• Journal of the Korea Society of Computer and Information
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• v.14 no.9
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• pp.55-66
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• 2009

In this paper, I will discuss how the Internet has spread rapidly in our lives. Large portals and social networks experience service attacks that access personal customers' databases. This interferes with normal service through DDoS (Distribute Denial of Service Attack), which is the topic I want to discuss. Among the types of DDoS, TCP SYN Flooding attacks are rarely found because they use few traffics and its attacking type is regular transaction. The purpose of this study is to find and suggest the method for accurate detection of the attacks. Through the analysis of TCP SYN Flooding attacks, we find that these attacks cause Backscatter effect. This study is about the algorithm which detects the attacks of TCP SYN Flooding by the study of Backscatter effect.

• Convergence Security Journal
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• v.12 no.6
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• pp.101-106
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• 2012

As the existing strategy of preventing DDoS(Distributed Denial of Service) attacks has limitations, this study is intended to suggest the more effective method of preventing DDoS attacks which reduces attack power and distributes attack targets. Currently, DDoS attacks have a wide range of targets such as individuals, businesses, labs, universities, major portal sites and financial institutions. In addition, types of attacks change from exhausting layer 3, network band to primarily targeting layer 7. In response to DDoS attacks, this study suggests how to distribute and decrease DDoS threats effectively and efficiently using Proxy Server Group and Dynamic DNS.

• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.642-645
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• 2010

본 논문에서는 DDoS(Distribute Denial of Service) 공격 상황에서의 효율적인 iptables 정책 설계 방법에 대해 제안한다. 현재 구축된 인터넷 상황에서는 누구나 손쉽게 DDoS Attack 환경을 구축하여 특정 사이트를 공격할 수 있다. 이를 극복하기 위해 DDoS 방어전용 장비 등을 사용 할 수 있지만 고가라는 단점 때문에 개인 혹은 소규모 서비스 시스템에서 사용하기에 어려운 점이 많다. 본 논문은 이러한 상황을 극복하기 위해 개인 및 소규모 시스템에 적용 가능한 효율적인 iptables 정책을 제안한다. 제안한 각 정책별 성능 평가는 웹 서비스 환경과 DDoS 유형별 공격 시나리오를 가정하여 시행하였고, 이는 실제적으로 효과가 있음을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.729-732
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• 2010

통신망의 발달로 다양한 인터넷 기반 기술들이 등장함에 따라 현재는 데이터뿐만 아닌 음성에 대한 부분도 IP 네트워크를 통해 전송하려는 움직임이 발판이 되어 VoIP(Voice Over Internet Protocol)라는 기술이 등장하였다. SIP(Session Initiation Protocol) 프로토콜 기반 VoIP 서비스는 통신 절감 효과가 큰 장점과 동시에 다양한 부가서비스를 제공하여 사용자 수가 급증하고 있다. VoIP 서비스는 호(Call)를 제어하기 위해 SIP 기반으로 구성이 되며, SIP 프로토콜은 IP 망을 이용하여 다양한 음성과 멀티미디어 서비스를 제공하게 되는데 IP 프로토콜에서 발생하는 인터넷 보안 취약점을 그대로 동반하기 때문에 DoS(Denial of Service) 및 DDoS(Distribute Denial of Service)에 취약한 성향을 가지고 있다. DDoS 공격은 단시간 내에 대량의 패킷을 타깃 호스트 또는 네트워크에 전송하여 네트워크 접속 및 서비스 기능을 정상적으로 작동하지 못하게 하거나 시스템의 고장을 유도하게 된다. 인터넷 기반 생활이 일상화 되어 있는 현 시점에서 안전한 네트워크 환경을 만들기 위해 DDoS 공격에 대한 대응 방안이 시급한 시점이다. DDoS 공격에 대한 탐지는 매우 어렵기 때문에 근본적인 대책 마련에 대한 연구가 필요하며, 정상적인 트래픽 및 악의적인 트래픽에 대한 탐지 시스템 개발이 절실히 요구되는 사항이다. 본 논문에서는 SIP 프로토콜 및 공격기법에 대해 조사하고, DoS와 DDoS 공격에 대한 특성 및 종류에 대해 조사하였으며, SIP를 이용한 VoIP 서비스에서 IP 분류와 메시지 중복 검열을 통한 DDoS 공격 탐지기법을 제안한다.

• Journal of the Korea Society of Computer and Information
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• v.11 no.6 s.44
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• pp.185-192
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• 2006

By mistaking normal packets for harmful traffic, it may not offer service according to the intention of attacker with harmful traffic, because it is not easy to classify network traffic for normal service and it for DUoS(Distributed DoS) attack like the Internet worm. And in the IPv6 environment these researches on harmful traffic are weak. In this dissertation, hosts in the IPv6 environment are attacked by NETWIB and their attack traffic is monitored, then the statistical information of the traffic is obtained from MIB(Management Information Base) objects used in the IPv6. By adapting the ESM(Exponential Smoothing Method) to this information, a normal traffic boundary, i.e., a threshold is determined. Input traffic over the threshold is thought of as attack traffic.

• Convergence Security Journal
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• v.9 no.4
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• pp.7-12
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• 2009

It is very difficult to completely block the DDoS attack, which paralyzes services by depleting resources or occupying the network bandwidth by transmitting a vast amount of traffic to the specific website or server from normal users' PCs that have been already infected by an outside attacker. In order to defense or endure the DDoS attack, we usually use various solutions such as IDS (Intrusion Detection System), IPS (Intrusion Prevention System), ITS (Intrusion Tolerance System), FW (Firewall), and the dedicated security equipment against DDoS attack. However, diverse types of security appliances cause the cost problem, besides, the full function of the equipments are not performed well owing to the unproper setting without considering connectivity among systems. In this paper, we present the effective connectivity of security equipments and countermeasure methodology against DDoS attack. In practice, it is approved by experimentation that this designed methdology is better than existing network structure in the efficiency of block and endurance. Therefore, we would like to propose the effective security control measures responding and enduring against discriminated DDoS attacks through this research.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.15-26
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• 2011

The development of IT technology and information communication networks activated to online financial transactions; the users were able to get a variety of financial services. However, unlike the positive effect that occurred on 7 July 2009 DDoS(Distribute Denial of Service) attacks, such as damaging to the user, which was caused negative effects. Authentication technology(OTP) is used to online financial transaction, which should be reviewed to safety with various points because the unpredictable attacks can bypass the authentication procedure such as phishing sites, which is occurred. Thus, this paper proposes mobile OTP(One Time Password) Mechanism, which is based on PKI to improve the safety of OTP authentication. The proposed Mechanism is operated based on PKI; the secret is transmitted safely through signatures and public key encryption of the user and the authentication server. The users do not input in the web site, but the generated OTP is directly transmitted to the authentication server. Therefore, it is improvement of the availability of the user and the resolved problem is exposed from the citibank phishing site(USA) in 2006.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.11
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• pp.743-754
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• 2014

Recently, Information-Centric Networking(ICN), different from traditional IP-based networking, has been highlighted. Content-Centric Networking(CCN), proposed by Van Jacobson, is a representative scheme of the ICN architectures. It can deliver messages slightly faster than the IP-based networking by focusing on the access and delivery to the content itself. However, CCN is restricted to distribute the information without transmitting the request packet in advance because it is pull-based architecture by content requester. In addition, it has a problem that the Pending Interest Table(PIT) could be overloaded easily when DDoS attack happens. In this paper, we suggest an algorithm using a push-based scheme without request packets and overcoming PIT overload situation by Interest Group Push Table(IGPT). The proposed scheme enables to transmit a large amount of content than an existing scheme during the same amount of time in terms of timely-delivery and security.