• Review of KIISC
• /
• v.30 no.3
• /
• pp.47-57
• /
• 2020

2019년에는 기존 랜섬웨어의 변형된 형태 또는 새롭게 개발된 형태의 랜섬웨어 공격이 전 세계적으로 발생했다. 공격에 따른 금전적 피해의 증가를 방지하기 위해 랜섬웨어의 파일 암호화 과정의 암호기능을 분석하여 복구 가능성을 판단할 필요가 있다. 본 논문에서는 2019년 한 해 발생한 다양한 랜섬웨어의 실행과정, 암호화 과정, 키 생성 과정 등을 분석하여 복구 가능성을 판단하고자 한다.

• Journal of Convergence Society for SMB
• /
• v.6 no.2
• /
• pp.31-36
• /
• 2016

Sniffing attack is a passive attack which is reassembling packets to collect personal information, bank accounting number, and other important information. Sniffing attack happens in LAN and uses promiscuous mode which is opening filtering by pass all packets in LAN, attackers could catch any packets in LAN, so they can manipulate packets. They are Switch Jamming, Port mirroring, ARP Redirect, and ICMP Redirect attack. To defend these attacks, I proposed to use SSL packet encryption, reconfiguration of switching environment, DNS, and decoy method for defending all kinds of Sniffing attacks.

• The Journal of the Korea Contents Association
• /
• v.11 no.4
• /
• pp.33-41
• /
• 2011

Although conventional text-based passwords are used as the most common authentication method, they have significant drawbacks such as guess attacks, dictionary attacks, key loggers, and shoulder-surfing. To address the vulnerabilities of traditional text-based passwords, graphical password schemes have been developed as possible alternative solutions, but they have a potential drawback that they are more vulnerable to shoulder-surfing than conventional text-based passwords. In this paper, we present a new Hangul password input method to prevent shoulder-surfing attacks. Our approach uses Hangul as a password, and it requires the users to locate their password in the given wheeling password grid instead of entering the password. Our approach makes it difficult for attackers to observe a user's password since the system shows the users' passwords with decoy characters as the noise on the screen. Also, we provide security analysis for random attacks, dictionary attacks, and shoulder-surfing attacks, and it shows that our password system is robust against these attacks.

• Convergence Security Journal
• /
• v.11 no.6
• /
• pp.9-15
• /
• 2011

It is difficult to identify attack requests from normal ones when those attacks are based on CSRF which enables an attacker transmit fabricated requests of a trusted user to the website. For the protection against the CSRF, there have been a lot of research efforts including secret token, custom header, proxy, policy model, CAPTCHA, and user reauthentication. There remains, however, incapacitating means and CAPTCHA and user reauthentication incur user inconvenience. In this paper, we propose a method to detect CSRF attacks by analyzing the structure of websites and the usage patterns. Potential victim candidates are selected and website usage patterns according to the structure and usage logs are analyzed. CSRF attacks can be detected by identifying normal usage patterns. Also, the proposed method does not damage users' convenience not like CAPTCHA by requiring user intervention only in case of detecting abnormal requests.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.3
• /
• pp.91-97
• /
• 2010

Recently Hu-Niu-Yang proposed the user authentication scheme to improve Liu et al's scheme. But the Hu-Niu-Yang's scheme has not been satisfied security requirements considering in the user authentication scheme using the password based smart card. In this paper, we proved that Hu-Niu-Yang's scheme is vulnerable to the off-line password guessing attack in case that the attacker steals the user's smart card and extracts the information in the smart card. Also, the improved user authentication scheme solving the security vulnerability was introduced, thus preventing the attacks, such as password guessing attack, forgery attack impersonation attack, and replay attack. For preventing those attacks, the our proposed scheme need more hash functions and exclusive-OR operations than Hu-Niu-Yang's scheme.

• The KIPS Transactions:PartB
• /
• v.12B no.4 s.100
• /
• pp.443-450
• /
• 2005

Digital fingerprinting is a contents-protection technique, where customer information is inserted into digital contents. Fingerprinted contents undergo various attacks. Especially, attackers can remove easily the inserted fingerprint by collusion attacks, because digital fingerprinting inserts slightly different codes according to the customers. Among collusion attacks, averaging attack is a simple, fast, and efficient attack. In this paper, we propose a video fingerprinting system that is robust to the averaging attack. In order to achieve code efficiency and robustness against the averaging attack, we adopt anti-collusion code (fingerprint code) from GD-PBIBD theory. When the number of users is increased, the size of fingerprint code also grows. Thus, this paper addresses a zero-based code modulation technique to embed and detect this fingerprint code efficiently. We implemented a blind video fingerprinting system based on our proposed technique and performed experiments on various colluding cases. Based on the results, we could detect most of colluders. In the worst case, our scheme could trace at least one colluder successfully.

• Convergence Security Journal
• /
• v.23 no.4
• /
• pp.33-41
• /
• 2023

In recent years, advanced persistent threat (APT) attack organizations have exploited various vulnerabilities and attack techniques to target companies and institutions with national core technologies, distributing ransomware and demanding payment, stealing nationally important industrial secrets and distributing them on the black market (dark web), selling them to third countries, or using them to close the technology gap, requiring national-level security preparations. In this paper, we analyze the attack methods of attack organizations such as Kimsuky and Lazarus that caused industrial secrets leakage damage through APT attacks in Korea using the MITRE ATT&CK framework, and derive 26 cybersecurity-related administrative, physical, and technical security requirements that a company's security system should be equipped with. We also proposed a security framework and system configuration plan to utilize the security requirements in actual field. The security requirements presented in this paper provide practical methods and frameworks for security system developers and operators to utilize in security work to prevent leakage of corporate industrial secrets. In the future, it is necessary to analyze the advanced and intelligent attacks of various APT attack groups based on this paper and further research on related security measures.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.10a
• /
• pp.759-761
• /
• 2016

ICMP(Internet Control Message Protocol) supports the processing of error in the communication network based TCP/IP. If a problem is occurred in a data transmission process, router or receiving host sends ICMP message containing the error cause to sending host. However, in this process an attacker sends a fake ICMP message to the host so that the communication between the hosts can be abnormally terminated. In this paper, we performed a study to prevent several attacks related to ICMP. To this, we have designed outbound traffic controller so that attack packet is not transmitted to network in operating system of host.

• Review of KIISC
• /
• v.13 no.1
• /
• pp.56-63
• /
• 2003

침입감내기술은 기존의 침입차단이나 탐지기술에 의하여 해결될 수 없었던 알려지지 않은 취약점을 이용하는 공격에 의하여 발생하는 시스템의 피해를 방지하기 위한 기술이며, 중요 서비스의 품질요구사항과 지속성 요구사항 만족을 위하여 의존성 특성의 만족이 필요하다. 이러한 침입감내시스템은 결함허용기술과 정보보호기술이 결합된 형태로 접근이 시도되고 있다. 침입감내기술에서는 일반적으로 결함허용기법들이 고려하고 있는 우발적 사고가 아닌 악의적 공격에서 일어날 수 있는 상황들에 대한 고려가 매우 중요하다. 그러므로 침입감내기술에서는 결함허용기술에서 고려하는 것 외에 보안취약성과 공격 개념의 도입, 침입의 탐지와 대처 등 보안성에 대한 요구사항 만족이 필요하다.

• Review of KIISC
• /
• v.28 no.1
• /
• pp.16-21
• /
• 2018

개인식별번호(personal identification number: PIN)는 숫자로 이루어진 짧은 패스워드로서, 은행 ATM, 디지털 도어락, 스마트 디바이스 등에서 사용자 인증을 위해 널리 쓰이고 있다. PIN을 입력하기 위한 전통적인 키패드 방식의 인터페이스는 엿보기나 녹화 등의 공격에 취약하며, 이를 방지하기 위해 다양한 PIN 입력 방식들이 제안된 바 있다. 그러나, 잘못 설계된 PIN 입력 방식은 무작위 대입 공격 등 다른 공격에 대한 안전성이나 사용자 편의성을 떨어뜨릴 수 있다. 이 논문에서는 특히 스마트 디바이스 상에서 PIN을 안전하게 입력하기 위한 다양한 방식들을 조사하고 이들의 특성을 분석함으로써 안전하고 편리한 PIN 입력 방식의 설계를 위한 방향을 제시한다.