A Survey of Current Work in Microprogramming

Jones, Louise H.

doi:10.1109/c-m.1975.219050

Cited by 6 publications

(2 citation statements)

References 44 publications

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“…Although Wilkes first introduced the concept of microcode into computer engineering as early as 1951 [9], researchers have paid most attention to diverse branches of research related to micro-programming and optimization of microcode for a long time [10][11] [12]. No one had realized that microcode may be threatening until Thompson proposed the concept of a malicious compiler which is undetectable even by source code analysis in 1984 [13].…”

Section: Related Workmentioning

confidence: 99%

Reverse Engineering of Intel Microcode Update Structure

Yang¹,

Li²,

Zhang³

et al. 2020

IEEE Access

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Microcode update mechanism have been widely used in modern processors. Due to the implementation details are not public, researchers are prevented from gaining any sort of further understanding currently. The microcode update binary which uploaded into Central Processing Unit (CPU) is the only accessible node in this update chain by researchers, but previous manual reverse analysis for a small amount of microcode updates has the disadvantages of incomplete coverage, slow speed, and low accuracy. Therefore, we first build a Sample Repository containing 504 Intel official microcode updates, then propose a semiautomatic analytical method named SJNW-MA to analyze samples. This work has the following merits: (1) automatic methods of similarity analysis and candidate feature mining improve the speed; (2) manual-assisted analysis based on expert knowledge can filter important features, to avoid redundant features or valuable common data blocks missing; (3) analysis for 504 microcode updates make the results of reverse engineering are more complete. Finally, we extract eleven structures of Intel microcode updates and group them into four categories. In addition, we also identify and describe some new metadata in microcode updates of the third and the fourth category, including a new 3072-bit RSA Modulus as well as corresponding RSA Exponent which indicates upgrade of security technology inside update mechanism. INDEX TERMS microcode update, reverse engineering, Central Processing Unit ZH. Yang et al.: Reverse Engineering of Intel Microcode Update Structure ZHIGUO YANG is currently pursuing the master's degree with the State Key Laboratory of Mathematical Engineering and Advanced Computing, China. His research interesting include reverse engineering and vulnerability of hardware, trusted computing. QINGBAO LI is currently a Professor with the State Key Laboratory of Mathematical Engineering and Advanced Computing, China. His researches focus on trusted computing and security of hardware. PING ZHANG is currently a Professor with the State Key Laboratory of Mathematical Engineering and Advanced Computing, China. Her researches focus on binary analysis and disassembly. ZHIFENG CHEN is currently a Lecturer with the State Key Laboratory of Mathematical Engineering and Advanced Computing, China. His research interests include network and information security.

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Section: Related Workmentioning

confidence: 99%

Reverse Engineering of Intel Microcode Update Structure

Yang¹,

Li²,

Zhang³

et al. 2020

IEEE Access

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“…Diverse branches of research related to microprogramming include higher-level microcode languages, microcode compilers and tools, and microcode verification [5,43,56]. Other major research areas focus on optimization of microcode, i.e., minimizing execution time and memory space [32]. In addition, several applications of microprogramming were developed [27] such as diagnostics [41].…”

Section: Related Workmentioning

confidence: 99%

Reverse Engineering x86 Processor Microcode

Koppe¹,

Kollenda²,

Fyrbiak³

et al. 2019

Preprint

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Microcode is an abstraction layer on top of the physical components of a CPU and present in most generalpurpose CPUs today. In addition to facilitate complex and vast instruction sets, it also provides an update mechanism that allows CPUs to be patched in-place without requiring any special hardware. While it is well-known that CPUs are regularly updated with this mechanism, very little is known about its inner workings given that microcode and the update mechanism are proprietary and have not been throughly analyzed yet.In this paper, we reverse engineer the microcode semantics and inner workings of its update mechanism of conventional COTS CPUs on the example of AMD's K8 and K10 microarchitectures. Furthermore, we demonstrate how to develop custom microcode updates. We describe the microcode semantics and additionally present a set of microprograms that demonstrate the possibilities offered by this technology. To this end, our microprograms range from CPU-assisted instrumentation to microcoded Trojans that can even be reached from within a web browser and enable remote code execution and cryptographic implementation attacks.

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Adaptive hash routing for a cluster of client-side web proxies

Tang¹,

Chanson²

2004

Journal of Parallel and Distributed Computing

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Hash routing reduces cache misses for a cluster of web proxies by eliminating the duplication of cache contents. In this paper, we investigate the optimization of hash routing performance by dynamically adapting object and DNS allocations to the traffic pattern. An analytical model is developed for hash routing that takes into consideration the original request distribution, the object allocation strategy, the speeds of the proxies and the cache hit ratios. Based on this model, the optimal hash routing problem is studied. The analytical results are applied to the design of two adaptive hash routing schemes: ADA-OBJ optimizes object allocation under static client configuration, and ADA-OBJ/DNS optimizes both object and DNS allocations under dynamic client configuration. Trace-driven simulation experiments have been conducted to evaluate the performance of the proposed schemes. The results show that they significantly outperform the intuitive static hash routing scheme based only on the speeds of the proxies.

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A Survey of Current Work in Microprogramming

Cited by 6 publications

References 44 publications

Reverse Engineering of Intel Microcode Update Structure

Reverse Engineering of Intel Microcode Update Structure

Reverse Engineering x86 Processor Microcode

Adaptive hash routing for a cluster of client-side web proxies

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