• Journal of Internet Computing and Services
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• v.13 no.2
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• pp.51-57
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• 2012

The warming up of the recent competition in the smart phone industry followed by rapid increase of open platforms and app stores have led the mobile terminals to adopt the general purpose operating system. The mobile device utilizing this OS is vulnerable to mobile malignant code which is highly transferable. As a result, the scale of mobile attack and harm increase. However, compared to the malicious code and virus which keep increasing, the elements for security to prevent are insufficient. Therefore, this paper describe about the Context Aware Service that eliminates the potentially risky elements on the smart phone service, which could threaten the usability of the service including invasion of personal information. The proposed system prevents from disclosure of personal information by giving the procedure of information, and realizes the service that is able to change the sequence of identifying the users' information to prepare for emergency.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06b
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• pp.52-54
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• 2011

급속하게 성장하고 있는 스마트폰 시장에서 사용자의 수가 늘어감에 따라 다양한 이슈들이 대두되고 있다. 특히 스마트폰에는 많은 개인정보들이 저장되어 있어, 분실 또는 악성 코드로 인한 정보 유출로 막대한 금전적 피해를 야기할 수 있기 때문에 보안 기법에 대한 연구 필요성이 강조되고 있다. 개방형플랫폼을 지향하고 있는 모바일 운영체제 안드로이드는 다른 폐쇄형 플랫폼보다 보안 취약점이 노출 될 가능성이 높고 실제로 이로 인한 피해 사례들이 보고되고 있다. 본 논문에서는 안드로이드를 플랫폼에서 보안을 강화하기 위해 연구된 여러 보안 기법들을 살펴보고 특징에 따라 분류해본다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.3
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• pp.643-653
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• 2018

Xamarin is a representative cross-platform development framework that allows developers to write mobile apps in C# for multiple mobile platforms, such as Android, iOS, or Windows Phone. Using Xamarin, mobile app developers can reuse existing C# code and share significant code across multiple platforms, reducing development time and maintenance costs. Meanwhile, malware authors can also use Xamarin to spread malicious apps on more platforms, minimizing the time and cost of malicious app creation. In order to cope with this problem, it is necessary to analyze and detect malware written with Xamarin. However, little studies have been conducted on static analysis methods of the apps written in Xamarin. In this paper, we examine the structure of Android apps written with Xamarin and propose a static analysis technique for the apps. We also demonstrate how to statically reverse-engineer apps that have been transformed using code obfuscation. Because the Android apps written with Xamarin consists of Java bytecode, C# based DLL libraries, and C/C++ based native libraries, we have studied static reverse engineering techniques for these different types of code.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.321-322
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• 2022

스마트폰 사용자가 늘어남에 따라 갖춰줘야 할 보안성이 취약하여, 다양한 바이러스 및 악성코드 위험에 노출되어 있다. 안드로이드는 운영체제 중 가장 많이 사용되는 운영체제로, 개방성이 높으며 수많은 악성 앱 및 바이러스가 마켓에 존재하여 위험에 쉽게 노출된다. 2년 넘게 이어진 코로나 바이러스(Covid-19)으로 인해 꾸준히 위험도가 높아진 피싱공격(Phshing attack)은 현재 최고의 스마트폰 보안 위협 Top10에 위치한다. 본 논문에서는 딥러닝 기반 자연어처리 기술을 통해 피싱 공격 대응 방법 제안 및 실험 결과를 도출하고, 또한 향후 제안 방법을 보완하여 피싱 공격 및 다양한 모바일 보안 위협에 대응할 수 있는 앱을 설계할 것이다.

• 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.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.267-272
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• 2014

Customers who register at mobile banking service through startphone has 40Mil in first quarter of 2014, which was increased 8.5%(3.6Mil) compare to figure from end of year 2013. Average 1 trillion 627.6billion won is dealing through smartphone banking in daily and three for increased psychological bullying caused by malignant code which change normality to malignant. The results of the analysis current state of affairs of personal information collection management authority required in finance smartphone app service and also recommend solution for protecting finance consumers plans to minimized collecting personal information in smartphone finance app service.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.5
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• pp.309-316
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• 2014

It is easy to reverse engineer an Android app package file(APK) and get its decompiled source code. Therefore, attackers obtains economic benefits by illegally using the decompiled source code, or modifies an app by inserting malware. To address these problems in Android, we propose an APK overwrite scheme that protects apps against illegal modification of themselves by using a new anti-reverse engineering technique. In this paper, the targets are the apps which have been written by any programmer. For a target app (original app), server system (1) makes a copy of a target app, (2) encrypts the target app, (3) creates a stub app by replacing the DEX (Dalvik Executable) of the copied version with our stub DEX, and then (4) distributes the stub app as well as the encrypted target app to users of smartphones. The users downloads both the encrypted target app and the corresponding stub app. Whenever the stub app is executed on smartphones, the stub app and our launcher app decrypt the encrypted target app, overwrite the stub app with the decrypted target one, and executes the decrypted one. Every time the target app ends its execution, the decrypted app is deleted. To verify the feasibility of the proposed scheme, experimentation with several popular apps are carried out. The results of the experiment demonstrate that our scheme is effective for preventing reverse engineering and tampering of Android apps.

• Information and Communications Magazine
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• v.29 no.8
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• pp.65-71
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• 2012

스마트폰을 비롯한 다양한 모바일 기기 보급이 급속도로 증가하고 있고, 이들 기기에 저장된 각종 개인정보에 대한 불법적 접근을 노라는 악성 앱들로 인한 피해가 발생하고 있다. 이들 위변조 앱 출현의 원인 중의 하나는 앱 실행화일의 역컴파일이 쉽기 때문이다. 앱 역컴파일이 쉽게 이루어지지 않도록 하기 위한 기술 중의 하나가 코드 난독화 기술이다. 따라서, 본 고에서는 일반적인 난독화 기술들을 분류하고, 현존하는 안드로이드, 아이폰, 윈도폰에 적용가능한 난독화 도구들의 기능에 대하여 조사 분석한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.857-860
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• 2013

스마트폰의 다양하고 편리한 기능은 휴대전화기 시장의 급속한 성장을 이루어 최근에는 3000만 사용자 수를 넘어서고 있지만, 악성코드와 같은 공격으로 인한 보안 사고 또한 증가하고 있다. 개방성을 지향하는 안드로이드 플랫폼에서는 스미싱과 같은 신종 공격으로 인해 보안 사고가 최근 크게 이슈가 되고 있는 상황이다. 이러한 취약성을 보완하기 위해 기존 스마트폰 운영체제와 별도의 도메인을 분리하여 금융거래나 사용자의 중요 정보는 별도의 보안 운영체제에서 처리하는 모바일 가상화 기술이 대두되고 있다. 향후 이러한 모바일 가상화 기술이 대중화될 경우, 일반적인 포렌식 조사 절차로는 현장에서 확보한 스마트폰의 보안 영역에서는 사건 조사에 필요한 증거 수집이 불가능할 수 있다. 따라서 본 논문에서는 최근의 모바일 가상화 기술을 살펴보고, 이를 바탕으로 가상화 플랫폼 기반 모바일 장비의 포렌식 조사 방안에 대해 살펴보고자 한다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.4
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• pp.829-838
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• 2015

As the number of smartphone users have increased, many kinds of malwares have emerged. Unlike existing malwares, spyware can be installed normally after user authentication and agreement according to security policy. For this reason, it is not easy to catch spywares involving harmful functionalities to users by using existing malware detection system. Therefore, our paper focuses on study about detecting mainly wiretapping spywares among them by developing a new wiretapping detection model and application. Specifically, this study conducts to find out power consumption on each application and modular and network consumption to detect voice wiretapping so Open Source Project Power Tutor is used to do this. The risk assessment of wiretapping is measured by gathered all power consumption data from Open Source Project Power Tutor. In addition, developed application in our study can detect at-risk wiretapping spyware through collecting and analyzing data. After we install the application to the smartphone, we collect needed data and measure it.