• The Journal of the Korea Contents Association
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• v.21 no.1
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• pp.284-291
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• 2021

As the current security monitoring system is operated as a passive system only for response after an attacker's attack, it is common to respond to intrusion incidents after an attack occurs. In particular, when new assets are added and actual services are performed, there is a limit to vulnerability testing and pre-defense from the point of view of an actual hacker. In this paper, a new security monitoring model has been proposed that uses multiple hacking-related search engines to add proactive vulnerability response functions of protected assets. In other words, using multiple search engines with general purpose or special purpose, special vulnerabilities of the assets to be protected are checked in advance, and the vulnerabilities of the assets that have appeared as a result of the check are removed in advance. In addition, the function of pre-checking the objective attack vulnerabilities of the protected assets recognized from the point of view of the actual hacker, and the function of discovering and removing a wide range of system-related vulnerabilities located in the IP band in advance were additionally presented.

• 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.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.6
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• pp.89-98
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• 2007

We have come a long way in the information age. Thanks to the advancement of such technologies as the internet, we have discovered new ways to convey information on a broader scope. However, negative aspects exist as is with anything else. These may include invasion of privacy over the web, or identity theft over the internet. What is more alarming is that malwares so called 'maliciouscodes' are rapidly spreading. Its intent is very destructive which can result in hacking, phishing and as aforementioned, one of the most disturbing problems on the net, invasion of privacy. This thesis describes the technology of how you can effectively analyze and detect these kind of malicious codes. We propose sequencial hybrid analysis for API calls that are hooked inside user-mode and kernel-level of Windows. This research explains how we can cope with malicious code more efficiently by abstracting malicious function signature and hiding attribute.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.4
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• pp.143-152
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• 2008

The incredible progress of information and communication technology has allowed various information and communication services to emerge in the Web environment. Such a service is initiated when the user provides his/her personal information to the service provider and is then given an identifier and authentication data. A series of the processes is inconvenient as it requires authentication by the service provider each time that the user requests the service. Furthermore, as the user subscribes to more services, the volume of ID and authentication information increases. This compels the users to use an ID that is easy to remember or to register the same ID over and over, increasing the risk of ID hacking. It is clear that such threats will become more serious as our lives become more dependent upon the Internet and as the Internet service environment advances. With the introduction of different services, the need to efficiently manage ID has been raised. In this paper, a Internet Identity Management Service that enables the control of the flow of the user’s personal information, which is used and stored for the Internet service, is proposed from the user's perspective.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.1
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• pp.73-81
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• 2021

When downloading files using an app or web-based application on the user's mobile phone, the path is set to be saved in the pre-defined default directory. Many applications requiring access to storage, including file managers, require a write or read permission of storage to provide numerous functions and services. This means that the application will have direct access to the download folder where the numerous files downloaded. In this paper, to prove our feasibility of attack using the security vulnerabilities mentioned above, we developed a file hacking function disguised as an encryption function in the file management application. The file that encrypted will be sent to hackers via E-mail simultaneously on the background. The developed application was evaluated from VirusTotal, a malicious analysis engine, was not detected as a malicious application in all 74 engines. Finally, in this paper, we propose a defense technique and an algorithm based on the Trusted Execution Environment (TEE) to supplement these storage vulnerabilities.

• Convergence Security Journal
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• v.23 no.4
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• pp.33-41
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• 2023

In recent years, advanced persistent threat (APT) attack organizations have exploited various vulnerabilities and attack techniques to target companies and institutions with national core technologies, distributing ransomware and demanding payment, stealing nationally important industrial secrets and distributing them on the black market (dark web), selling them to third countries, or using them to close the technology gap, requiring national-level security preparations. In this paper, we analyze the attack methods of attack organizations such as Kimsuky and Lazarus that caused industrial secrets leakage damage through APT attacks in Korea using the MITRE ATT&CK framework, and derive 26 cybersecurity-related administrative, physical, and technical security requirements that a company's security system should be equipped with. We also proposed a security framework and system configuration plan to utilize the security requirements in actual field. The security requirements presented in this paper provide practical methods and frameworks for security system developers and operators to utilize in security work to prevent leakage of corporate industrial secrets. In the future, it is necessary to analyze the advanced and intelligent attacks of various APT attack groups based on this paper and further research on related security measures.

• The KIPS Transactions:PartC
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• v.10C no.6
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• pp.683-694
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• 2003

We present X-tree Diff, a change detection algorithm for tree-structured data. Our work is motivated by need to monitor massive volume of web documents and detect suspicious changes, called defacement attack on web sites. From this context, our algorithm should be very efficient in speed and use of memory space. X-tree Diff uses a special ordered labeled tree, X-tree, to represent XML/HTML documents. X-tree nodes have a special field, tMD, which stores a 128-bit hash value representing the structure and data of subtrees, so match identical subtrees form the old and new versions. During this process, X-tree Diff uses the Rule of Delaying Ambiguous Matchings, implying that it perform exact matching where a node in the old version has one-to one corrspondence with the corresponding node in the new, by delaying all the others. It drastically reduces the possibility of wrong matchings. X-tree Diff propagates such exact matchings upwards in Step 2, and obtain more matchings downwsards from roots in Step 3. In step 4, nodes to ve inserted or deleted are decided, We aldo show thst X-tree Diff runs on O(n), woere n is the number of noses in X-trees, in worst case as well as in average case, This result is even better than that of BULD Diff algorithm, which is O(n log(n)) in worst case, We experimented X-tree Diff on reat data, which are about 11,000 home pages from about 20 wev sites, instead of synthetic documets manipulated for experimented for ex[erimentation. Currently, X-treeDiff algorithm is being used in a commeercial hacking detection system, called the WIDS(Web-Document Intrusion Detection System), which is to find changes occured in registered websites, and report suspicious changes to users.

• Korean Security Journal
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• no.62
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• pp.9-33
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• 2020

This study presents aspects of the financing of terrorism using virtual-currencies. Fisrt of all, this introduces the conventional threat of the financing of terrorism and the analysis of current legal system regarding virtual-currency in South Korea. Next, the financing of terrorism cases are analyzed. With given analysis, the paper deals with its response and future extensions by technical and institutional aspects. The threats of the financing of terrorism are going higher after the appearance of virtual-currencies such as Bitcoin. There are two typical ways to use virtual-currencies by terrorist groups. One is to conduct public fund-raising in the social network system and the dark web. The other is to hack into virtual-currency exchange network in order to steal virtual currencies for developing the weapon of mass destruction. Specifically South Korea is top three country of trading virtual currencies and has been subject to virtual-currency hacking more than 10 cases. However, many countries including South Korea deal with virtual currencies as only innovative technology and means of investment, not the threats of the financing of terrorism. Under these circumstances, there a the legal contradiction. This article points this limit and absurdity. Also, it shows reasonable alternatives. All in all, given these aspects, the article proposes detailed policy directions.