• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.732-742
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• 2016

This study suggests methods of defense against low-level high-bandwidth DDoS attacks by adding a solution with a time limit factor (TLF) to an existing high-bandwidth DDoS defense system. Low-level DDoS attacks cause faults to the service requests of normal users by acting as a normal service connection and continuously positioning the connected session. Considering this, the proposed method makes it possible for users to show a down-related session by considering it as a low-level DDoS attack if the abnormal flow is detected after checking the amount of traffic. However, the service might be blocked when misjudging a low-level DDoS attack in the case of a communication fault resulting from a network fault, even with a normal connection status. Thus, we made it possible to reaccess the related information through a certain period of blocking instead of a drop through blacklist. In a test of the system, it was unable to block the session because it recognized sessions that are simply connected with a low-level DDoS attack as a normal communication.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.1-7
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• 2012

DDoS attack is a malicious attempt to exhaust resources of target system and network capacities using lots of distributed zombi systems. DDoS attack introduced in early 2000 has being evolved over time and presented in a various form of attacks. This paper proposes a scheme to detect DDoS attacks and to reduce possibility of such attacks that are especially based on vulnerabilities presented by using control packets of existing network protocols. To cope with DDoS attacks, the proposed scheme utilizes a buffer management techniques commonly used for congestion control in Internet. Our scheme is not intended to detect DDoS attacks perfectly but to minimize possibility of overloading of internal system and to mitigate possibility of attacks by discarding control packets at the time of detecting DDoS attacks. In addition, the detection module of our scheme can adapt dynamically to instantly increasing traffic unlike previously proposed schemes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.375-378
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• 2009

DDoS attacks make people can't using normal internet service, because DDoS attacks cause exhaustion of network bandwidth or exhaustion of computer system resources by using many personal computers or servers which already infected computer virus from hackers. Recent DDoS attacks attack government brach, financial institution, even IT security company. IT security companies make Anti-DDoS product for defense from DDoS attack. But, There is no standard for BMT of Anti-DDoS product. In this dissertation, Anti-DDoS product quality characteristics of the survey analysis to evaluate them by comparing the assessment items were derived.

• Convergence Security Journal
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• v.13 no.1
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• pp.79-86
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• 2013

The objective of DDoS Attacks is to simply disturb the services. In recent years, the DDoS attacks have been evolved into Multi-Vector Attacks which use diversified and mixed attacking techniques. Multi-Vector Attacks start from DDoS Attack and Malware Infection, obtain inside information, and make zombie PC to reuse for the next DDoS attacks. These forms of Multi-Vector Attacks are unable to be prevented by the existing security strategies for DDoS Attacks and Malware Infection. This paper presents an approach to effectively defend against diversified Multi-Vector attacks by using Reverse Proxy Group and PMS(Patch Management Server).

• Journal of KIISE
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• v.43 no.5
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• pp.596-605
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• 2016

Since the Denial of Service Attack against multiple targets in the Korean network in private and public sectors in 2009, Korea has spent a great amount of its budget to build strong Internet infrastructure against DDoS attacks. As a result of the investments, many major governments and corporations installed dedicated DDoS defense systems. However, even organizations equipped with the product based defense system often showed incompetency in dealing with DDoS attacks with little variations from known attack types. In contrast, by following a capacity centric DDoS detection method, defense personnel can identify various types of DDoS attacks and abnormality of the system through checking availability of service resources, regardless of the types of specific attack techniques. Thus, the defense personnel can easily derive proper response methods according to the attacks. Deviating from the existing DDoS defense framework, this research study introduces a capacity centric DDoS detection methodology and provides methods to mitigate DDoS attacks by applying the methodology.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.25-28
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• 2004

DDoS(Distributed Denial-of-Service) 공격은 인터넷을 통한 보안 위협 중 대표적인 분산 서비스 거부 공격이다. DDoS은 해킹 공격자가 공격 근원지 IP 주소를 스누핑하여 공격목표로 하는 시스템의 가용자원을 고갈시키거나 과도한 부하를 유발시커 서비스를 중단시킨다. 이러한 공격에 대한 대응 기술로 제시된 IP 역추적 기술은 DDoS 공격의 근원지를 판별하고 전달된 공격 패킷을 통하여 네트워크상에서 공격 패킷 전달 경로를 재구성한다. 기존의 역추적 기술인 패킷 마킹 기법에서 DDoS 공격에 대한 판별 과정 없이 임의의 패킷에 대해 역추적 정보를 생성 즉 DDoS 공격에 능동적으로 대응하고 있지 못하는 단점에 착안하여 본 연구에서는 SVM 모듈을 적용한 라우터에서 DDoS 트래픽에 대한 판별 기능을 제공하고 또한 DDoS 공격 패킷에 대해 개선된 마킹 기법을 제시하였다. 연구 실험 결과 네트워크 부하를 줄이면서도 역추적 성능을 향상시킬 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.782-785
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• 2011

최근의 분산 서비스 거부(DDoS) 공격 방법은 점점 더 자동화, 다양화되고 있으며, 단순한 개별 기업에 대한 공격에서부터 국가간의 사이버전쟁으로까지 그 영역이 확대되고 있다. DDoS 공격은 이미 2000 년도 이전부터 발생해온 오래된 공격이고, 이를 방어하기 위한 다양한 DDoS 공격 방어 시스템을 구축하고 있음에도 불구하고 아직까지 이를 효과적으로 차단하지 못하고 있다. 이는 그간 DDoS 공격 방어 시스템이 공격이 시작되었을 때 개개의 공격 패턴을 탐지하고 차단하는 방법으로 발전해 왔기 때문이다. 따라서 좀 더 효과적인 DDoS 공격 대응을 위해 공격 트래픽이 발송되기 전에 클라이언트에서부터 공격에 대응하는 방안이 필요하다. 이에 본 논문에서는 사용자 인증을 통하여 등록된 사용자임을 검증하고, 클라이언트와 인증장비간의 인증을 통해 인증된 사용자의 트래픽만 허용하는 매커니즘을 제안한다.

• The Journal of the Korea Contents Association
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• v.4 no.1
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• pp.49-55
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• 2004

DDoS is an attack type that interfere with normal service by running out network bandwidth, process throughput, and system resource. It can be recognized intuitively by network slowdown and connection impossibility state, but it is necessary to detect DDoS attack by exact and quantitative analysis. In this paper, the exact and efficient DDoS attack detection system which is able to detect traffic flooding by MIB information, and attack traffic by packet analysis is proposed and realized.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.667-669
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• 2012

Traditional DDoS defence methods are performed at server side which was attacked. If servers detect DDoS attack, they use some methods for defending the attack such as increasing the bandwidth, bypassing the traffic, blocking the IP addresses or blocking the ports by the firewall. But as lots of people use smart-phones, it is possible a smart-phone to be a zombie and DDoS attack could be much more a huge and powerful forms than now. Victims are not only a server but also a host which becomes a zombie. While it performs DDoS attack, zombie smart-phone users have to pay the extra charge. After finish the attack, DDoS try to destroy hard drives of zombie hosts. Therefore the situation is changed rather than to defend DDoS server side only, we should protect a client side who needs to prevent DDoS attacks. In this paper, we study a defence method that we terminates a process which perform the attack, send the information to different hosts when a zombie PC or smart-phone perform DDoS attacks.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.3
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• pp.679-689
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• 2012

There were clear differences between the DDoS attack on 7th July 2009 and the rest of them prior to the attack. Despite It had emitted relatively small sized packets per infected PC, the attack was very successful making use of HTTP Flooding attack by aggregating small sized packets from the well sized zombie network. As the objective of the attack is not causing permanent damage to the target system but temporal service disruption, one should ensure the availability of the target server by deploying effective defense strategy. In this paper, a novel HTTP based DDoS defense mechanism is introduced with capacity based defense-in-depth strategy.