Intel microcode update guidance Aug. 8, 2018

Intel issued a new guide of microcode updates, to mitigate the newly found Spectre variants:
- CVE-2018-3639 – Speculative Store Bypass (SSB) – also known as Variant 4
- CVE-2018-3640 – Rogue System Register Read (RSRE) – also known as Variant 3a

You can read about it here.

Download the Intel August 8, Updated microcode guide.

pietcorus2 said:

306C3 is included also , can not find any download-link !
Your link does not give the download , its only info............

Both links work perfectly, from my end:

INTEL-SA-00115


https://www.intel.com/content/dam/ww...e-guidance.pdf

andyouf said:

Thanks for the links. On the second link, the MCU Recommendations. I am a bit concerned. My CPUID is 306C3 according to InSpectre and other utilities such as CPU-Z. I am updated to 0x24. However, in the MCU guide my CPUID matched the Haswell desktop CPUs and revision codes (but was not listed there). A google search also brings up desktop CPUs for that CPUID. Mine should be CPUID 40661 according to the guide (Haswell H).

Also, it says "new production MCU Rev" is at 0x25 and this is an 8/8 document. Shouldn't the microcode that came after this have updated me to 0x25 instead of 0x24?

First of all a basic question. When did you update to 0x24 and how?

Second. My BIOS was updated in July, by an update provided by hp. That's long before the document date of Aug. 8. If you read the sa-0015 (1st link) you'll see that Intel mentions that updates have been provided to manufacturers as early as May 21. Meaning that this was a work in progress and its outcome was summarized in a document in Aug. 8.

pietcorus2 said:

" Both links work perfectly, from my end: ".............searching ,searching....still no download-link ( only info !) to find !
Can you help me , when clicking on " downloads" ( below the page) , I can not find these items .........

Click on the links, in the post!

Code:

https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00115.html

https://www.intel.com/content/dam/www/public/us/en/documents/sa00115-microcode-update-guidance.pdf

andyouf said:

On 8/22 using the KB4100347 update.

I was just unsure what new production MCU Rev (2nd link) meant. If that was the microcode update in progress maybe.

New production MCU means, the new revision of the μcode you currently need to mitigate the existing known vulnerabilities.
The old one is only for Spectre Variant 2 and Meltdown.
The new is for those 2 plus Rogue System Register Read (RSRE) – a.k.a Variant 3a and Speculative Store Bypass (SSB) – a.k.a Variant 4 and if not mistaken a new one called L1T.