with the MS-Word Processor. However, the computer system may be malfunctioned by malware or shell code hidden in the digital document. If a malicious image file or ZIP file is hidden in the document by using the structural vulnerability of the MS-Word document, it may be infected by ransomware that encrypts the entire file on the disk even if the MS-Word file is normally executed. Therefore, it is necessary to analyze forgery and alteration of digital document through internal structure analysis of MS-Word file. In this paper, we designed and implemented a mechanism to detect this efficiently and automatic detection software, and presented a method to proactively respond to attacks such as ransomware exploiting MS-Word security vulnerabilities.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.01a
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• pp.267-269
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• 2015

본 논문에서는 고성능 컴퓨팅 시스템의 성능 향상을 위한 효율적인 동적 작업부하 균등화 정책을 제안한다. 이 정책은 시스템 자원인 CPU와 메모리를 효율적으로 사용하여 고성능 컴퓨팅 시스템의 처리량을 최대화하고, 각 작업의 수행시간을 최소화한다. 또한 이 정책은 수행중인 작업의 메모리 요구량과 각 노드의 부하 상태를 파악하여 작업을 동적으로 할당한다. 이때 작업을 할당 받은 노드가 과부하 상태가 되면 다른 노드로 작업을 이주시켜 각 노드의 작업부하를 균등하게 유지함으로써 작업의 대기시간을 줄이고, 각 작업의 수행시간을 단축한다. 본 논문에서는 시뮬레이션을 통하여 제안하는 동적 작업부하 균등화 정책이 기존의 메모리 기반의 작업부하 균등화 정책에 비해 고성능 컴퓨팅 시스템의 성능 향상 면에서 우수함을 보인다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.770-773
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• 2012

특정 기업 및 국가를 대상으로 하는 APT(Advanced Persistent Threat)공격의 경우 특정 시스템을 겨냥하여 제작되기 때문에 기존의 시그니처 기반의 악성코드 탐지 방식으로는 해당 악성코드를 탐지할 수 없다. 따라서 알려지지 않은 악성코드를 탐지할 수 있는 행위 기반의 악성코드 탐지 방식이 최근 이슈화되었다. 본 논문에서는 연구되고 있는 행위 분석 기반의 악성코드 탐지 방식들을 분석함으로써 향후 행위 기반 악성코드 탐지 기술 개발 및 연구에 기여하고자 한다.

• International journal of advanced smart convergence
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• v.12 no.1
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• pp.149-156
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• 2023

OOXML-based MS-Office digital files are extensively utilized by businesses and organizations worldwide. However, OOXML-based MS-Office digital files are vulnerable to forgery and corruption attack by including hidden suspicious information, which can lead to activating malware or shell code being hidden in the file. Such malicious code can cause a computer system to malfunction or become infected with ransomware. To prevent such attacks, it is necessary to analyze and detect the corruption of OOXML-based MS-Office files. In this paper, we examine the weaknesses of the existing OOXML-based MS-Office file structure and analyzes how concealment and forgery are performed on MS-Office digital files. As a result, we propose a system to detect hidden data effectively and proactively respond to ransomware attacks exploiting MS-Office security vulnerabilities. Proposed system is designed to provide reliable and efficient detection of hidden data in OOXML-based MS-Office files, which can help organizations protect against potential security threats.

• Journal of Platform Technology
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• v.9 no.3
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• pp.3-17
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• 2021

Advanced persistent threat (APT) attacks are attacks aimed at a particular entity as a set of latent and persistent computer hacking processes. These APT attacks are usually carried out through various methods, including spam mail and disguised banner advertising. The same name is also used for files, since most of them are distributed via spam mail disguised as invoices, shipment documents, and purchase orders. In addition, such Infostealer attacks were the most frequently discovered malicious code in the first week of February 2021. CDR is a 'Content Disarm & Reconstruction' technology that can prevent the risk of malware infection by removing potential security threats from files and recombining them into safe files. Gartner, a global IT advisory organization, recommends CDR as a solution to attacks in the form of attachments. There is a program using CDR techniques released as open source is called 'Dangerzone'. The program supports the extension of most document files, but does not support the extension of HWP files that are widely used in Korea. In addition, Gmail blocks malicious URLs first, but it does not block malicious URLs in mail systems such as Naver and Daum, so malicious URLs can be easily distributed. Based on this problem, we developed a 'Dangerzone' program that supports the HWP extension to prevent APT attacks, and a Chrome extension that performs URL checking in Naver and Daum mail and blocking banner ads.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.287-294
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• 2016

APT attack aimed at the interruption of information and communication facilities and important information leakage of companies. it performs an attack using zero-day vulnerabilities, social engineering base on collected information, such as IT infra, business environment, information of employee, for a long period of time. Fragmentary response to cyber threats such as malware signature detection methods can not respond to sophisticated cyber-attacks, such as APT attacks. In this paper, we propose a cyber intrusion detection model for countermeasure of APT attack by utilizing heterogeneous system log into big-data. And it also utilizes that merging pattern-based detection methods and abnormality detection method.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.369-370
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• 2014

본 논문에서는 안드로이드 환경에서 클래스 반사(Reflection)과 예외처리를 이용하여 안드로이드 보호 시스템을 우회하여 임의의 코드를 수행할 수 있는 방법을 제시한다. 일반적인 자바 환경과는 달리 안드로이드 환경에서는 보안 강화를 위해 APK 파일 내 루트 디렉토리의 클래스 파일만을 반사를 통해 동적 로딩이 가능하다. 하지만, 본 논문에서는 클래스 반사와 예외 처리를 이용하여 임의의 디렉토리 내 파일을 로딩 및 동적 실행할 수 있는 방법을 보이며 이 방법은 저자가 알기로는 기존에 알려지지 않은 방법이다. 이를 기반으로, 본 논문에서는 AES 암호와 동적 로딩을 이용하여, 모바일 어플리케이션의 내부 코드를 은폐하는 기법을 제안한다. 제안기법을 활용 시, 첫째 공격자의 입장에서는 내부 코드를 은폐하여 백신을 우회하는 악성코드 제작이 가능하고, 둘째, 프로그램 제작자의 입장에서는 핵심 알고리즘을 은폐하여 저작권을 보호하는 코드 제작이 가능하다. 안드로이드 버전 4.4.2(Kitkat)에서 프로토타입을 구현하여 제안 기법의 실효성을 보였다.

• Journal of Advanced Navigation Technology
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• v.17 no.3
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• pp.314-325
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• 2013

Smartwork is future-oriented work-environment to bring swift business transaction and convenient for users. In domestic and foreign various countries, It's already prompting introduction of smartwork. Users process work to access frequently from the outside in smartwork that's a similar client/server environment to existing Cloud Computing environment. Necessary of user authentication is increasing to be solvable to security vulnerability because there is possibility that malware flows in and leaks company's confidential information by unauthorized users especially in smartwork environment. Therefore we propose User Authentication scheme based face recognition is applicable to smartwork environment to analyze established User Authentication scheme. environment.