• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.7
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• pp.1290-1295
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• 2016

Recently, as mobile internet usage has been increasing rapidly, malware attacks through user's web browsers has been spreading in a way of social engineering or drive-by downloading. Existing defense mechanism against drive-by download attack mainly focused on final download sites and distribution paths. However, detection and prevention of injection sites to inject malicious code into the comprised websites have not been fully investigated. In this paper, for the purpose of improving defense mechanisms against these malware downloads attacks, we focus on detecting the injection site which is the key source of malware downloads spreading. As a result, in addition to the current URL blacklist techniques, we proposed the enhanced method which adds features of detecting the injection site to prevent the malware spreading. We empirically show that the proposed method can effectively minimize malware infections by blocking the source of the infection spreading, compared to other approaches of the URL blacklisting that directly uses the drive-by browser exploits.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.1993-1998
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• 2008

Web robot engine for searching web sever vulnerability and malicious code is proposed in this paper. The main web robot function is based on searching technology which is derived from analyses of private information threat. We implemented the detecting method for phishing, pharming and malicious code on homepage under vulnerable surroundings. We proposed a novel approachm which is independent of any specific phishing implementation. Our idea is to examine the anomalies in web pages.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.213-216
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• 2021

기술이 발전함에 따라 악성코드 또한 함께 발전하여 보안 위협이 증가되고 있다. 특히 PowerShell 과 같은 스크립트 언어를 사용하여 포렌식이 어려운 Fileless 악성코드가 지속적으로 증가하고 있다. 이에 본 논문에서 PowerShell 데이터셋을 활용하여 기존 패턴은 탐지할 수 없는 한계점을 가진 시그니처 또는 휴리스틱 기반 탐지 기법을 보완하여 기존의 악성코드들을 학습 및 새로운 악성코드를 추측하는 것이 가능한 심층 학습 기술, Graph Convolutional Networks 과 자카드 유사도를 활용하여 기존의 방식에 비해 더 효율적으로 탐지를 이루어 내는지를 판단해보려한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.933-943
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• 2022

As the Internet develops and the utilization rate of computers increases, the threats posed by malware keep increasing. This leads to the demand for a system to automatically analyzes a large amount of malware. In this paper, an automatic malware analysis technique using a deep learning algorithm is introduced. Our proposed method uses CNN (Convolutional Neural Network) to analyze the malicious features represented as images. To reflect semantic information of malware for detection, our method uses the opcode frequency data of binary for image generation, rather than using bytes of binary. As a result of the experiments using the datasets consisting of 20,000 samples, it was found that the proposed method can detect malicious codes with 91% accuracy.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.1
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• pp.105-115
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• 2019

Recently, intelligent Android malicious codes have become difficult to detect malicious behavior by static analysis alone. Malicious code with SO file, dynamic loading, and string obfuscation are difficult to extract information about original code even with various tools for static analysis. There are many dynamic analysis methods to solve this problem, but dynamic analysis requires rooting or emulator environment. However, in the case of dynamic analysis, malicious code performs the rooting and the emulator detection to bypass the analysis environment. To solve this problem, this paper investigates a variety of root detection schemes and builds an environment for bypassing the rooting detection in real devices. In addition, SDK code hooking module for Android malicious code analysis is designed using Xposed, and intent tracking for code flow, dynamic loading file information, and various API information extraction are implemented. This work will contribute to the analysis of obfuscated information and behavior of Android Malware.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.613-621
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• 2019

Recently, with the development of the Internet of Things (IoT) and cloud computing technologies, security threats have increased as malicious codes infect IoT devices, and new malware spreads ransomware to cloud servers. In this study, we propose a threat-detection technique that checks obfuscated script patterns to compensate for the shortcomings of conventional signature-based and behavior-based detection methods. Proposed is a malicious code-detection technique that is based on malicious script-pattern analysis that can detect zero-day attacks while maintaining the existing detection rate by registering and checking derived distribution patterns after analyzing the types of malicious scripts distributed through websites. To verify the performance of the proposed technique, a prototype system was developed to collect a total of 390 malicious websites and experiment with 10 major malicious script-distribution patterns derived from analysis. The technique showed an average detection rate of about 86% of all items, while maintaining the existing detection speed based on the detection rule and also detecting zero-day attacks.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.428-430
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• 2012

악성코드의 위협이 점차 증가하고 있다. 악성코드를 보다 잘 탐지하기 위해 의미 구조를 기반으로 탐지하는 안티바이러스 프로그램이 필요하게 되었다. 의미구조를 기반으로 악성코드를 검출하기 위해서는 프로그램의 어떤 행동이 나쁜 행동인지를 구체적으로 서술하는 것이 필요하다. 이 논문에서는 악성코드의 행동을 형식적으로 나타내는 기술 언어를 만들고 그것이 얼마나 표현가능한지를 악성코드의 행동을 직접 표현해 봄으로써 구체적으로 설명한다. 이 기술 언어를 사용하여 특정 프로그램과 기술 언어를 입력으로 받아 악성코드인지 여부를 알아내는 정적 분석기를 만들 수 있을 것이다. 여기서 제시하는 행동 기술 언어는 프로그램의 행동을 구체적으로 고차원으로 표현할 수 있고, 악성코드의 대표적인 행동들을 충분히 담을 수 있을 만큼 강력하다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.432-435
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• 2022

최근 IT 산업의 지속적인 발전으로 사용자들을 위협하는 악성코드, 피싱, 랜섬웨어와 같은 사이버 공격 또한 계속해서 발전하고 더 지능화되고 있으며 변종 악성코드도 기하급수적으로 늘어나고 있다. 지금까지의 시그니처 패턴 기반의 탐지법으로는 이러한 방대한 양의 알려지지 않은 악성코드를 탐지할 수 없다. 따라서 CNN(Convolutional Neural Network)을 활용하여 악성코드를 탐지하는 기법들이 제안되고 있다. 이에 본 논문에서는 CNN 모델 중 낮은 인식 오류율을 지닌 모델을 선정하여 정확도(Accuracy)와 F1-score 평가 지표를 통해 비교하고자 한다. 두 가지의 악성코드 이미지화 방법을 사용하였으며, 2015 년 이후 ILSVRC 에서 우승을 차지한 모델들과, 추가로 2019 년에 발표된 EfficientNet 을 사용하여 악성코드 이미지를 분류하였다. 그 결과 2 바이트를 한 쌍의 좌표로 변환하여 생성한 256 * 256 크기의 악성코드 이미지를 ResNet-152 모델을 이용해 분류하는 것이 우수한 성능을 보임을 실험적으로 확인하였다.

• The KIPS Transactions:PartC
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• v.13C no.1 s.104
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• pp.45-54
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• 2006

Nowadays, a lot of techniques have been applied for the detection of malicious behavior. However, the current techniques taken into practice are facing with the challenge of much variations of the original malicious behavior, and it is impossible to respond the new forms of behavior appropriately and timely. There are also some limitations can not be solved, such as the error affirmation (positive false) and mistaken obliquity (negative false). With the questions above, we suggest a new method here to improve the current situation. To detect the malicious code, we put forward dealing with the basic source code units through the conceptual graph. Basically, we use conceptual graph to define malicious behavior, and then we are able to compare the similarity relations of the malicious behavior by testing the formalized values which generated by the predefined graphs in the code. In this paper, we show how to make a conceptual graph and propose an efficient method for similarity measure to discern the malicious behavior. As a result of our experiment, we can get more efficient detection rate.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.56-60
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• 2010

악성코드의 기능들이 날로 정교해 지면서 악성 행위를 숨기거나 악성코드 분석이 어렵도록 만들기 위한 기법들이 적용되는 것을 쉽게 볼 수 있다. 이 중 악성코드 분석을 어렵게 만드는 대표적인 방식이 Packing이다. 그러므로 악성코드의 분석을 위해 Packing된 악성코드가 어떤 Packer로 Packing되어 있는 지 확인할 필요가 있다. 그러나 현재 사용하는 대부분의 시그니처 기반 탐지 방식은 오탐율 및 미탐율이 높다. 본 논문에서는 Packer 탐지를 위한 새로운 시그니처 생성 방식을 제안하고 성능을 검증한다.