• Convergence Security Journal
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• v.23 no.5
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• pp.209-221
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• 2023

Due to the rapid spread of the COVID-19 virus in December 2019, the working environment was rapidly converted to telecommuting. However, since the defense industry is an organization that handles technology related to the military, the network separation policy is applied, so there are many restrictions on the application of telecommuting. Telecommuting is a global change and an urgent task considering the rapidly changing environment in the future. Currently, in order for defense companies to implement telecommuting, VPN, VDI, and network interlocking systems must be applied as essential elements. Eventually, some contact points will inevitably occur, which will increase security vulnerabilities, and strong security management is important. Therefore, in this paper, attack types are selected and threats are analyzed based on the attack tactics of the MITER ATT&CK Framework, which is periodically announced by MITER in the US to systematically detect and respond to cyber attacks. Then, by applying STRIDE threat modeling, security threats are classified and specific security requirements are presented.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.3
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• pp.465-479
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• 2020

Regardless of the domestic and foreign governments/companies, SOC (Security Operation Center) has operated 24 hours a day for the entire year to ensure the security for their IT infrastructures. However, almost all SOCs have a critical limitation by nature, caused from heavily depending on the manual analysis of human agents with the text-based monitoring architecture. Even though, in order to overcome the drawback, technologies for a comprehensive visualization against complex cyber threats have been studying, most of them are inappropriate for the security monitoring in large-scale networks. In this paper, to solve the problem, we propose a novel visual approach for intuitive threats monitoring b detecting suspicious IP address, which is an ultimate challenge in cyber security monitoring. The approach particularly makes it possible to detect, trace and analysis of suspicious IPs statistically in real-time manner. As a result, the system implemented by the proposed method is suitably applied and utilized to the real-would environment. Moreover, the usability of the approach is verified by successful detecting and analyzing various attack IPs.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.12
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• pp.471-480
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• 2016

Recently, the damage of cyber attack toward infra-system, national defence and security system is gradually increasing. In this situation, military recognizes the importance of cyber warfare, and they establish a cyber system in preparation, regardless of the existence of threaten. Thus, the study of Intrusion Detection System(IDS) that plays an important role in network defence system is required. IDS is divided into misuse and anomaly detection methods. Recent studies attempt to combine those two methods to maximize advantagesand to minimize disadvantages both of misuse and anomaly. The combination is called Hybrid IDS. Previous studies would not be inappropriate for near real-time network environments because they have computational complexity problems. It leads to the need of the study considering the structure of IDS that have high detection rate and low computational cost. In this paper, we proposed a Hybrid IDS which combines C4.5 decision tree(misuse detection method) and Weighted K-means algorithm (anomaly detection method) hierarchically. It can detect malicious network packets effectively with low complexity by applying mutual information and genetic algorithm based efficient feature selection technique. Also we construct upgraded the the hierarchical structure of IDS reusing feature weights in anomaly detection section. It is validated that proposed Hybrid IDS ensures high detection accuracy (98.68%) and performance at experiment section.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.669-676
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• 2017

Recently, due to the importance of information security, security vulnerability analysis and various information protection technologies and security systems are being introduced as a countermeasure against cyber-attacks in new as well as existing buildings, and information security studies on high-rise buildings are also being conducted. However, security system introduction and research are generally performed from the viewpoint of general IT systems and security policies, so there is little consideration of the infrastructure of the building. In particular, the BAS or building infrastructure, is a closed system, unlike typical IT systems, but has unique structural features that accommodate open functions. Insufficient understanding of these system structures and functions when establishing a building security policy makes the information security policies for the BAS vulnerable and increases the likelihood that all of the components of the building will be exposed to malicious cyber-attacks via the BAS. In this paper, we propose an architecture reference model that integrates three different levels of BAS structure (from?) different vendors. The architectures derived from this study and the security characteristics and vulnerabilities at each level will contribute to the establishment of security policies that reflect the characteristics of the BAS and the improvement of the safety management of buildings.

• Korean Journal of Artificial Intelligence
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• v.11 no.2
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• pp.39-44
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• 2023

The creativity of thesis is that the significance of cyber security challenges in blockchain. The variety of enterprises, including those in the medical market, are the targets of cyberattacks. Hospitals and clinics are only two examples of medical facilities that are easy targets for cybercriminals, along with IoT-based medical devices like pacemakers. Cyberattacks in the medical field not only put patients' lives in danger but also have the potential to expose private and sensitive information. Reviewing and looking at the present and historical flaws and vulnerabilities in the blockchain-based IoT and medical institutions' equipment is crucial as they are sensitive, relevant, and of a medical character. This study aims to investigate recent and current weaknesses in medical equipment, of blockchain-based IoT, and institutions. Medical security systems are becoming increasingly crucial in blockchain-based IoT medical devices and digital adoption more broadly. It is gaining importance as a standalone medical device. Currently the use of software in medical market is growing exponentially and many countries have already set guidelines for quality control. The achievements of the thesis are medical equipment of blockchain-based IoT no longer exist in a vacuum, thanks to technical improvements and the emergence of electronic health records (EHRs). Increased EHR use among providers, as well as the demand for integration and connection technologies to improve clinical workflow, patient care solutions, and overall hospital operations, will fuel significant growth in the blockchain-based IoT market for linked medical devices. The need for blockchain technology and IoT-based medical device to enhance their health IT infrastructure and design and development techniques will only get louder in the future. Blockchain technology will be essential in the future of cybersecurity, because blockchain technology can be significantly improved with the cybersecurity adoption of IoT devices, i.e., via remote monitoring, reducing waiting time for emergency rooms, track assets, etc. This paper sheds the light on the benefits of the blockchain-based IoT market.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.5132-5148
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• 2017

Cyber attacks are evolving commensurate with recent developments in information security technology. Intrusion detection systems collect various types of data from computers and networks to detect security threats and analyze the attack information. The large amount of data examined make the large number of computations and low detection rates problematic. Feature selection is expected to improve the classification performance and provide faster and more cost-effective results. Despite the various feature selection studies conducted for intrusion detection systems, it is difficult to automate feature selection because it is based on the knowledge of security experts. This paper proposes a feature selection technique to overcome the performance problems of intrusion detection systems. Focusing on feature selection, the first phase of the proposed system aims at constructing a feature subset using a sequential forward floating search (SFFS) to downsize the dimension of the variables. The second phase constructs a classification model with the selected feature subset using a random forest classifier (RFC) and evaluates the classification accuracy. Experiments were conducted with the NSL-KDD dataset using SFFS-RF, and the results indicated that feature selection techniques are a necessary preprocessing step to improve the overall system performance in systems that handle large datasets. They also verified that SFFS-RF could be used for data classification. In conclusion, SFFS-RF could be the key to improving the classification model performance in machine learning.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.4
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• pp.953-960
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• 2016

Due to the prevalent use of online systems and the increasing amount of accessible information, the influence of recommender systems is growing bigger than ever. However, there are several attempts by malicious users who try to compromise or manipulate the reliability of recommender systems with cyber-attacks. By analyzing the ratio of 'sympathy' against 'apathy' responses about a concerned review and reflecting the results in a recommendation system, we could present a way to improve the performance of a recommender system and maintain a robust system. After collecting and applying actual movie review data, we found that our proposed recommender system showed an improved performance compared to the existing recommendation systems.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.6
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• pp.1607-1620
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• 2015

The server privilege account must be operated through law and regulation. However, due to regulation non-compliance and inadequate operation on financial company server privilege, an incident that every server data being deleted by hacker occur which is later being named as 'NH Bank Cyber Attack'. In this paper, the current operation status on financial company privilege accounts is being analysed to elicit problems and improvement. From the analysis, important evaluation factors will be also selected and applied generating the decision making model for financial company server privilege account operation. The evaluation factor deducted from privilege account status analysis will be used to present and verify the decision making model and formula through AHP(Analytic Hierarchy process).

• IEIE Transactions on Smart Processing and Computing
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• v.1 no.1
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• pp.65-71
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• 2012

Mobile RFID is a new application that uses a mobile phone as an RFID reader with wireless technology and provides a new valuable service to users by integrating RFID and ubiquitous sensor network infrastructures with mobile communication and wireless Internet. Whereas the mobile RFID system has many advantages, privacy violation problems on the reader side are very concerning to individuals and researchers. Unlike in regular RFID environments, where the communication channel between the server and reader is assumed to be secure, the communication channel between the backend server and the RFID reader in the mobile RFID system is not assumed to be safe. Therefore it has become necessary to devise a new communication protocol that secures the privacy of mobile RFID-enabled devices. Recently, Lo et al. proposed a mutual key agreement protocol that secures the authenticity and privacy of engaged mobile RFID readers by constructing a secure session key between the reader and server. However, this paper shows that this protocol does not meet all of the necessary security requirements. Therefore we developed an enhanced mutual key agreement protocol for mobile RFID-enabled devices that alleviates these concerns. We further show that our protocol can enhance data security and provide privacy protection for the reader in an unsecured mobile RFID environment, even in the presence of an active adversary.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4529-4548
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• 2016

DDoS attacks have had a devastating effect on the Internet, which can cause millions of dollars of damage within hours or even minutes. In this paper we propose a practical dynamic defense approach that overcomes the shortage of static defense mechanisms. Our approach employs a group of SDN-based proxy switches to relay data flow between users and servers. By substituting backup proxy switches for attacked ones and reassigning suspect users onto the new proxy switches, innocent users are isolated and saved from malicious attackers through a sequence of remapping process. In order to improve the speed of attacker segregation, we have designed and implemented an efficient greedy algorithm which has been demonstrated to have little influence on legitimate traffic. Simulations, which were then performed with the open source controller Ryu, show that our approach is effective in alleviating DDoS attacks and quarantining the attackers by numerable remapping process. The simulations also demonstrate that our dynamic defense imposes little effect on legitimate users, and the overhead introduced by remapping procedure is acceptable.