Intel has disclosed vulnerabilities called Microarchitectural Data Sampling (MDS) that apply to desktop and notebook computers with Intel CPUs, including all modern Mac computers.

You can check if hyper-threading is enabled or disabled in the System Information app. Just choose Apple menu  > About This Mac, then click the System Report button. Then select Hardware in the sidebar. If the processor in your Mac supports hyper-threading, Hyper-Threading Technology is shown as either Enabled or Disabled.

Although there are no known exploits affecting customers at the time of this writing, customers who believe their computer is at heightened risk of attack can use the Terminal app to enable an additional CPU instruction and disable hyper-threading processing technology, which provides full protection from these security issues.

This option is available for macOS Mojave, High Sierra and Sierra and may have a significant impact on the performance of your computer.

The full mitigation, which includes disabling hyper-threading, prevents information leakage across threads and when transitioning between kernel and user space, which is associated with the MDS vulnerabilities for both local and remote (web) attacks.

Testing conducted by Apple in May 2019 showed as much as a 40 percent reduction in performance with tests that include multithreaded workloads and public benchmarks. Performance tests are conducted using specific Mac computers. Actual results will vary based on model, configuration, usage, and other factors.

How to enable full mitigation for MDS in macOS and how to revert the mitigation and reenable hyper-threading via Apple Support here.

MacDailyNews Take: Apple can’t begin to dump feckless Intel’s defective chips soon enough! It’s time to start moving Macs to vastly more efficient and secure Apple-designed solutions.

When flawed, insecure, and therefore defective products are sold to consumers, recalls and/or recompense are the proper responses.MacDailyNews, January 4, 2018

SEE ALSO:
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Researchers reveal new ‘Spoiler’ vulnerability in all Intel Core processors – March 6, 2019
Intel discloses new ‘Variant 3a’ and ‘Variant 4’ Spectre-like chip flaw vulnerabilities – May 22, 2018
Intel’s Spectre patch is causing reboot problems – January 12, 2018
In wake of Spectre and Meltdown, Intel CEO offers open letter, looks to restore confidence in Intel CPU security – January 11, 2018
Apple releases iOS and macOS updates with a mitigation for Spectre CPU flaw – January 8, 2018
Meltdown and Spectre: What Apple users need to know – January 8, 2018
How Apple product users can protect themselves against Spectre and Meltdown CPU flaws – January 5, 2018
Intel’s CEO Brian Krzanich sold off the majority of his shares after finding out about the irreparable chip flaws – January 4, 2018
Apple: All Mac systems and iOS devices are affected by Meltdown and Spectre security flaws – January 4, 2018
CERT: Only way to fix Meltdown and Spectre vulnerabilities is to replace CPU – January 4, 2018
Security flaws put nearly every modern computing device containing chips from Intel, AMD and ARM at risk – January 4, 2018
Apple has already partially implemented fix in macOS for ‘KPTI’ Intel CPU security flaw – January 3, 2018
Intel’s massive chip flaw could hit Mac where it hurts – January 3, 2018