Abstract. Kernel rootkits pose a significant threat to computer systems as they run at the highest privilege level and have unrestricted access to the resources of their victims. Many current efforts in kernel rootkit defense focus on the detection of kernel rootkits -after a rootkit attack has taken place, while the smaller number of efforts in kernel rootkit prevention exhibit limitations in their capability or deployability. In this paper we present a kernel rootkit prevention system called NICKLE which addresses a common, fundamental characteristic of most kernel rootkits: the need for executing their own kernel code. NICKLE is a lightweight, virtual machine monitor (VMM) based system that transparently prevents unauthorized kernel code execution for unmodified commodity (guest) OSes. NICKLE is based on a new scheme called memory shadowing, wherein the trusted VMM maintains a shadow physical memory for a running VM and performs real-time kernel code authentication so that only authenticated kernel code will be stored in the shadow memory. Further, NICKLE transparently routes guest kernel instruction fetches to the shadow memory at runtime. By doing so, NICKLE guarantees that only the authenticated kernel code will be executed, foiling the kernel rootkit's attempt to strike in the first place. We have implemented NICKLE in three VMM platforms: QEMU+KQEMU, VirtualBox, and VMware Workstation. Our experiments with 23 real-world kernel rootkits targeting the Linux or Windows OSes demonstrate NICKLE's effectiveness. Furthermore, our performance evaluation shows that NICKLE introduces small overhead to the VMM platform.

No abstract

Kernel rootkits, malicious software designed to compromise a running operating system kernel, are difficult to analyze and profile due to their elusive nature, the variety and complexity of their behavior, and the privilege level at which they run. However, a comprehensive kernel rootkit profile that reveals key aspects of the rootkit's behavior is helpful in aiding a detailed manual analysis by a human expert. In this paper we present PoKeR, a kernel rootkit profiler capable of producing multi-aspect rootkit profiles which include the revelation of rootkit hooking behavior, the exposure of targeted kernel objects (both static and dynamic), assessment of userlevel impacts, as well as the extraction of kernel rootkit code. The system is designed to be deployed in scenarios which can tolerate high overheads, such as honeypots. Our evaluation results with a number of real-world kernel rootkits show that PoKeR is able to accurately profile a variety of rootkits ranging from traditional ones with system call hooking to more advanced ones with direct kernel object manipulation. The obtained profiles lead to unique insights into the rootkits' characteristics and demonstrate PoKeR's usefulness as a tool for rootkit investigators.

Abstract-We consider the problem of how to provide an execution environment where the application's secrets are safe even in the presence of malicious system software layers. We propose Iso-X -a flexible, fine-grained hardware-supported framework that provides isolation for security-critical pieces of an application such that they can execute securely even in the presence of untrusted system software. Isolation in Iso-X is achieved by creating and dynamically managing compartments to host critical fragments of code and associated data. Iso-X provides fine-grained isolation at the memory-page level, flexible allocation of memory, and a low-complexity, hardwareonly trusted computing base. Iso-X requires minimal additional hardware, a small number of new ISA instructions to manage compartments, and minimal changes to the operating system which need not be in the trusted computing base. The run-time performance overhead of Iso-X is negligible and even the overhead of creating and destroying compartments is modest. Iso-X offers higher memory flexibility than the recently proposed SGX design from Intel, allowing both fluid partitioning of the available memory space and dynamic growth of compartments. An FPGA implementation of Iso-X runtime mechanisms shows a negligible impact on the processor cycle time.

Abstract. This paper introduces a new software polymorphism technique that randomizes program data structure layout. This technique will generate different data structure layouts for a program and thus diversify the binary code compiled from the same program source code. This technique can mitigate attacks (e.g., kernel rootkit attacks) that require knowledge about data structure definitions. It is also able to disrupt the generation of data structure-based program signatures. We have implemented our data structure layout randomization technique in the open source compiler collection gcc-4.2.4 and applied it to a number of programs. Our evaluation results show that our technique is able to achieve software binary diversity. We also apply the technique to one operating system data structure in order to foil a number of kernel rootkit attacks. Meanwhile, programs produced by the technique were analyzed by a state-of-the-art data structure inference system and it was demonstrated that reliance on data structure signatures alone may lead to false negatives in malware detection.