• Journal of Internet Computing and Services
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• v.7 no.3
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• pp.119-132
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• 2006

The network based security techniques well-known until now have week points to be passive in attacks and susceptible to roundabout attacks so that the misuse detection based intrusion prevention system which enables positive correspondence to the attacks of inline mode are used widely. But because the Misuse detection based Intrusion prevention system is proportional to the detection rules, it causes excessive false alarm and is linked to wrong correspondence which prevents the regular network flow and is insufficient to detect transformed attacks, This study suggests an Intrusion prevention system which uses Support Vector machines(hereinafter referred to as SVM) as one of rule based Intrusion prevention system and Anomaly System in order to supplement these problems, When this compared with existing intrusion prevention system, show performance result that improve about 20% and could through intrusion prevention system that propose false positive minimize and know that can detect effectively about new variant attack.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.3
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• pp.87-96
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• 2014

Hackers try to achieve their purpose in a variety of ways, such as operating own website and hacking a website. Hackers seize a large amount of private information after they have made a zombie PC by using malicious code to upload the website and it would be used another hacking. Almost detection technique is the use Snort rule. When unknown code and the patterns in IDS/IPS devices are matching on network, it detects unknown code as malicious code. However, if unknown code is not matching, unknown code would be normal and it would attack system. Hackers try to find patterns and make shellcode to avoid patterns. So, new method is needed to detect that kinds of shellcode. In this paper, we proposed a noble method to detect the shellcode by using Shannon's information entropy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.11
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• pp.1451-1461
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• 2019

DNS spoofing is an attack in which an attacker intervenes in the communication between client and DNS server to deceive DNS server by responding to a fake IP address rather than actual IP address. It is possible to implement a pharming site that hacks user ID and password by duplicating web server's index page and simple web programming. In this paper we have studied web spoofing attack that combines DNS spoofing and pharming site implementation which leads to farming site. We have studied DNS spoofing attack method, procedure and farming site implementation method for portal server of this university. In the case of Kyungsung Portal, bypassing attack and hacking were possible even though the web server was SSL encrypted and secure authentication. Many web servers do not have security measures, and even web servers secured by SSL can be disabled. So it is necessary that these serious risks are to be informed and countermeasures are to be researched.

• 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 the Korea Institute of Information Security & Cryptology
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• v.27 no.3
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• pp.549-562
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• 2017

In recent years, as the proportion of mobile banking has become bigger with daily usage of mobile banking, security threats are also increasing according to the feeling. Accordingly, the domestic banking system introduces security solution programs in the banking application and sets security check points to ensure the stability of the application in order to check whether it is always executed. This study presents a vulnerability of inactivity bypassing mobile vaccine program operation checkpoints using the intermediate language statically and dynamically analysis when decompiling the android banking applications of major banks in Korea. Also, through the results, it identifies possible attacks that can be exploited and suggest countermeasures.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.4
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• pp.135-140
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• 2015

The WDSS improves defensive capacity against web application layer DDoS attack by using web cache server and L7 switch which are added on the DDoS shelter system. When web DDoS attack occurs, security agents divert traffic from backbone network to sub-network of the WDSS and then DDoS protection device and L7 switch block abnormal packets. In the meantime, web cache server responds only to requests of normal clients and maintains stable web service. In this way, the WDSS can counteract the web DDoS attack which generates small traffic and depletes server-client session resource. Furthermore, the WDSS does not require IP tunneling because it is not necessary to retransfer the normal requests to original web server. In this paper, we validate operation of the WDSS and verify defensive capability against web application layer DDoS attacks. In order to do this, we built the WDSS on backbone network of an ISP. And we performed web DDoS tests by using a testing system that consists of zombie PCs. The tests were performed by three types and various amounts of web DDoS attacks. Test results suggest that the WDSS can detect small traffic of the web DDoS attacks which do not have repeat flow whereas the formal DDoS shelter system cannot.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.4
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• pp.963-974
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• 2018

With the growing interest in cryptocurrency such as bitcoin, the blockchain technology has attracted much attention in various applications as a distributed security platform with excellent security. However, Cryptojacking, an attack that hijack other computer resources such as CPUs, has occured due to vulnerability to the Cryptomining process. In particular, browser-based Cryptojacking is considered serious because attacks can occur only by visiting a Web site without installing it on a visitor's PC. The current Cryptojacking detection system is mostly signature-based. Signature-based detection methods have problems in that they can not detect a new Cryptomining code or a modification of existing Cryptomining code. In this paper, we propose a Cryptojacking detection solution using a dynamic analysis-based that uses a headless browser to detect unknown Cryptojacking attacks. The proposed dynamic analysis-based Cryptojacking detection system can detect new Cryptojacking site that cannot be detected in existing signature-based Cryptojacking detection system and can detect it even if it is called or obfuscated by bypassing Cryptomining code.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.331-338
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• 2001

With the general use of network, cyber terror rages throughout the world. However, IP Fragmentation isn\`t free from its security problem yet, even though it guarantees effective transmission of the IP package in its network environment. Illegal invasion could happen or disturb operation of the system by using attack mechanism such as IP Spoofing, Ping of Death, or ICMP taking advantage of defectiveness, if any, which IP Fragmentation needs improving. Recently, apart from service refusal attack using IP Fragmentation, there arises a problem that it is possible to detour packet filtering equipment or network-based attack detection system using IP Fragmentation. In the paper, we generate the real time access log file to make the system manager help decision support and to make the system manage itself in case that some routers or network-based attack detection systems without packet reassembling function could not detect or suspend illegal invasion with divided datagrams of the packet. Through the implementation of the self-managing system we verify its validity and show its future effect.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.6
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• pp.1595-1606
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• 2018

Recently, there has been an increase in the number of social engineering techniques that indirectly attack the target system administrators or organizational weaknesses rather than the traditional technical cyber attacks that directly attacked the target systems. Accordingly, the type analysis and case study of social engineering techniques are being actively conducted. There has been, however, little effort to derive an analysis model that systematically analyzes social engineering based cyberspace operations. Therefore, this paper aims at building a Social Engineering Based Cyberspace Operations Analysis Model, which can be used as a reference framework for a case study or attack scenario generation of social engineering based cyberspace operations.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.3
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• pp.91-98
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• 2021

In most hacking attacks, hackers tend to access target systems in a variety of circumvent connection methods to hide their original IP. Therefore, finding the attacker's IP(Internet Protocol) from the defender's point of view is one of important issue to recognize hackers. If an attacker uses a proxy, original IP can be obtained through a program other than web browser in attacker's computer. Unfortunately, this method has no effect on the connection through VPN(Virtual Private Network), because VPN affects all applications. In an academic domain, various IP traceback methods using network equipments such as routers have been studied, but it is very difficult to be realized due to various problems including standardization and privacy. To overcome this limitation, this paper proposes a practical way to use client's network configuration temporarily until it can detect original IP. The proposed method does not only restrict usage of network, but also does not violate any privacy. We implemented and verified the proposed method in real internet with various VPN tools.