• Journal of information and communication convergence engineering
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• 제7권2호
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• pp.157-163
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• 2009

With the wide usage of internet in many fields, networks are being exposed to many security threats, such as DDoS attack and worm/virus. For enterprise network, prevention failure of network security causes the revealing of commercial information or interruption of network services. In this paper, we propose a method of prevention of DDoS attacks for enterprise network based on traceback and network traffic analysis. The model of traceback implements the detection of IP spoofing attacks by the cooperation of trusted adjacent host, and the method of network traffic analysis implements the detection of DDoS attacks by analyzing the traffic characteristic. Moreover, we present the result of the experiments, and compare the method with other methods. The result demonstrates that the method can effectively detect and block DDoS attacks and IP spoofing attacks.

• 정보보호학회논문지
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• 제27권6호
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• pp.1261-1269
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• 2017

블록 암호 설계에서 Feistel 구조는 가장 널리 사용되는 구조 중의 하나이다. 또한 Feisel 구조를 확장하여 일반화한 Feistel 구조 역시 블록 암호 뿐 아니라 해쉬 함수에서도 널리 사용되는 구조이다. Feistel 구조의 구조적 안전성에 대한 다양한 분석 및 많은 연구가 진행되었다. 이 중 최근 Feistel 구조에 대한 중간 일치 공격은 Feistel 구조의 구조적 안전성을 가장 효과적으로 분석하는 방법 중 하나이다. 본 논문에서는 일반화된 Feistel 구조에 대한 중간 일치 공격에 대한 안전성을 분석한다.

• Nuclear Engineering and Technology
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• 제51권1호
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• pp.138-145
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• 2019

With the application of digital technology to safety-critical infrastructures, cyber-attacks have emerged as one of the new dangerous threats. In safety-critical infrastructures such as a nuclear power plant (NPP), a cyber-attack could have serious consequences by initiating dangerous events or rendering important safety systems unavailable. Since a cyber-attack is conducted intentionally, numerous possible cases should be considered for developing a cyber security system, such as the attack paths, methods, and potential target systems. Therefore, prior to developing a risk-informed cyber security strategy, the importance of cyber-attacks and significant critical digital assets (CDAs) should be analyzed. In this work, an importance analysis method for cyber-attacks on an NPP was proposed using the probabilistic safety assessment (PSA) method. To develop an importance analysis framework for cyber-attacks, possible cyber-attacks were identified with failure modes, and a PSA model for cyber-attacks was developed. For case studies, the quantitative evaluations of cyber-attack scenarios were performed using the proposed method. By using quantitative importance of cyber-attacks and identifying significant CDAs that must be defended against cyber-attacks, it is possible to develop an efficient and reliable defense strategy against cyber-attacks on NPPs.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2610-2628
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• 2019

Advanced persistent threats (APTs) are constant attacks of specific targets by hackers using intelligent methods. All current internal infrastructures are constantly subject to APT attacks created by external and unknown malware. Therefore, information security officers require a framework that can assess whether information security systems are capable of detecting and blocking APT attacks. Furthermore, an on-line evaluation of information security systems is required to cope with various malicious code attacks. A regular evaluation of the information security system is thus essential. In this paper, we propose a dynamic updated evaluation framework to improve the detection rate of internal information systems for malware that is unknown to most (over 60 %) existing static information security system evaluation methodologies using non-updated unknown malware.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.595-598
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• 2014

최근의 사이버 공격은 보안패치가 발표되기 이전의 보안취약점을 악용하는 제로 데이(Zero Day) 공격, 웹 사이트를 대상으로 한 공격이 주를 이루고 있다. 이러한 공격은 소프트웨어 자체에 내장된 보안취약점을 이용하는 것이 대부분으로, 특히나 소스코드의 보안취약점을 이용한 사이버 공격은 보안장비로는 대응이 어려운 특성을 가진다. 따라서 이러한 공격을 예방하기 위해 소프트웨어를 구현하는 단계에서부터 보안취약점을 배제 시켜야한다. 본 논문에서는 구현단계에서부터 보안위협을 해소하는 Secure Coding 가이드 지원 도구를 설계하고자 한다.

• 한국IT서비스학회지
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• 제20권5호
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• pp.119-136
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• 2021

Since the global spread of COVID-19, social distancing and untact service implementation have spread rapidly. With the transition to a non-face-to-face environment such as telework and remote classes, cyber security threats have increased, and a lot of cyber compromises have also occurred. In this study, cyber-attacks and response cases related to COVID-19 are summarized in four aspects: cyber fraud, cyber-attacks on companies related to COVID-19 and healthcare sector, cyber-attacks on untact services such as telework, and preparation of untact services security for post-covid 19. After the outbreak of the COVID-19 pandemic, related events such as vaccination information and payment of national disaster aid continued to be used as bait for smishing and phishing. In the aspect of cyber-attacks on companies related to COVID-19 and healthcare sector, we can see that the damage was rapidly increasing as state-supported hackers attack those companies to obtain research results related to the COVID-19, and hackers chose medical institutions as targets with an efficient ransomware attack approach by changing 'spray and pray' strategy to 'big-game hunting'. Companies using untact services such as telework are experiencing cyber breaches due to insufficient security settings, non-installation of security patches, and vulnerabilities in systems constituting untact services such as VPN. In response to these cyber incidents, as a case of cyber fraud countermeasures, security notices to preventing cyber fraud damage to the public was announced, and security guidelines and ransomware countermeasures were provided to organizations related to COVID-19 and medical institutions. In addition, for companies that use and provide untact services, security vulnerability finding and system development environment security inspection service were provided by Government funding programs. We also looked at the differences in the role of the government and the target of security notices between domestic and overseas response cases. Lastly, considering the development of untact services by industry in preparation for post-COVID-19, supply chain security, cloud security, development security, and IoT security were suggested as common security reinforcement measures.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권11호
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• pp.2204-2220
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• 2011

Without providing a proper security measure to the handover procedure in Mobile WiMAX, several security attacks can be mounted. Even though security schemes have been previously proposed for this purpose, they are still vulnerable to several security attacks due to fatal design flaws. A newly proposed security scheme in this paper is based on the framework of authentication domain and concept of handover ticket. A method of establishing security associations within the authentication domain is proposed, and a lightweight security measure to protect the management messages associated with the handover is also proposed. Especially, using the handover ticket, the new security scheme can defend against a Redirection Attack arising from a compromised base station. The new security scheme is comparatively analyzed with the previous security schemes in terms of Replay, Session Hijacking, Man-In-The-Middle, and Redirection attacks.

• International Journal of Computer Science & Network Security
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• 제23권4호
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• pp.111-115
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• 2023

Knowledge Based Authentication is the most well-known technique for user authentication in a computer security framework. Most frameworks utilize a straightforward PIN (Personal Identification Number) or psssword as an data authenticator. Since password based authenticators typically will be software based, they are inclined to different attacks and weaknesses, from both human and software.Some of the attacks are talked about in this paper.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권8호
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• pp.3888-3910
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• 2018

As an increasing number of defense methods against control-data attacks are deployed in practice, control-data attacks have become challenging, and non-control-data attacks are on the rise. However, defense methods against non-control-data attacks are still deficient even though these attacks can produce damage as significant as that of control-data attacks. We present a method to defend against non-control-data attacks using influence domain monitoring (IDM). A definition of the data influence domain is first proposed to describe the characteristics of a variable during its life cycle. IDM extracts security-critical non-control data from the target program and then instruments the target for monitoring these variables' influence domains to ensure that corrupted variables will not be used as the attackers intend. Therefore, attackers may be able to modify the value of one security-critical variable by exploiting certain memory corruption vulnerabilities, but they will be prevented from using the variable for nefarious purposes. We evaluate a prototype implementation of IDM and use the experimental results to show that this method can defend against most known non-control-data attacks while imposing a moderate amount of performance overhead.

• 한국정보통신학회논문지
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• 제26권9호
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• pp.1374-1381
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• 2022

네트워크 공격 대응에 관한 보안기술의 기존 연구들은 하드웨어적 네트워크 보안 기술을 이용하여 네트워크의 보안성을 높이는 방법이나 바이러스 방역 백신과 바이러스 방역 시스템이 주로 제안 설계되어왔다. 많은 사용자는 라우터의 보안 기능을 충분히 활용하지 못하고 있어 이러한 문제점을 극복하기 위해 네트워크 보안 수준에 따라 분리함으로써 계층화된 보안 관리를 통하여 외부에서의 공격을 차단할 수 있음을 계층별 실험을 통해 분류하였다. 연구의 범위는 Edge 라우터의 보안기술 동향을 살펴봄으로 Edge 라우터 기반의 네트워크 공격에 관한 위협으로부터 보호하는 방법과 구현 사례를 제시한다.