Questions tagged [meltdown]

A side-channel vulnerability affecting Intel x86 and few ARM-based microprocessors allowing user processes to read memory belonging to the kernel. Affects various OSes like Linux, OS X, and Windows. Published in January 2018.

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Meltdown and Spectre Attacks

Canonical question regarding the 2018 Jan. disclosed Meltdown and Spectre Attacks. Other identical or significantly similar questions should be closed as a duplicate of this one. Main concerns What ...
M'vy's user avatar
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Meltdown and Virtual Machines

This question originated from a discussion about VMs not being vulnerable to Meltdown. Can Meltdown "break out" of a virtual machine, so to speak? What is meant by this is: Can a program (with any ...
NH.'s user avatar
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Why do CPUs operate speculatively with results of forbidden memory fetches?

By my understanding, the Meltdown and Spectre attacks both exploit the fact that some modern processor, when given something like: if (x < arr1[y]) z = arr2[arr3[x]*256]; may sometimes fetch ...
supercat's user avatar
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Should Virtual Machines be patched for Meltdown and Spectre?

In Meltdown and Virtual Machines it was clarified that at least Spectre works crossing VMs. This of course means that the Hypervisor must be patched, but Should the VM OS be patched as well? Not ...
Envite's user avatar
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8 votes
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Intel firmware/microcode updates that make processors "immune" to both Spectre and Meltdown?

Recently Intel has claimed the following in a press release (emphasis added): SANTA CLARA, Calif., Jan. 4, 2018 — Intel has developed and is rapidly issuing updates for all types of Intel-based ...
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How does the side channel actually access the contents of kernel memory in Meltdown?

In the Meltdown paper it mentions it can identify kernel memory address being accessed. The part I don't understand is how the FLUSH+RELOAD channel works to identify what the contents of the memory ...
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Is there a microcode or other hardware fix for Meltdown?

Linked to my question here, the MS support page states In addition to installing the January security update, a processor microcode update is required. But previous articles I've read said ...
Darren's user avatar
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68 votes
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What are the risks of not patching a server or hypervisor for Meltdown?

The patch for Meltdown is rumoured to incur a 30% performance penalty, which would be nice to avoid if possible. So this becomes a Security vs Performance risk-assessment problem. I am looking for a ...
Mike Ounsworth's user avatar
48 votes
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How to mitigate Meltdown in Docker images?

On it is suggested that (in some cases?) scenarios with Docker containers are also vulnerable. I'm a developer using Docker for two different purposes: Images used for ...
Jeroen's user avatar
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Which attacks are known that exploit the vulnerability known as Spectre?

As reported yesterday the Linux and Windows kernels will receive a security update pretty soon to close vulnerabilities that concern 'kernel memory leaking'. What exactly the design flaw is, that was ...
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12 votes
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What are the risks of not patching a workstation OS for Meltdown?

Assume the following: macOS (but not sure that matters that much) workstation, mostly gets new executables from the app store or open source repos through macports homebrew fair bit of loading JS, ...
Italian Philosophers 4 Monica's user avatar
5 votes
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Do I need to patch Linux for Meltdown/Spectre if the hypervisor has been patched, and I trust the guest?

If I'm running a VM on Amazon EC2 or Microsoft Azure, and they've patched the underlying hypervisor, do I need to upgrade my Linux kernel to protect against Meltdown or Spectre? Assume that I'm not ...
Roger Lipscombe's user avatar
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Why were Meltdown and Spectre disclosed at the same time?

Both the Meltdown and Spectre vulnerabilities were publicly disclosed on January 3, 2018. (6 days ahead of the originally planned January 9). Since their public reveal, there has been some confusion ...
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5 votes
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Reducing resolution of timers as mitigation against Meltdown and Spectre

I have read that Firefox' current mitigation against Meltdown and Spectre (from 57.x) consists of the following: The resolution of will be reduced to 20µs. The ...
Drux's user avatar
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Do the Spectre and Meltdown CPU bugs affect AMD in addition to Intel?

If a server or or PC is running AMD CPUs, will those be affected by the Spectre and/or Meltdown bugs currently effecting Intel chips? Why or why not? What makes it affect one and not the other? How ...
TestinginProd's user avatar
2 votes
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Does enabling SharedArrayBuffers via service worker headers create Spectre vulnerability?

In browsers, use of SharedArrayBuffer is restricted to sites with the following HTTP headers because otherwise it exposes vulnerabilities to Spectre and Meltdown. Cross-Origin-Embedder-Policy: require-...
ultraGentle's user avatar