Microsoft Issues Windows Out-of-Band Update That Disables Spectre Mitigations

An anonymous reader quotes BleepingComputer: Microsoft has issued on Saturday an emergency out-of-band Windows update that disables patches for the Spectre Variant 2 bug (CVE-2017-5715). The update -- KB4078130 -- targets Windows 7 (SP1), Windows 8.1, all versions of Windows 10, and all supported Windows Server distributions. Microsoft shipped mitigations for the Meltdown and Spectre bugs on January 3. The company said it decided to disable mitigations for the Spectre Variant 2 bug after Intel publicly admitted that the microcode updates it developed for this bug caused "higher than expected reboots and other unpredictable system behavior" that led to "data loss or corruption." HP, Dell, and Red Hat took previous steps during the past week.

"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..." Microsoft writes. "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. "