Critical Update to Disable Mitigation against Spectre, Variant 2
Applies to: Windows 7 Service Pack 1, Windows 8.1, Windows 10, Windows 10 Version 1511, Windows 10 Version 1607, Windows 10 Version 1703, Windows 10 version 1709, Windows Server 2008 R2 Standard, Windows Server 2012 R2 Standard
Summary
Intel has
reported issues with recently released microcode meant to address Spectre variant 2 (CVE 2017-5715 Branch Target Injection) – specifically Intel noted that this microcode can cause “
higher than expected reboots and other unpredictable system behavior” and then noted that situations like this may result in “
data loss or corruption.” Our own experience is that system instability can in some circumstances cause data loss or corruption. On January 22nd Intel recommended that customers
stop deploying the current microcode version on impacted processors while they perform additional testing on the updated solution. We understand that Intel is continuing to investigate the potential impact of the current microcode version and encourage customers to review their guidance on an ongoing basis to inform their decisions.
While Intel tests, updates and deploys new microcode, we are making available an out of band update today, KB4078130, that specifically disables only the mitigation against CVE-2017-5715 – “Branch target injection vulnerability.” In our testing this update has been found to prevent the behavior described. For the full list of devices, see
Intel’s microcode revision guidance. This update covers Windows 7 (SP1), Windows 8.1, and all versions of Windows 10, for client and server. If you are running an impacted device, this update can be applied by downloading it from the Microsoft Update Catalog
website. Application of this payload specifically disables only the mitigation against CVE-2017-5715 – “Branch target injection vulnerability.”
Note Users who do not have the affected Intel microcode do not have to download this update.
We are also offering a new option – available for advanced users on impacted devices – to manually disable and enable the mitigation against Spectre Variant 2 (CVE 2017-5715) independently via registry setting changes. The instructions for the registry key settings can be found in the following two Knowledge Base articles:
As of January 25, there are no known reports to indicate that this Spectre variant 2 (CVE 2017-5715 ) has been used to attack customers. We recommend Windows customers, when appropriate, reenable the mitigation against CVE-2017-5715 when Intel reports that this unpredictable system behavior has been resolved for your device.
How to get this update
Microsoft Update Catalog
To get the stand-alone package for this update, go to the
Microsoft Update Catalog website.
More Information
Known issues in this update
Microsoft is not aware of any issues that affect this update currently.
Prerequisites
There are no prerequisites to apply this update.
Registry information
To apply this update, you don't have to make any changes to the registry.
Restart requirement
You will have to restart the computer after you apply this update.
Update replacement information
This update does not replace a previously released update.
Download KB4078130 MSU for Windows 10, Windows 10 LTSB, Windows 7, Windows 8.1, Windows Embedded Standard 7, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012 R2, Windows Server 2016 - 24 KB
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