• Journal of the Korea Institute of Information Security & Cryptology
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• 제20권5호
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• pp.99-110
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• 2010

Recently, network based DDoS attacks have been changed into application layer DDoS attacks which are targeted at the web services. Specially, an attacker makes zombie PCs generate small traffic and its traffic pattern has been similar to the normal user's pattern. So, existing HTTP PPS based Threshold cannot defend the DDoS attacks effectively. In this paper, we displayed all the GET Flooding attack types and propose three DDoS attack defense mechanisms which are simple and very powerful. Proposed mechanisms can defend all the existing GET Flooding DDoS attacks and be deployed in the real environment immediately with little resource consumption.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권12호
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• pp.6139-6160
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• 2018

For ease of use and access, web browsers are now being used to access and modify sensitive data and systems including critical control systems. Due to their computational capabilities and network connectivity, browsers are vulnerable to several types of attacks, even when fully updated. Browsers are also the main target of phishing attacks. Many browser attacks, including phishing, could be prevented or mitigated by using site-, user-, and device-specific security configurations. However, we discovered that all major browsers expose disparate security configuration procedures, option names, values, and semantics. This results in an extremely hard to secure web browsing ecosystem. We analyzed more than a 1000 browser security configuration options in three major browsers and found that only 13 configuration options had syntactic and semantic similarity, while 4 configuration options had semantic similarity, but not syntactic similarity. We: a) describe the results of our in-depth analysis of browser security configuration options; b) demonstrate the complexity of policy-based configuration of web browsers; c) describe a knowledge-based solution that would enable organizations to implement highly-granular and policy-level secure configurations for their information and operational technology browsing infrastructures at the enterprise scale; and d) argue for necessity of developing a common language and semantics for web browser configurations.

• Journal of Information Processing Systems
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• 제12권3호
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• pp.422-435
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• 2016

Despite the convenience brought by the advances in web and Internet technology, users are increasingly being exposed to the danger of various types of cyber attacks. In particular, recent studies have shown that today's cyber attacks usually occur on the web via malware distribution and the stealing of personal information. A drive-by download is a kind of web-based attack for malware distribution. Researchers have proposed various methods for detecting a drive-by download attack effectively. However, existing methods have limitations against recent evasion techniques, including JavaScript obfuscation, hiding, and dynamic code evaluation. In this paper, we propose an emulation-based malicious webpage detection method. Based on our study on the limitations of the existing methods and the state-of-the-art evasion techniques, we will introduce four features that can detect malware distribution networks and we applied them to the proposed method. Our performance evaluation using a URL scan engine provided by VirusTotal shows that the proposed method detects malicious webpages more precisely than existing solutions.

• Journal of Internet Computing and Services
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• 제23권4호
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• pp.87-94
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• 2022

Recently, with the development of information and communication infrastructure, the number of Internet access devices is rapidly increasing. Smartphones, laptops, computers, and even IoT devices are receiving information and communication services through Internet access. Since most of the device operating environment consists of web (WEB), it is vulnerable to web cyber attacks using web shells. When the web shell is uploaded to the web server, it is confirmed that the attack frequency is high because the control of the web server can be easily performed. As the damage caused by the web shell occurs a lot, each company is responding to attacks with various security devices such as intrusion prevention systems, firewalls, and web firewalls. In this case, it is difficult to detect, and in order to prevent and cope with web shell attacks due to these characteristics, it is difficult to respond only with the existing system and security software. Therefore, it is an automated defense system through the collection and analysis of web shells based on artificial intelligence machine learning that can cope with new cyber attacks such as detecting unknown web shells in advance by using artificial intelligence machine learning and deep learning techniques in existing security software. We would like to propose about. The machine learning-based web shell defense system model proposed in this paper quickly collects, analyzes, and detects malicious web shells, one of the cyberattacks on the web environment. I think it will be very helpful in designing and building a security system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권7호
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• pp.2512-2531
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• 2014

We propose a new Distributed Denial of Service (DDoS) defense mechanism that protects http web servers from application-level DDoS attacks based on the two methodologies: whitelist-based admission control and busy period-based attack flow detection. The attack flow detection mechanism detects attach flows based on the symptom or stress at the server, since it is getting more difficult to identify bad flows only based on the incoming traffic patterns. The stress is measured by the time interval during which a given client makes the server busy, referred to as a client-induced server busy period (CSBP). We also need to protect the servers from a sudden surge of attack flows even before the malicious flows are identified by the attack flow detection mechanism. Thus, we use whitelist-based admission control mechanism additionally to control the load on the servers. We evaluate the performance of the proposed scheme via simulation and experiment. The simulation results show that our defense system can mitigate DDoS attacks effectively even under a large number of attack flows, on the order of thousands, and the experiment results show that our defense system deployed on a linux machine is sufficiently lightweight to handle packets arriving at a rate close to the link rate.

• Journal of the Korea Institute of Information Security & Cryptology
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• 제30권4호
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• pp.669-677
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• 2020

As the number of Internet users exploded, attacks on the web increased. In addition, the attack patterns have been diversified to bypass existing defense techniques. Traditional web firewalls are difficult to detect attacks of unknown patterns.Therefore, the method of detecting abnormal behavior by artificial intelligence has been studied as an alternative. Specifically, attempts have been made to apply natural language processing techniques because the type of script or query being exploited consists of text. However, because there are many unknown words in scripts and queries, natural language processing requires a different approach. In this paper, we propose a new classification model which uses byte pair encoding (BPE) technology to learn the embedding vector, that is often used for web attack payloads, and uses an attention mechanism-based Bi-GRU neural network to extract a set of tokens that learn their order and importance. For major web attacks such as SQL injection, cross-site scripting, and command injection attacks, the accuracy of the proposed classification method is about 0.9990 and its accuracy outperforms the model suggested in the previous study.

• Convergence Security Journal
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• 제12권3호
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• pp.85-92
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• 2012

Today, the typical web hacking attacks are cross-site scripting(XSS) attacks, injection vulnerabilities, malicious file execution and insecure direct object reference included. Web hacking security systems, access control solutions, access only to the web service and flow inside but do not control the packet. So you have been illegally modified to pass the packet even if the packet is considered as a unnormal packet. The defense system is to fail to appropriate controls. Therefore, in order to ensure a successful web services diagnostic system development is necessary. Web application diagnostic system is real and urgent need and alternative. The diagnostic system development process mu st be carried out step of established diagnostic systems, diagnostic scoping web system vulnerabilities, web application, analysis, security vulnerability assessment and selecting items. And diagnostic system as required by the web system environment using tools, programming languages, interfaces, parameters must be set.

• Journal of the Korea Society of Computer and Information
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• 제17권5호
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• pp.33-40
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• 2012

In this paper we propose an anomaly detection scheme to detect new attack paths or new attack methods without false positives by monitoring HTTP Outbound Traffic after efficient training. Our proposed scheme detects web-based attacks by comparing tags or javascripts of HTTP Outbound Traffic with normal behavioral models which apply HMM(Hidden Markov Model). Through the verification analysis under the real-attacked environment, we show that our scheme has superior detection capability of 0.0001% false positive and 96% detection rate.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.736-739
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• 2008

Phishing is a form of online identity theft that aims to steal sensitive information such as online banking passwords and credit card information from users. This paper presents a novel browser extension, AntiPhish, that aims to protect users against spoofed web site-based phishing attacks. To this end, AntiPhish tracks the sensitive information of a user and generates warnings whenever the user attempts to give away this information to a web site today requires only the server to be hat is considered untrusted.

• Journal of the Korea Society of Computer and Information
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• 제24권5호
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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.