• Journal of KIISE:Computing Practices and Letters
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• v.14 no.8
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• pp.808-812
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• 2008

In recent years, the software vulnerability becomes an important problem to the safety in operating system kernel. Many organizations endeavor to publish patches soon after discovery of vulnerability. In spite of the effort, end-system administrators hesitate to apply the patches to their system. The reasons of hesitation are the reboot disruption and the distrust of patches. To solve this problem we propose a dynamic update system for non-updatable kernel, named DUNK. The DUNK provides: 1) a dynamic update mechanism at function-level granularity to overcome the reboot disruption and 2) a safety verification mechanism to overcome the distrust problem, named MAFIA. In this paper, we describe the design of DUNK and detailed algorithm of MAFIA.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.8
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• pp.1989-2009
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• 2013

How to discover router vulnerabilities effectively and automatically is a critical problem to ensure network and information security. Previous research on router security is mostly about the technology of exploiting known flaws of routers. Fuzzing is a famous automated vulnerability finding technology; however, traditional Fuzzing tools are designed for testing network applications or other software. These tools are not or partly not suitable for testing routers. This paper designs a framework of discovering router protocol vulnerabilities, and proposes a mathematical model Two-stage Fuzzing Test Cases Generator(TFTCG) that improves previous methods to generate test cases. We have developed a tool called RPFuzzer based on TFTCG. RPFuzzer monitors routers by sending normal packets, keeping watch on CPU utilization and checking system logs, which can detect DoS, router reboot and so on. RPFuzzer' debugger based on modified Dynamips, which can record register values when an exception occurs. Finally, we experiment on the SNMP protocol, find 8 vulnerabilities, of which there are five unreleased vulnerabilities. The experiment has proved the effectiveness of RPFuzzer.

• Journal of Information Processing Systems
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• v.17 no.4
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• pp.834-850
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• 2021

IT security companies have been releasing file system filter driver security solutions based on the whitelist, which are being used by several enterprises in the relevant industries. However, in February 2019, a whitelist vulnerability was discovered in Microsoft Edge browser, which allows malicious code to be executed unknown to users. If a hacker had inserted a program that executed malicious code into the whitelist, it would have resulted in considerable damage. File system filter driver security solutions based on the whitelist are discretionary access control (DAC) models. Hence, the whitelist is vulnerable because it only considers the target subject to be accessed, without taking into account the access rights of the file target object. In this study, we propose an industrial device security system for Windows to address this vulnerability, which improves the security of the security policy by determining not only the access rights of the subject but also those of the object through the application of the mandatory access control (MAC) policy in the Windows industrial operating system. The access control method does not base the security policy on the whitelist; instead, by investigating the setting of the security policy not only for the subject but also the object, we propose a method that provides improved stability, compared to the conventional whitelist method.

• Journal of KIISE:Software and Applications
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• v.37 no.3
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• pp.233-237
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• 2010

This paper addresses a problem of violating the member accessibility of a class in C++, which is not detected as an error by existing C++ compilers. The member access specifiers can be used to specify member accessibility. The C++ uses a private or protected specifier for specifying the members which cannot be accessed from outside of an object. However, the private or protected members can be accessed from outside of that object by the pointer arithmetic in C++. We show some violating examples that cannot be detected by existing C++ compilers. The contribution of this paper is to discover and define the new problem of the member accessibility.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.01a
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• pp.83-87
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• 2014

본 논문에서는 안드로이드 스마트폰 환경에서 높은 점유율을 가진 카카오톡 모바일 메신저 앱에 대하여 행정안전부가 고시한 Android-JAVA 시큐어 코딩가이드의 입력 데이터 검증 및 표현, API악용, 보안특성, 시간 및 상태, 에러처리, 코드 품질, 캡슐화 등 18가지 보안 취약점을 분석하고, 해당 취약점에 대한 시큐어 코딩 기법을 적용한다. 먼저 현재 상용화되고 있는 카카오톡 모바일 메신저 코드를 역공학(리버스엔지니어링)방법을 이용하여 코드단에서 소스를 분석한다. 실제 코드에서 시큐어 코딩이 안드로이드 스마트폰 환경에서 행정안전부가 고시한 Android-JAVA 시큐어 코딩가이드를 기준으로 취약한 부분을 찾고, 적용이 안 되어 있는 부분에 안드로이드 환경에 맞는 시큐어 코딩 기법을 적용한다.

• Convergence Security Journal
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• v.19 no.1
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• pp.87-95
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• 2019

The damage is increasing due to many encroachment accidents caused by increasingly sophisticated cyber attacks. Many institutions and businesses lack early response to invest a lot of resources in the infrastructure for incident detection. The initial response of an intrusion is to identify the route of attack, and many cyber attacks are targeted at software vulnerabilities. Therefore, analyzing the artifacts of a Windows system against software vulnerabilities and classifying the analyzed data can be utilized for rapid initial response. Therefore, the remaining artifacts upon entry of attacks by software are classified, and artifact grouping is presented for use in analysis of encroachment accidents.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.4
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• pp.47-62
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• 2003

Patch distribution is one of important processes to fix vulnerabilities of software and to ensure security of systems. Since an institute or a company has various operating systems or applications, it is not easy to update patches promptly. In this paper, we propose a secure patch distribution architecture with an authentication mechanism, a security assurance mechanism, a patch integrity assurance mechanism, and an automatic patch installation mechanism. We argue that the proposed architecture improve security of patch distribution processes within a domain.

• Journal of Software Assessment and Valuation
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• v.15 no.1
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• pp.115-121
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• 2019

I analyzed the structure of a block-chain system and a block-chain-based service system. It is a decentralized book encryption system software technology that does not require a third party to secure trust between the two parties. Block chains are structured in a linked list structure. The block chain manage transaction information by blocking the transaction information, in conjunction with other blocks. As a result, I have discovered structural weaknesses in current block-chain systems and block-chain-based service systems. Once these possible structural problems are resolved, I expect that the block-chain-based service system will make various industrial contributions.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.4
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• pp.79-86
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• 2016

About 75% of software security incidents are caused by software vulnerability. In addition, the after-market repairing cost of the software is higher by more than 30 times than that in the design stage. In this background, the secure coding has been proposed as one of the ways to solve this kind of maintenance problems. Various institutions have addressed the weakness patterns of the standard software. A new Korean programming language Saesark has been proposed to resolve the security weakness on the language level. However, the previous study on Saesark can not resolve the security weakness caused by the API. This paper proposes a way to resolve the security weakness due to the API. It adopts a static analyzer inspecting dangerous methods. It classifies the dangerous methods of the API into two groups: the methods of using tainted data and those accepting in-flowing tainted data. It analyses the security weakness in four steps: searching for the dangerous methods, configuring a call graph, navigating a path between the method for in-flowing tainted data and that uses tainted data on the call graph, and reporting the security weakness detected. To measure the effectiveness of this method, two experiments have been performed on the new version of Saesark adopting the static analysis. The first experiment is the comparison of it with the previous version of Saesark according to the Java Secure Coding Guide. The second experiment is the comparison of the improved Saesark with FindBugs, a Java program vulnerability analysis tool. According to the result, the improved Saesark is 15% more safe than the previous version of Saesark and the F-measure of it 68%, which shows the improvement of 9% point compared to 59%, that of FindBugs.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.5
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• pp.1191-1204
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• 2012

As attackers try to paralyze information security systems, many researchers have investigated security testing to analyze vulnerabilities of information security products. Penetration testing, a critical step in the development of any secure product, is the practice of testing a computer systems to find vulnerabilities that an attacker could exploit. Security testing like penetration testing includes gathering information about the target before the test, identifying possible entry points, attempting to break in and reporting back the findings. Therefore, to obtain maximum generality, re-usability and efficiency is very useful for efficient security testing and vulnerability hunting activities. In this paper, we propose a threat analysis based software security testing technique for evaluating that the security functionality of target products provides the properties of self-protection and non-bypassability in order to respond to attacks to incapacitate or bypass the security features of the target products. We conduct a security threat analysis to identify vulnerabilities and establish a testing strategy according to software modules and security features/functions of the target products after threat analysis to improve re-usability and efficiency of software security testing. The proposed technique consists of threat analysis and classification, selection of right strategy for security testing, and security testing. We demonstrate our technique can systematically evaluate the strength of security systems by analyzing case studies and performing security tests.