• Journal of the Korea Society of Computer and Information
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• v.10 no.2 s.34
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• pp.105-112
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• 2005

As the development of information telecommunication technology and thus the information sharing and opening is accelerated, If system is exposed to various threatener and the avrious security incident is rasing its head with social problem. As countermeasure, to protect safely and prepare in the attack for a system from a be latent security threat, various security systems are been using such as IDS, Firewall, VPN etc.. But, expertise or expert is required to handle security system. The module, implemented in this paper, is based on Windows XP, like Linux and Unix, and has effect integrity and non-repudiation for a file.

• Journal of KIISE
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• v.44 no.4
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• pp.352-362
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• 2017

This paper analyzes security threats in Security Enhanced (SE) Android and proposes a new technique to efficiently protect application data including private information on rooted Android phones. On an unrooted device, application data can be accessed by the application itself according to the access control models. However, on a rooted device, a root-privileged shell can disable part or all of the access control model enforcement procedures. Therefore, a root-privileged shell can directly access sensitive data of other applications, and a malicious application can leak the data of other applications outside the device. To address this problem, the proposed technique allows only some specific processes to access to the data of other applications including private information by modifying the existing SEAndroid Linux Security Module (LSM) Hook function. Also, a new domain type of process is added to the target system to enforce stronger security rules. In addition, the proposed technique separates the directory type of a newly installed application and the directory type of previously installed applications. Experimental results show that the proposed technique can effectively protect the data of each application and incur performance overhead up to or less than 2 seconds.

• The Journal of the Korea Contents Association
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• v.5 no.5
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• pp.182-190
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• 2005

As computers and Internet become popular, many corporations and countries are using information protection system and security network to protect their informations and resources in internet. But the Intrusional possibilities are increases in open network environments such as the Internet. Even though many security systems were developed, the implementation of these systems are mostly application level not kernel level. Also many file protection systems were developed, but they aren't used widely because of their inconvenience in usage. In this paper, we implement a kernel module to support a file protection function using Loadable Kernel Module (LKM) on Linux. When a system is damaged due to intrusion, the file system are easily recovered through periodical file system image backup.

• Review of KIISC
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• v.13 no.4
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• pp.37-48
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• 2003

응용 수준에서 정보보호를 위한 침입차단시스템(Firewall)과 침입탐지시스템(IDS)은 조직 내의 컴퓨터 서버 보안 대책으로는 그 한계를 갖고 있다. 이에 따라 보안 운영체제(Secure OS)에 관한 필요성이 점차 사회적으로 공감대를 형성하고 있다. 본 고에서는 보안 리눅스 운영체제의 필요성, 기존 리눅스의 보안성, 보안 리눅스의 개발에 따른 요구사항과 개발 방법을 기술한다. 또한 최근 보안 리눅스 연구 동향으로 미국, 일본, 독일 등의 리눅스 보안 연구동향을 살펴보고, 국내 연구기관과 업체의 제품 출시 현황을 살펴본다. 특히 최근 리눅스 커널 2.5.29부터 표준기능으로 포함되고 있는 커널 보안 모듈 방식인 LSM(Linux Security Module)의 기본 구조를 살펴본다. 현재 국내에서 개발하여 보급되고 있는 보안 리눅스 운영체제는 기존 리눅스 커널에 시스템 호출 후킹을 통한 LKM 방식으로 추가적인 접근제어 외에 해킹 차단, 감사 추적, root의 권한 제한, 통합보안관리 등의 추가적 기능을 제공한다. 향후 Firewall, IDS의 한계를 보완하는 서버 보안 대책으로 활발한 보급이 예상된다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.330-333
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• 2002

일반적으로 시스템들은 관리자를 위한 많은 로깅 기능을 제공한다. 이러한 로깅 기능에는 사용자 행위를 파악하는 부분도 제공하고 있으나 정작 사용자들이 입력하는 명령어를 직접 로깅하는 기능은 없거나 매우 미약하다. 시스템 사용자들이 입력한 명령어는 시스템 자체에서 사용자가 어떤 행위를 하였는가를 가장 확실히 보여주는 중요한 단서이다. 본 논문에서는 리눅스 커널을 기반으로 하여 사용자 키스트로크를 로그로 남길 수 있는 방법을 제안하고 구현한다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.317-321
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• 2002

최근 Firewall, IDS와 같은 응용프로그램 수준의 보안 제품은 내부서버 자체의 취약성을 방어하지 못한다. 본 논문에서는 TCSEC C2급에 해당하는 보안성을 가지는 리눅스를 LKM(Loadable Kernel Module) 방법으로 B1급 수준의 다중등급 보안을 구현하였다, 따라서 구현된 다중등급 보안 리눅스 커널의 주요 기능을 기술하고, 시험 평가로서 강제적 접근제어, 성능 및 해킹 시험을 실시하였다. 구현된 보안 커널 기반의 리눅스 운영체제는 B1급의 요구사항을 만족하며, root의 권한 제한, DB를 이용한 실시간 감사추적, 해킹차단, 통합보안관리등의 추가적 기능을 제공한다.

• Convergence Security Journal
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• v.7 no.4
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• pp.123-131
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• 2007

Recently, various threat and security incident are occurred for unspecified individuals, and this problem increases as the rapid of information sharing through Internet. The using of Information Security System such as IDS, Firewall, VPN etc. makes this problem minimal. However, professional knowledge or skill is needed in that case, normal user can't operate the Information Security System. This paper designs and implements File Access Control Module(FACM) to use easily for normal user against malicious threats and attacks. The FACM can exclude from malicious threats and attacks based on operation system rather than detection of threats and attacks. The FACM is working not only Windows System but also Linux System, and the FACM has effect on access control, integrity and non-repudiation for a file with an access control over files on the each OS that are used by multi-user.

• Journal of the Korea Society of Computer and Information
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• v.9 no.1
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• pp.79-86
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• 2004

In general, operating system is offering the security function of OS level to support several web services. However, it is true that security side of OS level is weak from many parts. Specially, it is needed to audit/trace function in security kernel level to satisfy security more than B2 level that define in TCSEC(Trusted Computer System Evaluation Criteria). So we need to create audit data at system call invocation for this, and do to create audit data of equal format about almost event and supply information to do traceback late. This Paper Proposes audit/trace system module that use LKM(Loadable Kernel Module) technique. It is applicable without alteration about existing linux kernel to ensure safe evidence. It offers interface that can utilize external audit data such as intrusion detection system, and also offers safe role based system that is divided system administrator and security administrator These data will going to utilize to computer forensics' data that legal confrontation is Possible.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.821-830
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• 2006

As internet worms are spread out worldwide, the detection and filtering of worms becomes one of hot issues in the internet security. As one of implementation methods to detect worms, the Linux Netfilter kernel module can be used. Its basic operation for worm detection is a string matching where coming packet(s) on the network is/are compared with predefined worm signatures(patterns). A worm can appear in a packet or in two (or more) succeeding packets where some part of worm is in the first packet and its remaining part is in its succeeding packet(s). Assuming that the maximum length of a worm pattern is less than 1024 bytes, we need to perform a string matching up to two succeeding packets of 2048 bytes. To do so, Linux Netfilter keeps the previous packet in buffer and performs matching with a combined 2048 byte string of the buffered packet and current packet. As the number of concurrent connections to be handled in the worm detection system increases, the total size of buffer (memory) increases and string matching speed becomes low In this paper, to reduce the memory buffer size and get higher speed of string matching, we propose a string matching scheme without using buffer. The proposed scheme keeps the partial matching result of the previous packet with signatures and has no buffering for previous packet. The partial matching information is used to detect a worm in the two succeeding packets. We implemented the proposed scheme by modifying the Linux Netfilter. Then we compared the modified Linux Netfilter module with the original Linux Netfilter module. Experimental results show that the proposed scheme has 25% lower memory usage and 54% higher speed compared to the original scheme.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.11
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• pp.427-432
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• 2014

The Purpose of local system attacks is to acquire administrator's(root) privilege shell through the execution of the malicious program or change the flow of the program. This acquiring shell through attack is still valid approach method and it is difficult to cope with improving each of vulnerability because the attacker can select various forms of attack. Linux allocate a set of credentials when login, in order to manage user permissions. Credentials were issued and managed by the kernel directly, and also the kernel ensures that any change cannot be occurred outside of kernel. But, user's credentials that acquired root privilege through system attacks occurs a phenomenon that does not remain consistent. In this paper we propose a security module to detect a security threats that may cause to users and tasks by analysis user task execution and inconsistency credentials.