• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.523-525
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• 2002

DOS (Denial Of Service)에 대한 공격은 시스템의 정상적인 동작을 방해하여 시스템 사용자에 대한 서비스 제공을 거부하도록 만드는 공격으로 현재 이의 공격에 대한 탐지 알고리즘 및 연구들이 많이 제시되고 있다. 본 논문에서는 네트워크 또는 트랜스포트 계층에 해당하는 프로토콜(TCP/IP, ICMP, UDP) 공격을 분석하고 이들 프로토콜의 취약점을 공격하는 DOS 공격 이외의 다른 공격을 탐지하기 위하여 프로토콜의 기능별, 계층별에 따른 모듈화 작업을 통하여 네트워크 침입탐지 시스템을 설계하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.637-639
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• 2003

인터넷이 널리 보급되면서 이용자들간에는 편리하고 빠른 정보교환이 가능하게 되었지만 이를 방해하는 해커들의 활동 또한 크게 증가하고 있다. 그 중 DDoS(Distributed Denial of Service) 공격은 인터넷 서비스를 하고 있는 서버에 심각한 해를 주며 탐지와 대응이 어려운 해킹방법중의 하나이다. 본 연구에서는 DDoS 공격 대응을 위해 액티브 네트워크를 이용해 개발한 DDoS 보안시스템[1][2]을 이용할 때 얼마나 효과적인 성능을 낼 수 있는지에 대한 분석 결과를 제공한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.302-304
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• 2003

최근 인터넷을 통하여 급속히 확산되고 있는 분산 서비스 거부 공격은 전 세계 웹 사이트들에 큰 피해를 입히면서 세계적인 문제로 부상되었다. 현재 이에 대한 대책으로 방화벽이나 침입 탐지 시스템을 이용하지만. 전 세계에서 동시 다발적으로 일어나는 이 공격을 근본적으로 방지하는 데는 적합지 않다. 이에 본 논문에서는 공격 트래픽의 송신자 주소를 임의의 IP 주소를 사용하여 공격의 발원지를 추적할 수 없는 기존 문제점을 해결할 수 있는 분산 서비스 거부 공격 발원지 자동 추적 모델을 제시하고자 한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2000.11a
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• pp.525-529
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• 2000

본 논문에서는 최근 네트웍을 통해 실질적인 관리자가 권한을 획득할 수 있는 공격기법을 살펴보고 그에 따른 대처 방안을 모색한다. 또한 Yahoo, CNN뿐만 아니라 최근 정부 및 교육기관 등에까지 막심한 피해를 입히고 있는 서비스 거부 공격(Denial of Service Attack) 각각의 공격 원리와 방어 방안을 고려하고, 악의적인 서버가 침입차단시스템을 회피하여 원격지의 클라이언트와 데이터를 송·수신할 수 있는 최근의 공격 기법을 소개한다.

• Journal of the Korea Society for Simulation
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• v.18 no.4
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• pp.39-47
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• 2009

Recently, the threat of DDoS attacks is increasing and many companies are planned to deploy the DDoS defense solutions in their networks. The DDoS attack usually transmits heavy traffic data to networks or servers and they cannot handle the normal service requests because of running out of resources. Since it is very hard to prevent the DDoS attack beforehand, the strategic plan is very important. In this work, we have conducted modeling and simulation of the DDoS attack by changing the number of servers and estimated the duration that services are available. In this work, the modeling and simulation is conducted using OPNET Modeler. The simulation result can be used as a parameter of trade-off analysis of DDoS defense cost and the service's value. In addition, we have presented a way of estimating the cost effectiveness in deployment of the DDoS defense system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.143-145
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• 2022

With the spread of the Internet around the world, devices connected to the Internet are gradually increasing. In addition, the number of distributed reflection service attacks (DrDoS), an attack that maliciously requests large responses by deceiving IPs as if the attacker was a victim, using vulnerabilities in application protocols such as DNS, NTP, and CLDAP, is increasing rapidly. It is believed that the security threat of distributed reflection service attacks will not disappear unless ISPs establish appropriate countermeasures to IP Spoofing. Therefore, this paper describes the security threat and response status of distributed reflection service attacks based on IP Spoofing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8C
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• pp.741-747
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• 2002

In this paper, we present a new form of DDOS attack and a mechanism to defend systems from it. Up to now the ultimate target of a DDOS attack is a specific host. But in the near future router attacks are expected to appear. Because these kinds of attacks may involve many hosts in the managed domain of a specific router, they will be still more serious than the current DDOS attacks. Also, we present an algorithm to defend against an attack on a router using survivability of the router. By using a survivability of a router, the router can control a quantity of traffic autonomously without an interruption of services even when a DDOS attack occurs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1374-1381
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• 2022

Existing research on security technology related to network attack response has focused on research using hardware network security technology, network attacks that wiretap and wiretap network packets, denial of service attack that consumes server resources to bring down the system, and network by identifying vulnerabilities before attack. It is classified as a scanning attack. In addition, methods for increasing network security, antivirus vaccines and antivirus systems have been mainly proposed and designed. In particular, many users do not fully utilize the security function of the router. In order to overcome this problem, it is classified according to the network security level to block external attacks through layered security management through layer-by-layer experiments. The scope of the study was presented by examining the security technology trends of edge routers, and suggested methods and implementation examples to protect from threats related to edge router-based network attacks.

• Journal of the Korea Society of Computer and Information
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• v.21 no.7
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• pp.1-8
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• 2016

Nowadays, distributed denial of service (DDoS) attacks on web sites reward attackers financially or politically because our daily lifes tightly depends on web services such as on-line banking, e-mail, and e-commerce. One of DDoS attacks to web servers is called HTTP-GET flood attack which is becoming more serious. Most existing techniques are running on the application layer because these attack packets use legitimate network protocols and HTTP payloads; that is, network-level intrusion detection systems cannot distinguish legitimate HTTP-GET requests and malicious requests. In this paper, we propose a practical detection technique against HTTP-GET flood attacks, based on the access behavior of inline objects in a webpage using NetFlow data. In particular, our proposed scheme is working on the network layer without any application-specific deep packet inspections. We implement the proposed detection technique and evaluate the ability of attack detection on a simple test environment using NetBot attacker. Moreover, we also show that our approach must be applicable to real field by showing the test profile captured on a well-known e-commerce site. The results show that our technique can detect the HTTP-GET flood attack effectively.

• Journal of Korea Multimedia Society
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• v.18 no.1
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• pp.35-41
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• 2015

SDN(Software Defined Networking) has been considered as a new future computer network architecture and DDoS(Distributed Denial of Service) is the biggest threat in the network security. In SDN architecture, we present the technique to defend the DDoS SYN Flooding attack that is one of the DDoS attack method. First, we monitor the Backlog queue in order to reduce the unnecessary monitoring resources. If the Backlog queue of the certain server is occupied over 70%, the sFlow performs packet sampling with the server address as the destination address. To distinguish between the attacker and the normal user, we use the source address. We decide the SYN packet threshold using the remaining Backlog queue that possible to allow the number of connections. If certain sources address send the SYN packet over the threshold, we judge that this address is attacker. The controller will modify the flow table entry to block attack traffics. By using this method, we reduce the resource consumption about the unnecessary monitoring and the protection range is expanded to all switches. The result achieved from our experiment show that we can prevent the SYN Flooding attack before the Backlog queue is fully occupied.