JRS
JRS
Sep 9, 2018 · 1 min read

Yes, for everyone asking, this is a real and severe vulnerability. Very well written article. It explained it in full, but here is a simple explanation.

In layman’s terms:

  1. Kernel memory and User memory are stored together, but separated by permissions. (It has always been this way.)
  2. Processors are optimized to run code ahead of time (and out of order) very often under the hood. This is called “speculative execution.”
  3. Speculative execution on Intel processors does not honor the permissions. (It doesn’t check permissions at all *during speculative execution*.)

That’s the vulnerability. It basically blows the whole OS wide open to attack. It means everything is accessible and exploitable. The more technical details explain *how* to do it, but that is the open door.

It’s so simple and so stupid. You do not have to be a software engineer (or a computer person) to understand this is a complete failure.

TL;DR: Intel CPUs don’t check permissions to sensitive data under the hood, even if though it appears they do on the surface.

    JRS

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    JRS