Pretty sure that its not limited to js:

https://gist.github.com/ErikAugust/724d4a969fb2c6ae1bbd7b2a9...

Its a technique, not a flaw in js, from my understanding

This PoC is implemented in js, but my point stands regardless of the language used. It requires code executing on the same physical server as your app in order to be an issue for you. Similar to a hypervisor escape (since we're being pedantic yes, I understand this is not a hypervisor escape), the evil neighbor surface is not present if you have no neighbors.

I don't think you understand the bug here.

1) https://spectreattack.com/: "Spectre tricks other applications into accessing arbitrary locations in their memory. " Spectre does not let you execute code in another guest

2) Spectre is not javascript specific. I am not sure why you think it is, beyond the fact a PoC was written in js

I don't think you understand my point. You should reread my post, especially the first sentence. It's first and alone for a reason; not sharing hardware is an effective mitigation against vulnerabilities in shared hardware.

Obviously it's not just a js bug, there are other PoCs in other languages.

I never said anything about executing code in another guest, not sure where you got that from.

>Pretty hard to have a neighbor vm execute Spectre on your same physical server if you have dedicated hardware.

You have no reason to care about a neighbor VM executing Spectre on the same physical server, since they're only hurting themselves, not you.

>Add in that Spectre specifically is a js bug so in order to be vulnerable your server would need to execute untrusted JavaScript and I think we can assume the threat surface of this specific bug is smaller outside the cloud...

"Spectre specifically is a js bug"

Spectre is exploitable from processes, not just containers.... containers are equivalent to processes from it's point-of-view as the kernel is shared.

So... you may be able to go native to avoid having neighbours, but this does not prevent other processes exploiting your process. To do that you need to prevent any downloadable code from running.

This of course is possible and is the entire reason why the ARM document explains that most embedded systems are not affected due to the fact that they will not download and execute code (of any form).