Spectre

Spectre

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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, CVE-2017-5753 (bounds check bypass, Spectre-V1, Spectre 1.0) and CVE-2017-5715 (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 the browser for another website, or the browser's memory itself.

In early 2018, Intel reported that it would redesign its CPUs to help protect against the Spectre and related Meltdown vulnerabilities (especially, Spectre variant 2 and Meltdown, but not Spectre variant 1).
On 8 October 2018, Intel was reported to have added hardware and firmware mitigations regarding Spectre and Meltdown vulnerabilities to its latest processors.

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