• Journal of the Korea Society of Computer and Information
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• v.24 no.5
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• pp.27-33
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• 2019

One of serious security threats is a botnet-based attack. A botnet in general consists of numerous bots, which are computing devices with networking function, such as personal computers, smartphones, or tiny IoT sensor devices compromised by malicious codes or attackers. Such botnets can launch various serious cyber-attacks like DDoS attacks, propagating mal-wares, and spreading spam e-mails over the network. To establish a botnet, attackers usually inject malicious URLs into web source codes stealthily by using data hiding methods like Javascript obfuscation techniques to avoid being discovered by traditional security systems such as Firewall, IPS(Intrusion Prevention System) or IDS(Intrusion Detection System). Meanwhile, it is non-trivial work in practice for software developers to manually find such malicious URLs which are hidden in numerous web source codes stored in web servers. In this paper, we propose a security defense system to discover such suspicious, malicious URLs hidden in web source codes, and present experiment results that show its discovery performance. In particular, based on our experiment results, our proposed system discovered 100% of URLs hidden by Javascript encoding obfuscation within sample web source files.

• International Journal of Computer Science & Network Security
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• v.22 no.3
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• pp.155-162
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• 2022

Over the last 10 years, there has been rapid growth in the use of Machine Learning (ML) techniques to automate the process of intrusion threat detection at a scale never imagined before. This has prompted researchers, software engineers, and network specialists to rethink the applications of machine ML techniques particularly in the area of cybersecurity. As a result there exists numerous research documentations on the use ML techniques to detect and block cyber-attacks. This article is a systematic review involving the identification of published scholarly articles as found on IEEE Explore and Scopus databases. The articles exclusively related to the use of machine learning in Intrusion Detection Systems (IDS). Methods, concepts, results, and conclusions as found in the texts are analyzed. A description on the process taken in the identification of the research articles included: First, an introduction to the topic which is followed by a methodology section. A table is used to list identified research articles in the form of title, authors, methodology, and key findings.

• Korean Security Journal
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• no.39
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• pp.319-353
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• 2014

Cyber-based technologies are now ubiquitous around the glob and are emerging as an "instrument of power" in societies, and are becoming more available to a country's opponents, who may use it to attack, degrade, and disrupt communications and the flow of information. The globe-spanning range of cyberspace and no national borders will challenge legal systems and complicate a nation's ability to deter threats and respond to contingencies. Through cyberspace, competitive powers will target industry, academia, government, as well as the military in the air, land, maritime, and space domains of our nations. Enemies in cyberspace will include both states and non-states and will range from the unsophisticated amateur to highly trained professional hackers. In much the same way that airpower transformed the battlefield of World War II, cyberspace has fractured the physical barriers that shield a nation from attacks on its commerce and communication. Cyberthreats to the infrastructure and other assets are a growing concern to policymakers. In 2013 Cyberwarfare was, for the first time, considered a larger threat than Al Qaeda or terrorism, by many U.S. intelligence officials. The new United States military strategy makes explicit that a cyberattack is casus belli just as a traditional act of war. The Economist describes cyberspace as "the fifth domain of warfare and writes that China, Russia, Israel and North Korea. Iran are boasting of having the world's second-largest cyber-army. Entities posing a significant threat to the cybersecurity of critical infrastructure assets include cyberterrorists, cyberspies, cyberthieves, cyberwarriors, and cyberhacktivists. These malefactors may access cyber-based technologies in order to deny service, steal or manipulate data, or use a device to launch an attack against itself or another piece of equipment. However because the Internet offers near-total anonymity, it is difficult to discern the identity, the motives, and the location of an intruder. The scope and enormity of the threats are not just focused to private industry but also to the country's heavily networked critical infrastructure. There are many ongoing efforts in government and industry that focus on making computers, the Internet, and related technologies more secure. As the national intelligence institution's effort, cyber counter-intelligence is measures to identify, penetrate, or neutralize foreign operations that use cyber means as the primary tradecraft methodology, as well as foreign intelligence service collection efforts that use traditional methods to gauge cyber capabilities and intentions. However one of the hardest issues in cyber counterintelligence is the problem of "Attribution". Unlike conventional warfare, figuring out who is behind an attack can be very difficult, even though the Defense Secretary Leon Panetta has claimed that the United States has the capability to trace attacks back to their sources and hold the attackers "accountable". Considering all these cyber security problems, this paper examines closely cyber security issues through the lessons from that of U.S experience. For that purpose I review the arising cyber security issues considering changing global security environments in the 21st century and their implications to the reshaping the government system. For that purpose this study mainly deals with and emphasis the cyber security issues as one of the growing national security threats. This article also reviews what our intelligence and security Agencies should do among the transforming cyber space. At any rate, despite of all hot debates about the various legality and human rights issues derived from the cyber space and intelligence service activity, the national security should be secured. Therefore, this paper suggests that one of the most important and immediate step is to understanding the legal ideology of national security and national intelligence.

• Korean Security Journal
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• no.54
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• pp.9-35
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• 2018

During the recent years, cyber attacks have been increasing both in the private sector and the government. Those include the DDOS cases in 2009, the Blue House cyber attack, bank hackings etc. Cyber threats are becoming increasingly serious. However, there is no basic law related to cyber security at present, and regulations related to cyber security are scattered in various domestic laws. This can lead to confusion in the application of the law and difficult to grasp the regulations related to cyber security. In order to overcome this situation, the bill on the prevention and countermeasures against cyber crisis was initiated in 2006, but it has been abrogated. Since then, it has been repeatedly proposed, but it has been abrogated repeatedly due to the overlapping of existing laws and concerns about infringement of personal information. The most recent initiative was the National Cyber Security Act, which was initiated by the government in January 2017. The act focuses on resolving the absence of a basic law related to cyber security, strengthening its responsiveness in the event of a cyber security crisis, and fostering security strength. Therefore, this study seeks to contribute to the establishment of National Cyber Security legislation as a basic law of cyber security by examining the necessity of National Cyber Security legislation through comparative legal analysis with existing domestic laws related to cyber security and suggesting policy implications.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.2
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• pp.65-73
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• 2014

An overall responding security-centered framework is necessary required for infringement accidents, failures, and cyber threats. On the other hand, the correspondence structures of existing administrative, technical, physical security have weakness in a system responding to complex attacks because each step is performed independently. This study will recognize all internal and external users as a potentially threatening element. To perform connectivity analysis regarding an action, an intelligent convergence security framework and road map is suggested. A suggested convergence security framework was constructed to be independent of an automatic framework, such as the conventional single solution for the priority defense system of APT of the latest attack type, which makes continuous reputational attacks to achieve its goals. This study suggested the next generation convergence security framework to have preemptive responses, possibly against an APT attack, consisting of the following five hierarchical layers: domain security, domain connection, action visibility, action control, and convergence correspondence. In the domain, the connection layer suggests a security instruction and direction in the domains of administrative, physical and technical security. The domain security layer has consistency of status information among the security domain. A visibility layer of an intelligent attack action consists of data gathering, comparison and decision cycle. The action control layer is a layer that controls the visibility action. Finally, the convergence corresponding layer suggests a corresponding system of before and after an APT attack. The administrative security domain had a security design based on organization, rule, process, and paper information. The physical security domain is designed to separate into a control layer and facility according to the threats of the control impossible and control possible. Each domain action executes visible and control steps, and is designed to have flexibility regarding security environmental changes. In this study, the framework to address an APT attack and load map will be used as an infrastructure corresponding to the next generation security.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.12
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• pp.1786-1793
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• 2022

Cyber-attacks such as smishing and hacking mail exploiting COVID-19, political and social issues, have recently been continuous. Machine learning and deep learning technology research are conducted to prevent any damage due to cyber-attacks inducing malicious links to breach personal data. It has been concluded as a lack of basis to judge the attacks to be malicious in previous studies since the features of data set were excessively simple. In this paper, nine main features of three types, "URL Days", "URL Word", and "URL Abnormal", were proposed in addition to lexical features of URL which have been reflected in previous research. F1-Score and accuracy index were measured through four different types of machine learning algorithms. An improvement of 0.9% in a result and the highest value, 98.5%, were examined in F1-Score and accuracy through comparatively analyzing an existing research. These outcomes proved the main features contribute to elevating the values in both accuracy and performance.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.4
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• pp.905-917
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• 2018

The sovereign state has the right to engage in self-defense or war with the approval of the Security Council when it receives an invasion of territory from a foreign country. War is conducted under the principle of the necessity and proportionality of self-defense. In case of cyber attack, proportional countermeasure must be made through attack means and effect analysis, and cyber weapons need to be classified for this purpose. Therefore, this study aims to provide a rational and legitimate response according to the necessity and proportionality of the self - defense right by suggesting definition and classification criteria of cyber weapons. In this study, cyber weapons were defined as "means of collecting, attacking, and protecting information using cyber technology in the cyber space according to military objectives. Based on existing weapon systems and public cyber weapons cases, cyber weapons were classified as (1) cyber weapons for information gathering, (2) cyber weapons for attack, and (3) cyber weapons for protection. We suggest the considerations for applying the proportional response according to this functional classification. In order to guarantee the principle of proportionality to cyber attacks in the future, the classification study based on the cyber weapon effect should be conducted. This study has conducted an exploratory study on the classification of cyber clusters which constitutes one axis of the proportionality principle.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.3
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• pp.31-38
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• 2010

It has become more difficult to correspond an cyber attack quickly as patterns of attack become various and complex. However, current security mechanisms just have passive defense functionalities. In this paper, we propose new network security architecture to respond various cyber attacks rapidly and to chase and isolate the attackers through cooperation between security zones. The proposed architecture makes it possible to deal effectively with cyber attacks such as IP spoofing or DDoS(Distributed Denial of Service), by using active packet technology including a mobile code on active network. Also, it is designed to have more active correspondent than that of existing mechanisms. We implemented these mechanisms in Linux routers and experimented on a testbed to verify realization possibility of attacker response framework using mobile code. The experimentation results are analyzed.

• Convergence Security Journal
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• v.11 no.6
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• pp.67-72
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• 2011

A system that provides a ubiquitous service is a networked system that has to overcome their circumstances that the service survivability is weak. the survivability of a networked system is defined as an ability of the system that can offer their services without interruption, regardless of whether components comprising the system are under failures, crashes, or physical attacks. This paper presents an approach that end users can obtain a quantitative evaluation of U-service survivability to reflect intended cyber attacks causing the networked system to fall into byzantine failures in addition to the definition of the survivability. In this paper, a Jini system based on wireless local area networks is used as an example for quantitative evaluation of U-service survivability. This paper also presents an continuous time markov chain (CTMC) Model for evaluation of survivability of U-service that a Jini system provides, and an approach to evaluate the survivability of the U-service as a blocking probability that end users can not access U-services.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.959-970
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• 2004

It has become more difficult to correspond an cyber attack quickly as patterns of attack become various and complex. However, current so curity mechanisms just have passive defense functionalities. In this paper, we propose new network suity architecture to respond various cyber attacks rapidly and to chase and isolate the attackers through cooperation between security zones. The proposed architecture makes it possible to deal effectively with cyber attacks such as IP spoofing or DDoS(Distributed Denial of Service), by using active packet technology including a mobile code on active network. Also, it is designed to have more active correspondent than that of existing mechanisms. We im-plemented these mechanisms in Linux routers and experimented on a testbed to verify realization possibility of attacker response framework using mobile code. The experimentation results are analyzed.