Category: meltdown

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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Mar 15 2018

Intel outlines plans for Meltdown and Spectre fixes, microcode for older chips

Enlarge / Intel Ivy Bridge Xeon E7 v2 die shot. (credit: Fritzchens Fritz)

Shipping in the second half of this year, the next generation of Xeon Scalable Processors (codenamed Cascade Lake) will contain hardware fixes for the Meltdown attack and certain variants of the Spectre attack. So, too, will a range of processors using the same 8th generation Core branding that some processors are already using.

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.

The Spectre attack has two variants, numbered version 1 and version 2. Spectre version 1 attacks will need software fixes, and the nature of these attacks means that they may always need software fixes. Applications that try to build sandboxes—locked-down environments used for running potentially hostile code, such as JavaScript in the browser—will need to be examined and updated to provide robust protection against Spectre version 1.

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Mar 13 2018

Patch Tuesday drops the mandatory antivirus requirement after all

(credit: amalthya / Flickr)

In the immediate aftermath of the Spectre and Meltdown attacks, Microsoft created an unusual stipulation for Windows patches: systems would only receive the fixes if they had antivirus software installed and if that antivirus software created a special entry in the registry to indicate that it's compatible with the Windows fixes.

This was due to the particularly invasive nature of the Meltdown fix: Microsoft found that certain antivirus products manipulated Windows' kernel memory in unsupported ways that would crash systems with the Meltdown fix applied. The registry entry was a way for antivirus software to positively affirm that it was compatible with the Meltdown fix; if that entry was absent, Windows assumed that incompatible antivirus software was installed and hence did not apply the security fix.

This put systems without any antivirus software at all in a strange position: they too lack the registry entries, so they'd be passed over for fixes, even though they don't, in fact, have any incompatible antivirus software.

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