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Massive security hole in CPU's incoming?Official Meltdown/Spectre Discussion Thread

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Hitman928

Diamond Member
Apr 15, 2012
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I'm not engineer and don't know how critical this Ring vulnerability is, but it sounds like it only affect Intel because of Ring. Is it fixable via bios update? Don't tell me this would lead to some other bit of performance lost......
They couldn't 'fix' this with a BIOS update. They may be able to mitigate it to some degree, but it will have some sort of performance penalty associated with it.
 

DrMrLordX

Lifer
Apr 27, 2000
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The exploit relies on the ring bus protocol itself. Can they even modify that behavior with microcode updates?
 

moinmoin

Platinum Member
Jun 1, 2017
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Looks like it uses some instruction code previously used by AMD's 3DNow! extension. I guess having some software already use an instruction Intel never acknowledged makes for a good camouflage for new instructions of this kind. Security by obscurity at its finest...
 
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chris george

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https://pythonsweetness.tumblr.com%2Fpost%2F169166980422


Quoted from a reddit thread.

This could be big. Many a sysadmin might have sleepless nights soon enough.

EDIT: Since news and clarification arrived, I'll add it here.
Official website with details: https://meltdownattack.com
TL;DR
There are two attacks exploiting similar ideas, called Meltdown and Spectre.

Meltdown affects all Intel CPU's going back a decade, and some select ARM CPU's. It is the more pressing issue of the two, and potentially compromises systems completely due to its power. Patches already went out on both Linux and Windows to mitigate it. Performance hit depends on workload, gaming not noticeably affected.

Spectre affects all CPU's aside from specialized microcontrollers and other low powered devices. It is harder to exploit but also harder to fix. The full consequences and effects of it are still unknown, but all major tech companies are taking steps to research and mitigate it.

Intel Press Release: https://newsroom.intel.com/news/intel-responds-to-security-research-findings/

AMD Press Release: https://www.amd.com/en/corporate/speculative-execution

Apple Press Release: https://support.apple.com/en-us/HT208394

ARM Press Release: https://developer.arm.com/support/security-update



Updated title of the thread to include other CPU companies.


esquared
Anandtech Forum Director
good info
 

ondma

Platinum Member
Mar 18, 2018
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It should be pointed out, this vulnerability affect *both* AMD (since 2017) and Intel (since 2011).
 

Hitman928

Diamond Member
Apr 15, 2012
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I don't have time to go through the paper right now but if the following from the article is true:

Fortunately, the exploitation of micro-op cache vulnerabilities is believed to require a high level of access to the target system, which standard security systems can prevent.
Then it's basically much ado about nothing, more academic interest than a real world threat.
 
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moinmoin

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I don't have time to go through the paper right now but if the following from the article is true:

Then it's basically much ado about nothing, more academic interest than a real world threat.
There is an update to the article stating:
The University of Virginia reached out to us to emphasize that the vulnerabilities are exploitable and should be mitigated against, even if the risk posed isn’t imminent. The researchers intend to collaborate with AMD and Intel and the wider cybersecurity community to overcome the "significant challenges" relating to the performance penalties of the mitigations.
In general it's always a good idea to mitigate potential problems since while they may be hard to exploit now that's rather likely to change in the future.

From the news post by the university:
The new Spectre variants Venkat’s team discovered even break the context-sensitive fencing mechanism outlined in Venkat’s award-winning paper.

Direct link to the paper: https://www.cs.virginia.edu/~av6ds/papers/isca2021a.pdf
 

Hitman928

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Apr 15, 2012
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There is an update to the article stating:


In general it's always a good idea to mitigate potential problems since while they may be hard to exploit now that's rather likely to change in the future.

From the news post by the university:


Direct link to the paper: https://www.cs.virginia.edu/~av6ds/papers/isca2021a.pdf
Mitigation is always going to be recommended by the security researchers, but in reality, I doubt it will be done if you have to have direct access / elevated permissions on the machine to begin with as suggested by the techspot article. Not if the performance penalties are as severe as they are suggesting.
 
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DrMrLordX

Lifer
Apr 27, 2000
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moinmoin

Platinum Member
Jun 1, 2017
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Linux updates. Irrelevant to most.
That's wrong. Linux distributions updating microcode is easier to follow and more transparent than under other OSes like Windows. But said microcode is independent from the OS and distributed as part of updates under all OSes.
 

AdamK47

Lifer
Oct 9, 1999
13,591
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That's wrong. Linux distributions updating microcode is easier to follow and more transparent than under other OSes like Windows. But said microcode is independent from the OS and distributed as part of updates under all OSes.
Show me the impact to Windows users.
 

Hitman928

Diamond Member
Apr 15, 2012
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Somewhat of a vulnerability. Malware can tell if it is put into a sandbox environment on Intel CPUs which would allow it to stop executing or alter behavior, making it harder for researchers to figure out what the malware does.

 

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