• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.24 no.1
• /
• pp.87-95
• /
• 2014

Under only authorized AP is allowable environment, rogue AP which is generated by a smartphone tethering can be a serious security breach. To solve rogue AP problem, this paper proposes classifying algorithm of Kernel Support Vector Machine using features of RTT data. Through our experiment, we can detect rogue AP from LTE mobile network.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.23 no.5
• /
• pp.931-938
• /
• 2013

It is hard to extract original data from encrypted data before getting the password in encrypted data with disk encryption software. This encryption key of disk encryption software can be extract by using physical memory analysis. Searching encryption key time in the physical memory increases with the size of memory because it is intended for whole memory. But physical memory data includes a lot of data that is unrelated to encryption keys like system kernel objects and file data. Therefore, it needs the method that extracts valid data for searching keys by analysis. We provide a method that collect only saved memory parts of disk encrypting keys in physical memory by analyzing Windows kernel virtual address space. We demonstrate superiority because the suggested method experimentally reduces more of the encryption key searching space than the existing method.

• Journal of KIISE:Computing Practices and Letters
• /
• v.10 no.2
• /
• pp.146-155
• /
• 2004

Currently most of commercial operating systems contain a high-level audit feature to increase their own security level. Linux does not fall behind the other commercial operating systems in performance and stability, but Linux does not have a good audit feature. Linux is required to support a higher security feature than C2 level of the TCSEC in order to be used as a server operating system, which requires the kernel-level audit feature that provides the system call auditing feature and audit event. In this paper, we present LxBSM, which is a kernel module to provide the kernel-level audit features. The audit record format of LxBSM is compatible with that of Sunshield BSM. The LxBSM is implemented as a loadable kernel module, so it has the enhanced usability. It provides the rich audit records including the user-level audit events such as login/logout. It supports both the pipe and file interface for increasing the connectivity between LxBSM and intrusion detection systems (IDS). The performance of LxBSM is compared and evaluated with that of Linux kernel without the audit features. The response time was increased when the system calls were called to create the audit data, such as fork, execve, open, and close. However any other performance degradation was not observed.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
• /
• 2001.11a
• /
• pp.340-347
• /
• 2001

Security operating system applied to MAC(Mandatory Access Control) or to MLS(Multi Level Security) gives both subject and object both Security Level and value of Category, and it restrict access to object from subject. But it violates Security policy of system and could be a circulated course of illegal information. This is correctly IPC(Interprocess Communication)mechanism and Covert Channel. In this thesis, I tried to design and implementation as OS kernel in order not only to give confidence of information circulation in the Security system, but also to defend from Covert Channel by Storage and IPC mechanism used as a circulated course of illegal information. For removing a illegal information flow by IPC mechanism. I applied IPC mechanism to MLS Security policy, and I made Storage Covert Channel analyze system call Spec. and than distinguish Storage Covert Channel. By appling auditing and delaying, I dealt with making low bandwidth.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.9
• /
• pp.1947-1954
• /
• 2011

There are various attacks such as tampering, bypassing and spoofing which are caused with system-wide vulnerabilities of Windows operating system. The underlying operating system is responsible for protecting application-space mechanisms against such attacks. This paper provides the implementation of mandatory access control known as multi-level security (MLS) rating with TCSEC-B1 level on th kernel of Windows$^{TM}$. By adding especially the protection feature against tampering memory of processes to the security kernel, this implementation meets the responsibility against system-wide vulnerabilities.

• The KIPS Transactions:PartC
• /
• v.10C no.7
• /
• pp.929-936
• /
• 2003

We Propose the Suity Cryptography File System to encrypt or decrypt a plaintext or an encrypted tort by using the dynamic linking mechanism In the Linux kernel. The dynamic linking mechanism gives the flexibility of the kernel without changing the kernel. The Sorority Cryptography File System uses the blowfish algorithm to encrypt or decrypt a data. To overcome the overhead of the key server, I use key generating algorithm which is installed in the same Security Cryptography File System. The Security Cryptography file System is fitted into the Linux system.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.13 no.4
• /
• pp.187-194
• /
• 2018

The operating system for IoT should have a small memory footprint and provide low power state, real-time, multitasking, various network protocols, and security. Although the Zephyr kernel, an operating system for IoT, released by the Linux Foundation in February 2016, has these features but errors generated by the user code can generate fatal problems in the system because the Zephyr kernel adopts a single-space method that both the user code and kernel code execute in the same space. In this research, we propose a space separation method, which separates kernel space and user space, to solve this problem. The space separation that we propose consists of three modifications in Zephyr kernel. The first is the code separation that kernel code and user code execute in each space while using different stacks. The second is the kernel space protection that generates an exception by using the MPU (Memory Protection Unit) when the user code accesses the kernel space. The third is the SVC based system call that executes the system call using the SVC instruction that generates the exception. In this research, we implemented the space separation in Zephyr v1.8.0 and evaluated safety through abnormal execution of the user code. As the result, the kernel was not crashed by the errors generated by the user code and was normally executed.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.34 no.3
• /
• pp.365-378
• /
• 2024

The operating system (OS) of mobiles or embedded devices is based on the Linux kernel. These OSs request random numbers from the Linux kernel for system operation, such as encryption keys and security features. To provide random numbers reliably, the Linux kernel has a dedicated random number generator (Linux Pseudo Random Number Generator, LPRNG). Recently, LPRNG has undergone a major structural changes. However, despite the major changes, no security analysis has been published on the structure of the new LPRNG. Therefore, we analyze these structural changes as a preliminary study to utilize the security analysis of the new LPRNG. Furthermore, the differences between before and after the changes are divided into cryptographic and performance perspectives to identify elements that require security analysis. This result will help us understand the new LPRNG and serve as a base for security analysis.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.2097-2100
• /
• 2003

Many studies have been done on secure operating system using secure kernel that has various access control policies for system security. Secure kernel can protect user or system data from unauthorized and/or illegal accesses by applying various access control policies like DAC(Discretionary Access Control), MAC(Mandatory Access Control), RBAC(Role Based Access Control), and so on. But, even if secure operating system is running under various access control policies, network traffic among these secure operating systems can be captured and exposed easily by network monitoring tools like packet sniffer if there is no protection policy for network traffic among secure operating systems. For this reason, protection for data within network traffic is as important as protection for data within local system. In this paper, we propose a secure operating system trusted channel, SOSTC, as a prototype of a simple secure network protocol that can protect network traffic among secure operating systems and can transfer security information of the subject. It is significant that SOSTC can be used to extend a security range of secure operating system to the network environment.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.25 no.4
• /
• pp.863-872
• /
• 2015

Kernel rootkit is recognized as one of the most severe and widespread threats to corrupt the integrity of an operating system. Without an external monitor as a root of trust, it is not easy to detect kernel rootkits which can intercept and modify communications at the interfaces between operating system components. To provide such a monitor isolated from an operating system that can be compromised, most existing solutions are based on external hardware. Unlike those solutions, we develop a kernel introspection system based on the ARM TrustZone technology without incurring extra hardware cost, which can provide a secure memory space in isolation from the rest of the system. We particularly use a secure timer to implement an autonomous switch between secure and non-secure modes. To ensure integrity of reference, this system measured reference from vmlinux which is a kernel original image. In addition, the flexibility of monitoring block size can be configured for efficient kernel introspection system. The experimental results show that a secure kernel introspection system is provided without incurring any significant performance penalty (maximum 6% decrease in execution time compared with the normal operating system).