• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.13 no.2
• /
• pp.115-125
• /
• 2003

As Web services are generally open for external uses and not filtered by Firewall, these result in attacker's target. Web attacks which exploit vulnerable web-applications and malicious users' requests cause economical and social problems. In this paper, we are modelling general web service usages based on user-web-session and detect anomal usages with Bayesian estimation method. Finally we propose SAD(Session Anomaly Detection) for detection unknown web attacks. To evaluate SAD, we made an experiment on attack simulation with web vulnerability scanner, whisker. The results show that the detection rate of SAD is over 90%, which is influenced by several features such as size of window or training set, detection filter method and web topology.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.7 no.5
• /
• pp.1041-1051
• /
• 2012

Attack on Cloud Computing, an intensive service solution using network infrastructure recently released, generates service breakdown or intrusive incidents incapacitating developmental platforms, web-based software, or resource services. Therefore, it is needed to conduct research on security for the operational information of three kinds of services (3S': laaS, PaaS, SaaS) supported by the Cloud Computing system and also generated data from the illegal attack on service blocking. This paper aims to build a system providing optimal services as a 4-stage defensive method through the test on the attack and defense of Cloud Computing services. It is a defense policy that conducts 4-stage, orderly and phased access control as follows: controlling the initial access to the network, controlling virtualization services, classifying services for support, and selecting multiple routes. By dispersing the attacks and also monitoring and analyzing to control the access by stage, this study performs defense policy realization and analysis and tests defenses by the types of attack. The research findings will be provided as practical foundational data to realize Cloud Computing service-based defense policy.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2009.04a
• /
• pp.1466-1469
• /
• 2009

최근 웹 서비스 환경에서 공격자가 자신의 근원지를 은닉하기 위하여 여러 단계의 경유지를 거쳐 공격을 시도하는 사례가 증가하고 있으며, 이에 대한 법률적 증거 확보 및 능동적인 대처를 위하여 웹 어플리케이션에서의 역추적 기술이 필요하다. 현재 자바 애플릿이나 ActiveX, 플러그인, 웹 로그 등을 이용한 응용 계층의 추적 기술이 개발되고 있지만, 웹 클라이언트에 의하여 차단될 가능성이 높고, 플러그인 종류 및 호환되지 않는 운영 환경 등 제약조건으로 인하여 사용에 제한이 있다. 본 논문에서는 액션 스크립트를 이용한 웹 클라이언트 모니터링 시스템을 제안한다. 제안된 시스템은 웹 클라이언트가 실행을 인식하지 못하고 수행되어 웹 클라이언트에 의한 차단을 막을 수 있고, 다양한 운영 환경에서 사용이 가능하다.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.31 no.4
• /
• pp.779-791
• /
• 2021

Common web services have been continuously targeted by hackers due to an access control policy that must be allowed to an unspecified number of people. In order to cope with this situation, companies regularly check web vulnerabilities and take measures according to the risk of discovered vulnerabilities. The risk of these web vulnerabilities is calculated through preliminary statistics and self-evaluation of domestic and foreign related organizations. However, unlike static diagnosis such as security setting and source code, web vulnerability check is performed through dynamic diagnosis. Even with the same vulnerability item, various attack results can be derived, and the degree of risk may vary depending on the subject of diagnosis and the environment. In this respect, the predefined risk level may be different from that of the actual vulnerability. In this paper, to improve this point, we present a web vulnerability risk assessment model based on the attack result centering on the cyber kill chain.

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

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.18 no.4
• /
• pp.111-122
• /
• 2008

Web service is defined to support interoperable machine to machine interaction over a network and defined as distributed technologies. Recently in web service environment, security has become one of the most critical issues. An attacker may expose user privacy and service information without authentication. Furthermore, the users of web services must temporarily delegate some or all of their behalf. This results in the exposure of user privacy information by agents. We propose a delegation model for providing safety of web service and user privacy in ubiquitous computing environments. In order to provide safety of web service and user privacy, XML-based encryption and a digital signature mechanism need to be efficiently integrated. In this paper, we propose web service management server based on XACML, in order to manage services and policies of web service providers. For this purpose, we extend SAML to declare delegation assertions transferred to web service providers by delegation among agents.

• Journal of Digital Convergence
• /
• v.11 no.3
• /
• pp.273-277
• /
• 2013

Phishing attacks have been implemented in smarter, more advanced ways with the passage of time. Hackers use intelligent phishing attacks to take over computers and to penetrate internal networks in major organizations. So, in this paper, a model for a prevention of phishing attack spread is conceptual designed in order to protect internal users and sensitive or important information from sophisticated phishing attacks. Internal users simultaneously utilize both external web and organizational mail services. And hackers can take the both side equally as a vector. Thus, packets in each service must be monitored and stored to recognize threatening elements from both sides. The model designed in this paper extends the mail server based security structure used in conventional studies for the protection of Internet mail services accessed by intranet users. This model can build a list of phishing sites as the system checks e-mails compared to that of the method that directly intercepts accesses to phishing sites using a proxy server, so it represents no standby time for request and response processes.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2020.05a
• /
• pp.626-629
• /
• 2020

인터넷의 발전으로 웹 서비스를 사용하는 사용자가 기하급수적으로 늘어났고 사용자에게 다양한 서비스를 제공하기 위해 많은 기술이 등장하고 있다. 서비스를 받는 사용자의 웹브라우저에서도 서버의 많은 기술을 구현할 수 있는 공간을 제공하고 있는데 바로 Web Storage와 Indexed DB이다. Web Storage는 용도에 따라 수 MB 정도를 사용하지만 많은 양의 데이터를 구조화하여 사용한다면 Indexed DB가 적합하다. 하지만 Web Storage뿐만 아니라 Indexed DB 역시 영속적이고 평문의 데이터를 저장하고 있다. 이러한 데이터는 웹 보안에 취약하여 XSS 등의 공격에 사용자의 데이터가 노출되어 탈취되거나 편집되어 악용될 우려가 매우 크다. 본 논문에서는 이와 같은 취약점을 보완하기 위해 운영체제와 디바이스 정보를 이용하여 사용자를 인증하고 암호화하는 기법을 구현하여 성능평가를 하였다.

• Convergence Security Journal
• /
• v.18 no.5_1
• /
• pp.113-120
• /
• 2018

Today, the development of information and communication technology is rapidly increasing the number of users of network-based service, and enables real-time information sharing among users on the Internet. There are various methods in the information sharing process, and information sharing based on portal service is generally used. However, the process of information sharing serves as a cause of illegal activities in order to amplify the social interest of the relevant stakeholders. Public opinion attack using macro function can distort normal public opinion, so security measures are urgent. Therefore, security measures are urgently needed. Macro attacks are generally defined as attacks in which illegal users acquire multiple IP or ID to manipulate public opinion on the content of a particular web page. In this paper, we analyze network path information based on traceback for macro attack of a specific user, and then detect multiple access of the user. This is a macro attack when the access path information for a specific web page and the user information are matched more than once. In addition, when multiple ID is accessed for a specific web page in the same region, it is not possible to distort the overall public opinion on a specific web page by analyzing the threshold count value.

• Review of KIISC
• /
• v.25 no.6
• /
• pp.28-46
• /
• 2015

과거 인터넷 뱅킹 서비스에서 클라이언트와 서버 채널 사이에 암호기술을 활용하여 안전한 채널을 구성함으로서 인증, 무결성, 부인방지, 암호화 등의 보안요건을 만족하였지만, 현재의 인터넷 뱅킹 서비스에서 제3자인 공격자는 수학적으로 안전성이 보장된 네트워크상의 보안채널을 공격하는 것이 아니라, 채널의 끝부분인 사용자의 전자적 장치나 금융기관의 웹 서버, 데이터베이스 서버, 어플리케이션 서버 등을 포함하는 인터넷 뱅킹 서버나 내부자에 의하여 내부 호스트에 대한 공격을 시도하는 추세이다. 따라서 이러한 위협에 대응하기 위하여 최근 금융기관에서는 접근 매체를 활용하여 거래를 요청하는 주체가 사용자 본인임을 확인하기 위한 다양한 수단을 도입하고 있으며, 이에 대하여 조사한 결과를 서술한다.