Intel recently confirmed that its Spectre Variant 2 security update was causing issues on a number of hardware configurations, and this triggered a quick reaction from the rest of the industry, which had no other choice than to pull their own updates until a fix is offered.

With Intel’s own patches also included in Microsoft’s security updates for Windows, the Redmond-based software giant made the obvious call and decided to disable the Spectre Variant 2 patch as well, explaining in an advisory that all versions of the operating system are affected.

A new update labeled as KB4078130 is supposed to disable mitigation against Spectre Variant 2, and Microsoft also provides guidance to disable and enable this patch manually via the registry.

“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,’” Microsoft explains.

The company says that it’s not aware of any attacks aimed at the Spectre Variant 2 vulnerability, and explains that it’s waiting for Intel to deliver a fix in order to re-enable its own mitigation for Windows users.

“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,” the firm says.

Enable and disable Spectre Variant 2 mitigation manually

Microsoft also provides the following registry settings for user who want to enable or disable the Spectre Variant 2 without deploying KB4078130 on their systems:

To enable Variant 2: CVE 2017-5715 “Branch Target Injection”:

reg add “HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession ManagerMemory Management” /v FeatureSettingsOverride /t REG_DWORD /d 0 /f

reg add “HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession ManagerMemory Management” /v FeatureSettingsOverrideMask /t REG_DWORD /d 1 /f

To disable Variant 2: CVE 2017-5715″Branch Target Injection”:

reg add “HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession ManagerMemory Management” /v FeatureSettingsOverride /t REG_DWORD /d 1 /f

reg add “HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSession ManagerMemory Management” /v FeatureSettingsOverrideMask /t REG_DWORD /d 1 /f

KB4078130 isn’t shipped via Windows Update, and can only be downloaded for Windows 7, 8.1, and 10 from the Update Catalog here.

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