Why wouldn't security flaw affect AMD processor?

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According to this news article there's a newly found security flaw in processors. However, the article also claims that it only may affect Intel processors and not AMD ones. I thought they were using the same architecture, how come it would only affect one brand?

Nae

Posted 2018-01-03T16:40:21.080

Reputation: 171

1That only means they support the same instruction set. The underlying implementations are very different. – user1686 – 2018-01-03T16:58:30.683

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See the main reason: https://lkml.org/lkml/2017/12/27/2

– Biswapriyo – 2018-01-03T17:01:31.057

Answers

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The issue has nothing to do with the architecture itself. Intel and AMD processers have very different implementations and feature sets while still conforming to the desired architecture.

multithr3at3d

Posted 2018-01-03T16:40:21.080

Reputation: 516

2Good example of a difference that got Microsoft is the old original Microsoft Xbox 1. The Xbox 1 was able to be hacked because the Intel CPU in that system (at that time at least) wraps around back to adderss 0 when it reaches the last address, whereas the AMD CPU that was being considered (but was ultimately not decided on) generated an exception. The wraparound allowed exploit code to be placed at a convenient spot and was instrumental in allowing the MechAssault and other softmods to exist. – LawrenceC – 2018-01-03T16:56:14.143

2While Intel and AMD processors both comply with the x86 Architecture, as pointed out, the amount of time a specific instruction takes to complete can be different. Intel and AMD also have brand-specific instructions, and they might or might not have equivalent instructions (i.e. VT-x vs AMD-V), depends on the instruction. The detail of the exploit has not been released, due to an embargo on the specifics, without knowing the vulnerable instruction involved this question is difficult to answer in more detail. – Ramhound – 2018-01-03T17:04:14.087

It also might be worth pointing out the flaw appears, based on Intel's claim, to actually apply to AMD and ARM processors also.

– Ramhound – 2018-01-03T22:22:46.920

@ramhound - Intel is being a bit disengenius with their insinuation. AMD x86 cpus are not affected - however, AMD also do ARM processors, and ARM processors are affected. – davidgo – 2018-01-03T23:54:16.027

@davidgo Let is wait for the details of the vulnerability before we say that. With an embargo on the details we don’t have a great deal of third-party confirmation from anyone without an agenda. – Ramhound – 2018-01-04T00:00:10.127

@ramhound - I don't think the Linux kernel guys have an agenda - and they do know the details and have exempted and x86 -http://lkml.iu.edu/hypermail/linux/kernel/1712.3/00675.html

– davidgo – 2018-01-04T00:07:36.413

1“Everyone is at risk” only one of the vulnerabilities was apparently fixed – Ramhound – 2018-01-04T01:10:31.053