New Intel CPU bug
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farne




Posts: 3732

PostPosted: Fri, 24th Aug 2018 14:29    Post subject: New Intel CPU bug
https://marc.info/?l=openbsd-tech&m=153504937925732&w=2

Quote:

Two recently disclosed hardware bugs affected Intel cpus:

- TLBleed

- T1TF (the name "Foreshadow" refers to 1 of 3 aspects of this
bug, more aspects are surely on the way)

Solving these bugs requires new cpu microcode, a coding workaround,
*AND* the disabling of SMT / Hyperthreading.

SMT is fundamentally broken because it shares resources between the two
cpu instances and those shared resources lack security differentiators.
Some of these side channel attacks aren't trivial, but we can expect
most of them to eventually work and leak kernel or cross-VM memory in
common usage circumstances, even such as javascript directly in a
browser.

There will be more hardware bugs and artifacts disclosed. Due to the
way SMT interacts with speculative execution on Intel cpus, I expect SMT
to exacerbate most of the future problems.

A few months back, I urged people to disable hyperthreading on all
Intel cpus. I need to repeat that:

DISABLE HYPERTHREADING ON ALL YOUR INTEL MACHINES IN THE BIOS.

Also, update your BIOS firmware, if you can.

OpenBSD -current (and therefore 6.4) will not use hyperthreading if it
is enabled, and will update the cpu microcode if possible.

But what about 6.2 and 6.3?

The situation is very complex, continually evolving, and is taking too
much manpower away from other tasks. Furthermore, Intel isn't telling
us what is coming next, and are doing a terrible job by not publically
documenting what operating systems must do to resolve the problems. We
are having to do research by reading other operating systems. There is
no time left to backport the changes -- we will not be issuing a
complete set of errata and syspatches against 6.2 and 6.3 because it is
turning into a distraction.

Rather than working on every required patch for 6.2/6.3, we will
re-focus manpower and make sure 6.4 contains the best solutions
possible.

So please try take responsibility for your own machines: Disable SMT in
the BIOS menu, and upgrade your BIOS if you can.

I'm going to spend my money at a more trustworthy vendor in the future.


Intel hiring an ((((israeli security company)))) to smear AMD in 3... 2... 1.
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paxsali
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Posts: 18352

PostPosted: Fri, 24th Aug 2018 15:00    Post subject:
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Last edited by paxsali on Thu, 4th Jul 2024 23:26; edited 2 times in total
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Areius




Posts: 14855

PostPosted: Fri, 24th Aug 2018 15:13    Post subject:
Repost from CPU thread.

But all these bugs can affect your desktop as well, some Javascript implementations of the previous bugs exists (likely that this will be possible as well). So rogue sites can read your data while you're just browsing and, for example, capture your passwords. All very serious bugs. AMD seems mostly unaffected by all these bugs, but I'm still running my rusty old 2500k, which with all these patches seem to become closer to my old AMD Athlon XP 2500+ Laughing


PC: Yes. Console: No.
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paxsali
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Posts: 18352

PostPosted: Fri, 24th Aug 2018 16:31    Post subject:
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Last edited by paxsali on Thu, 4th Jul 2024 23:26; edited 2 times in total
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Nui
VIP Member



Posts: 5720
Location: in a place with fluffy towels
PostPosted: Fri, 24th Aug 2018 18:17    Post subject:
@ pax
do you have sources for any of your claims?

like security being irrelevant because your data is stolen anyway (except it is relevant when its not your machine but someone elses?), or amd being affected the same way.


kogel mogel
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Areius




Posts: 14855

PostPosted: Fri, 24th Aug 2018 19:58    Post subject:
paxsali wrote:

You think rogue sites can't or won't read your data when you don't have no intel bug of the type that's relevant here? Laughing

Ehm, no, normally data is sandboxed per site, there might be some cookies leaked here and there but that's about it. The problem is that with these bugs is that they can get access to data outside of this sandbox. Rogue sites are then able to read data of your banking accounts for example. So these bugs are very bad and could affect everyone. Unless you don't have your PC connected to the web of course, but that's not very likely to be the case Smile

There's several js versions for Spectre for example, such as this:
https://github.com/ascendr/spectre-chrome


PC: Yes. Console: No.
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paxsali
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Posts: 18352

PostPosted: Fri, 24th Aug 2018 22:10    Post subject:
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paxsali
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Posts: 18352

PostPosted: Fri, 24th Aug 2018 22:21    Post subject:
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