• Review of KIISC
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• v.25 no.6
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• pp.5-12
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• 2015

스마트폰 사용이 대중화됨에 따라 스마트폰 사용인구 증가와 함께 우리의 일상생활과 밀접한 관계를 가지며 영향력을 넓혀가고 있는 가운데, 악성앱을 이용해 개인정보 유출, 불법 과금 유발, 스팸 발송 등 스마트폰 사용자에 피해를 입히며 사회적인 문제를 유발하는 보안 위협의 출현 또한 지속적으로 증가하고 있다. 이러한 문제를 해결하기 위해 전 세계 보안업체, 연구소, 학계 등에서는 스마트폰 악성앱을 탐지하고 대응하기 위한 기술을 연구개발하고, 앱 마켓에서는 악성앱을 탐지하기 위한 분석 시스템을 도입하는 등 다양한 활동이 진행되고 있다. 하지만 악성앱 또한 기존의 탐지 및 대응 기술을 우회하는 등 생존율을 높이기 위한 방향으로 점차 지능화 정교화되는 양상을 보이고 있다. 최근 이러한 특징은 앱 마켓 등에서 도입하고 있는 대량의 앱에 대한 자동화된 런타임 분석을 수행하는 동적분석 시스템/서비스를 대상으로 많이 발생되고 있는데, 동적분석의 환경적, 시간적 제약 등을 이용하여 분석기술을 회피하는 기법을 주로 사용하고 있다. 이와 관련하여 본 논문에서는 기존의 동적분석 기술을 우회하는 악성앱 분석회피 행위 유형을 분류하고, 이와 관련된 연구 동향에 대한 정보를 제공하고자 한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.374-376
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• 2022

The Malware App Analysis Tool is a system that analyzes Android-based apps by the AI-based algorithm defined in the tool and detects whether malware code is included. Currently, as the spred of smartphones is activated, crimes using malware apps have increased, and accordingly, security for malware apps is required. Android operating systems used in smartphones have a share of more than 70% and are open-source-based, so not only will there be many vulnerabilities and malware, but also more damage to malware apps, increasing demand for tools to detect and analyze malware apps. However, this paper is proposed because there are many difficulties in designing and developing a malware app analysis tool because the security functional requirements for the malware app analysis tool are not clearly specified. Through the developed protection profile, technology can be improved based on the design and development of malware app analysis tools, safety can be secured by minimizing damage to malware apps, and furthermore, trust in malware app analysis tools can be guaranted through common criteria.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.455-457
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• 2021

App is used on mobile devices such as smartphones and also has malicious code, which can be divided into normal and malicious depending on the presence or absence of hacking codes. Because there are many kind of malware, it is difficult to detect directly, we propose a method to detect malicious app using AI. Most of the existing methods are to detect malicious app by extracting features from malicious app. However, the number of types have increased exponentially, making it impossible to detect malicious code. Therefore, we would like to propose two more methods besides detecting malicious app by extracting features from most existing malicious app. The first method is to learn normal app to extract normal's features, as opposed to the existing method of learning malicious app and find abnormalities (malicious app). The second one is an 'ensemble technique' that combines the existing method with the first proposal. These two methods need to be studied so that they can be used in future mobile environment.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.3
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• pp.159-168
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• 2017

Smartphone malware has increased because Smartphone users has increased and smartphones are widely used in everyday life. Since 2012, Android has been the most mobile operating system. Owing to the open nature of Android, countless malware are in Android markets that seriously threaten Android security. Most of Android malware detection program does not detect malware to which bypass techniques apply and also does not detect unknown malware. In this paper, we propose lightweight method for detection of Android malware using static analysis and deep learning techniques. For experiments we crawl 7,000 apps from the Google Play Store and collect 6,120 malwares. The result show that proposed method can achieve 98.05% detection accuracy. Also, proposed method can detect about unknown malware families with good performance. On smartphones, the method requires 10 seconds for an analysis on average.

• Journal of Software Assessment and Valuation
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• v.15 no.1
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• pp.11-24
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• 2019

Using cross-platform development frameworks, mobile app developers can easily implement mobile apps for multiple platforms in one step. The frameworks also provides adversaries with the ability to write malicious code once, and then run it anywhere for other platforms. In this paper, we analyze the ratio of benign and malicious apps written by cross-platform development frameworks for Android apps collected from AndroZoo's site. The analysis results show that the percentage of benign apps written in the frameworks continues to increase, accounting for 45% of all benign apps in 2018. The percentage of malicious apps written in the frameworks accounted for 25% of all malicious apps in 2015, but that percentage has declined since then. This study provides useful information to make a suitable choice when app developers face several challenges in cross platform app development.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.902-904
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• 2022

스마트폰 사용자 수가 증가함에 따라 스미싱, 몸캠피싱, 메신저 피싱과 같은 정보통신망을 이용한 범죄가 큰 폭으로 증가하고 있다. 이러한 범죄 피해는 다양한 연령층에서 발생하고 있다. 본 논문에서는 국내 모바일 운영체제 점유율이 가장 높은 안드로이드 운영체제를 대상으로 하는 패킹된 악성 앱 언패킹을 수행하고 시그니처 기반 탐지 도구인 Yara 를 통해 악성 앱에 사용된 패커를 식별하는 통합 악성 앱 언패킹 시스템을 제공하여 악성 앱을 이용한 범죄 대응에 도움을 줄 수 있을 것으로 기대된다.

• Journal of the Korea Convergence Society
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• v.8 no.3
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• pp.49-61
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• 2017

Recently, convenience and usability are increasing with the development and deployment of various mobile applications on the Android platform. However, important information stored in the smartphone is leaked to the outside without knowing the user since the malicious mobile application is continuously increasing. A variety of mobile vaccines have been developed for the Android platform to detect malicious apps. Recently discovered server-based polymorphic(SSP) malicious mobile apps include obfuscation techniques. Therefore, it is not easy to detect existing mobile vaccines because some other form of malicious app is newly created by using SSP mechanism. In this paper, we analyze the correlation between the similarity of the method in the DEX file constituting the core malicious code and the permission similarity measure through APK de-compiling process for the SSP malicious app. According to the analysis results of DEX method similarity and permission similarity, we could extract the characteristics of SSP malicious apps and found the difference that can be distinguished from the normal app.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.3
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• pp.357-367
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• 2020

According to Symantec's 2018 internet security threat report, The number of new mobile malware variants increased by 54 percent in 2017, as compared to 2016. And last year, there were an average of 24,000 malicious mobile applications blocked each day. Existing signature-based technologies of malware detection have limitations. So, malware detection technique through machine learning is being researched to detect malware variant. However, even in the case of applying machine learning, if the proper features of the malware are not properly selected, the machine learning cannot be shown correctly. We are focusing on feature selection method to find the features of malware variant in this research.

• Journal of Internet Computing and Services
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• v.14 no.6
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• pp.125-139
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• 2013

Distribution of malicious applications developed by attackers is increasing along with general normal applications due to the openness of the Android-based open market. Mechanism that allows more accurate ways to distinguish normal apps and malicious apps for common mobile devices should be developed in order to reduce the damage caused by the rampant malicious applications. This paper analysed the normal event pattern from the most highly used game apps in the Android open market to analyse the event pattern from normal apps and malicious apps of mobile devices that are based on the Android platform, and analysed the malicious event pattern from the malicious apps and the disguising malicious apps in the form of a game app among 1260 malware samples distributed by Android MalGenome Project. As described, experiment that extracts normal app and malicious app events was performed using Strace, the Linux-based system call extraction tool, targeting normal apps and malicious apps on Android-based mobile devices. Relevance analysis for each event set was performed on collected events that occurred when normal apps and malicious apps were running. This paper successfully extracted event similarity through this process of analyzing the event occurrence characteristics, pattern and distribution on each set of normal apps and malicious apps, and lastly suggested a mechanism that determines whether any given app is malicious.

• Journal of KIISE
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• v.41 no.9
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• pp.707-714
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• 2014

In general, the benign apps transmit privacy information to the external to provide service to users as the malicious app does. In other words, the behavior of benign apps is similar to the one of malicious apps. Thus, the benign app can be easily manipulated for malicious purposes. Therefore, the malicious apps as well as the benign apps should notify the users of the possibility of privacy information leakage before installation to prevent the potential malicious behavior. In this paper, We propose the method to detect leakage of privacy information on the android app by analyzing API inter-dependency and shortest distance. Also, we present LeakDroid which detects leakage of privacy information on Android with the above method. Unlike dynamic approaches, LeakDroid analyzes Android apps on market site. To verify the privacy information leakage detection of LeakDroid, we experimented the well-known 250 malicious apps and the 1700 benign apps collected from Android Third party market. Our evaluation result shows that LeakDroid reached detection rate of 96.4% in the malicious apps and detected 68 true privacy information leakages inside the 1700 benign apps.