Apr 11 2018

AMD systems gain Spectre protection with latest Windows fixes

Enlarge / An AMD Ryzen. (credit: Fritzchens Fritz)

The latest Windows 10 fixes, released as part of yesterday's Patch Tuesday, enable protection against the Spectre variant 2 attacks on systems with AMD processors.

Earlier this year, attacks that exploit the processor's speculative execution were published with the names Meltdown and Spectre, prompting a reaction from hardware and software companies. AMD chips are immune to Meltdown but have some vulnerability to the two Spectre variants. Spectre variant 1 requires application-level fixes; variant 2 requires operating system-level alterations.

Both Intel and AMD have released microcode updates to alter their processor behavior to give operating systems the control necessary to protect against Spectre variant 2. Microsoft has been shipping the Intel microcode, along with the operating system changes necessary to use the microcode's new features, for several weeks now; with yesterday's patch, similar protections are now enabled on AMD machines.

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Mar 26 2018

It’s not just Spectre: Researchers reveal more branch prediction attacks

Enlarge (credit: Ed Dunens)

Researchers from the College of William and Mary, Carnegie Mellon, the University of California Riverside, and Binghamton University have described a security attack that uses the speculative execution features of modern processors to leak sensitive information and undermine the security boundaries that operating systems and software erect to protect important data.

That probably sounds familiar.

The Spectre attacks, published earlier this year, take advantage of the speculative execution features of modern processors to leak sensitive information. The new attack, named BranchScope by the researchers, shares some similarity with variant 2 of the Spectre attack, as both BranchScope and Spectre 2 take advantage of the behavior of the processor's branch predictor.

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Feb 21 2018

Intel ships (hopefully stable) microcode for Skylake, Kaby Lake, Coffee Lake

Enlarge / Intel Core i9 X-series Skylake X. (credit: Intel)

Intel reports that it has developed a stable microcode update to address the Spectre flaw for its Skylake, Kaby Lake, and Coffee Lake processors in all their various variants.

The microcode updates help address Spectre variant 2 attacks. Spectre variant 2 attacks work by persuading a processor's branch predictor to make a specific bad prediction about which code will be executed. This bad prediction can then be used to infer the value of data stored in memory, which, in turn, gives an attacker information that they shouldn't otherwise have. The microcode update is designed to give operating systems greater control over the branch predictor, enabling them to prevent one process from influencing the predictions made in another process.

Intel's first microcode update, developed late last year, was included in system firmware updates for machines with Broadwell, Haswell, Skylake, Kaby Lake, and Coffee Lake processors. But users subsequently discovered that the update was causing systems to crash and reboot. Initially, only Broadwell and Haswell systems were confirmed to be affected, but further examination determined that Skylake, Kaby Lake, and Coffee Lake systems were rebooting, too.

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Feb 07 2018

Intel releases new Spectre microcode update for Skylake; other chips remain in beta

Enlarge / Intel Skylake Core i7-6700K. (credit: Orestis Bastounis)

After recommending customers not use its microcode fix for Broadwell and Haswell chips, Intel has issued a new microcode update for Skylake processors that gives operating systems the ability to protect against the Spectre flaw revealed earlier this year.

The Spectre attacks work by persuading the processor's branch predictor into making a specific bad prediction. This bad prediction can then be used to infer the value of data stored in memory, in turn giving an attacker information that they shouldn't otherwise have. The microcode update is designed to give operating systems greater control over the branch predictor, enabling them to prevent one process from influencing the predictions made in another process.

Intel's first microcode update, developed late last year, was included in system firmware updates for machines with Broadwell, Haswell, Skylake, Kaby Lake, and Coffee Lake processors. It was subsequently discovered that the update was causing systems to crash and reboot; initially, only Broadwell and Haswell systems were confirmed to be affected, but subsequently it was determined that Skylake, Kaby Lake, and Coffee Lake systems were rebooting too. In response, people were advised not to use the new microcode, and operating system features that leveraged the new capabilities were disabled.

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