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Retbleed
Retbleed is a speculative execution attack on x86-64 and ARM processors, including some recent Intel and AMD chips. First made public in 2022, it is a variant of the Spectre vulnerability which exploits retpoline, which was intended as a mitigation for speculative execution attacks. According to the researchers Retbleed mitigations require extensive changes to the system which results in up to 14% and 39% performance loss on Linux for affected AMD and Intel CPU respectively. The PoC works against Intel Core 6th, 7th and 8th generation microarchitectures and AMD Zen 1, Zen 1+, and Zen 2 microarchitectures. An official document from ARM informs that all ARM CPUs affected by Spectre are also affected by Retbleed. Windows is not vulnerable because the existing mitigations already tackle it. Linux kernels 5.18.14 and 5.19 contain the fixes. The 32-bit Linux kernel, which is vulnerable, will not receive updates to fix the issue. References External links Retbleed: Arbitrary Sp ...
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Speculative Execution
Speculative execution is an optimization technique where a computer system performs some task that may not be needed. Work is done before it is known whether it is actually needed, so as to prevent a delay that would have to be incurred by doing the work after it is known that it is needed. If it turns out the work was not needed after all, most changes made by the work are reverted and the results are ignored. The objective is to provide more concurrency if extra resources are available. This approach is employed in a variety of areas, including branch prediction in pipelined processors, value prediction for exploiting value locality, prefetching memory and files, and optimistic concurrency control in database systems.Lazy and Speculative Execution

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X86-64
x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit version of the x86 instruction set, first released in 1999. It introduced two new modes of operation, 64-bit mode and compatibility mode, along with a new 4-level paging mode. With 64-bit mode and the new paging mode, it supports vastly larger amounts of virtual memory and physical memory than was possible on its 32-bit predecessors, allowing programs to store larger amounts of data in memory. x86-64 also expands general-purpose registers to 64-bit, and expands the number of them from 8 (some of which had limited or fixed functionality, e.g. for stack management) to 16 (fully general), and provides numerous other enhancements. Floating-point arithmetic is supported via mandatory SSE2-like instructions, and x87/ MMX style registers are generally not used (but still available even in 64-bit mode); instead, a set of 16 vector registers, 128 bits each, is used. (Each register can store one or two double- ...
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ARM Architecture Family
ARM (stylised in lowercase as arm, formerly an acronym for Advanced RISC Machines and originally Acorn RISC Machine) is a family of reduced instruction set computer (RISC) instruction set architectures for computer processors, configured for various environments. Arm Ltd. develops the architectures and licenses them to other companies, who design their own products that implement one or more of those architectures, including system on a chip (SoC) and system on module (SOM) designs, that incorporate different components such as memory, interfaces, and radios. It also designs cores that implement these instruction set architectures and licenses these designs to many companies that incorporate those core designs into their own products. There have been several generations of the ARM design. The original ARM1 used a 32-bit internal structure but had a 26-bit address space that limited it to 64 MB of main memory. This limitation was removed in the ARMv3 series, which ha ...
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Intel
Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 series of instruction sets, the instruction sets found in most personal computers (PCs). Delaware General Corporation Law, Incorporated in Delaware, Intel ranked No. 45 in the 2020 Fortune 500, ''Fortune'' 500 list of the largest United States corporations by total revenue for nearly a decade, from 2007 to 2016 fiscal years. Intel supplies microprocessors for List of computer system manufacturers, computer system manufacturers such as Acer Inc., Acer, Lenovo, HP Inc., HP, and Dell Technologies, Dell. Intel also manufactures motherboard chipsets, network interface controllers and integrated circuits, flash memory, Graphics processing unit, graphics chips, Embedded system, embedded processors and other devices related to com ...
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Spectre (security Vulnerability)
Spectre refers to one of the two original transient execution CPU vulnerabilities (the other being Meltdown), which involve microarchitectural timing side-channel attacks. These affect modern microprocessors that perform branch prediction and other forms of speculation. On most processors, the speculative execution resulting from a branch misprediction may leave observable side effects that may reveal private data to attackers. For example, if the pattern of memory accesses performed by such speculative execution depends on private data, the resulting state of the data cache constitutes a side channel through which an attacker may be able to extract information about the private data using a timing attack. Two Common Vulnerabilities and Exposures IDs related to Spectre, (bounds check bypass, Spectre-V1, Spectre 1.0) and (branch target injection, Spectre-V2), have been issued. JIT engines used for JavaScript were found to be vulnerable. A website can read data stor ...
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Retpoline
Spectre refers to one of the two original transient execution CPU vulnerabilities (the other being Meltdown), which involve microarchitectural timing side-channel attacks. These affect modern microprocessors that perform branch prediction and other forms of speculation. On most processors, the speculative execution resulting from a branch misprediction may leave observable side effects that may reveal private data to attackers. For example, if the pattern of memory accesses performed by such speculative execution depends on private data, the resulting state of the data cache constitutes a side channel through which an attacker may be able to extract information about the private data using a timing attack. Two Common Vulnerabilities and Exposures IDs related to Spectre, (bounds check bypass, Spectre-V1, Spectre 1.0) and (branch target injection, Spectre-V2), have been issued. JIT engines used for JavaScript were found to be vulnerable. A website can read data stored in ...
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ETH Zurich
(colloquially) , former_name = eidgenössische polytechnische Schule , image = ETHZ.JPG , image_size = , established = , type = Public , budget = CHF 1.896 billion (2021) , rector = Günther Dissertori , president = Joël Mesot , academic_staff = 6,612 (including doctoral students, excluding 527 professors of all ranks, 34% female, 65% foreign nationals) (full-time equivalents 2021) , administrative_staff = 3,106 (40% female, 19% foreign nationals, full-time equivalents 2021) , students = 24,534 (headcount 2021, 33.3% female, 37% foreign nationals) , undergrad = 10,642 , postgrad = 8,299 , doctoral = 4,460 , other = 1,133 , address = Rämistrasse 101CH-8092 ZürichSwitzerland , city = Zürich , coor = , campus = Urban , language = German, English (Masters and upwards, sometimes Bachelor) , affiliations = CESAER, EUA, GlobalTech, IARU, IDEA League, UNITECH , website ethz.ch, colors = Black and White , logo = ETH Zürich Logo black.svg ETH Z� ...
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Proof Of Concept
Proof of concept (POC or PoC), also known as proof of principle, is a realization of a certain method or idea in order to demonstrate its feasibility, or a demonstration in principle with the aim of verifying that some concept or theory has practical potential. A proof of concept is usually small and may or may not be complete. These collaborative trials aim to test feasibility of business concepts and proposals to solve business problems and accelerate business innovation goals. A proof of value (PoV) is sometimes used along proof of concept, and differs by focusing more on demonstrating the potential customers use case and value, and is usually less in-depth than a proof of concept. Usage history The term has been in use since 1967. In a 1969 hearing of the Committee on Science and Astronautics, Subcommittee on Advanced Research and Technology, ''proof of concept'' was defined as following: One definition of the term "proof of concept" was by Bruce Carsten in the context ...
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Intel Core
Intel Core is a line of streamlined midrange consumer, workstation and enthusiast computer central processing units (CPUs) marketed by Intel Corporation. These processors displaced the existing mid- to high-end Pentium processors at the time of their introduction, moving the Pentium to the entry level. Identical or more capable versions of Core processors are also sold as Xeon processors for the server and workstation markets. The lineup of Core processors includes the Intel Core i3, Intel Core i5, Intel Core i7, and Intel Core i9, along with the X-series of Intel Core CPUs. Outline Although Intel Core is a brand that promises no internal consistency or continuity, the processors within this family have been, for the most part, broadly similar. The first products receiving this designation were the Core Solo and Core Duo Yonah processors for mobile from the Pentium M design tree, fabricated at 65 nm and brought to market in January 2006. These are substantial ...
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Zen (microarchitecture)
Zen is the codename for a family of computer processor microarchitectures from AMD, first launched in February 2017 with the first generation of its Ryzen CPUs. It is used in Ryzen (desktop and mobile), Ryzen Threadripper (workstation/high end desktop), and Epyc (server). Comparison History First generation The first generation Zen was launched with the Ryzen 1000 series of CPUs (codenamed Summit Ridge) in February 2017. The first Zen-based preview system was demonstrated at E3 2016, and first substantially detailed at an event hosted a block away from the Intel Developer Forum 2016. The first Zen-based CPUs reached the market in early March 2017, and Zen-derived Epyc server processors (codenamed "Naples") launched in June 2017 and Zen-based APUs (codenamed "Raven Ridge") arrived in November 2017. This first iteration of Zen utilized Global Foundries' 14 nm manufacturing process. First generation refresh Zen+ was first released in April 2018, powering the se ...
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Microsoft Windows
Windows is a group of several Proprietary software, proprietary graphical user interface, graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for servers, and Windows IoT for embedded systems. Defunct Windows families include Windows 9x, Windows Mobile, and Windows Phone. The first version of Windows was released on November 20, 1985, as a graphical operating system shell for MS-DOS in response to the growing interest in graphical user interfaces (GUIs). Windows is the most popular desktop operating system in the world, with Usage share of operating systems, 75% market share , according to StatCounter. However, Windows is not the most used operating system when including both mobile and desktop OSes, due to Android (operating system), Android's massive growth. , the most recent version of Windows is Windows 11 for consumer Personal compu ...
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Linux Kernel
The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU operating system, which was written to be a free (libre) replacement for Unix. Linux is provided under the GNU General Public License version 2 only, but it contains files under other compatible licenses. Since the late 1990s, it has been included as part of a large number of operating system distributions, many of which are commonly also called Linux. Linux is deployed on a wide variety of computing systems, such as embedded devices, mobile devices (including its use in the Android operating system), personal computers, servers, mainframes, and supercomputers. It can be tailored for specific architectures and for several usage scenarios using a family of simple commands (that is, without the need of manually editing its source c ...
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