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 ...
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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 ...
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Spectre/meltdown on a GPU
Are GPUs vulnerable to spectre/meltdown attacks, since they have most of what makes CPUs attackable? Is there any information in the VRAM, that would cause trouble if it was stolen?
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Is it true that meltdown and spectre were intended as debug tools?
I heard from a guy that's involved in low-level (assembler, C for drivers and OSes) programming, that meltdown and spectre weren't actually vulnerabilities discovered only so recently, but they were ...
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How to mitigate Meltdown in Docker images?
On https://meltdownattack.com/ 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 ...
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Are new Intel CPUs vulnerable to Meltdown/Spectre?
Has Intel released any information about new processors?
According to their advisory a number of processors are susceptible, but it says nothing about when new processors will be fixed. Also Meltdown ...
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On Windows boxes, is patching for Spectre and Meltdown necessary?
From what I've read, Spectre and Meltdown each require rogue code to be running on a Windows box in order for attacks to take place. The thing is, once a box has rogue code running, it's already ...
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How do I check if KPTI is enabled on linux?
The Meltdown attack FAQ says that KPTI is the fix for linux. How do I check if KPTI is running/enabled?
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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 ...
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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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Are new AMD processors more secure than Intel ones?
Since the discovery of Meltdown and Spectre, CPU security has been compromised and trust to the main manufacturers reduced, particularly Intel. 8 months later I wonder, what CPUs are more secure at ...
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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 ...
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Is anyone seeing a performance decrease after applying recent kernel patch fixing Meltdown and Spectre? [closed]
Our company has a lot of CPU intensive operations on our servers, so the performance decrease is a concern for the organization.
We did the benchmarks, and it seems that performance is almost not ...
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Was Meltdown/Spectre discovered in 1991 or 1995?
Wikipedia mentions this paper without going into details: The Intel 80x86 Processor Architecture: Pitfalls for Secure Systems:
As mentioned in the preceding scenario, caches
present potential for ...
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Are Meltdown and Spectre only exploitable with compiled code?
Is a system vulnerable where the only untrusted code is interpreted, JIT'd, or executed in a VM as bytecode?
Does it depend on the language? Compiler?
Or, do attacks depend on the attacker loading ...
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How does Meltdown/Spectre impact Intel SGX?
I've been reading about Meltdown and Spectre today, and I'm wondering if they impact Intel SGX enclaves.
Now, my understanding of Meltdown is somewhat hazy, but AFAICT it does not impact secure ...
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Why are CPUs designed in a way so the "meltdown" exploit works? [duplicate]
I'm trying to wrap my head around "meltdown", but to first understand it, I've been trying to understand memory accesses.
From what I understand, the CPU attempts to look up the virtual address in ...
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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, ...
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Does recent Intel hardware mitigate Meltdown at the hardware level?
Recently a security researcher made the following claim via Twitter (emphasis added):
If you're running Windows, I'm about to publish a tool that checks if you have the "Variant 3: rogue data cache ...
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How can CPU designers prevent information leaks from speculated execution?
We know about short-term measures to mitigate the Meltdown and Spectre vulnerabilities in certain microprocessors where speculative execution has measurable effects on cache timings (mainly patches to ...
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Why is accessing kernel memory a security risk?
A lot of the news regarding the Meltdown vulnerability is emphasizing that it allows programs to read memory that should be off limits to the user. While I understand that this should not happen, few ...
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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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Mitigating Meltdown by checking the faulting address in every page fault?
Short question
Would checking if the faulting address for every page fault points to kernel memory reliably detect an attempted Meltdown exploit, on systems that lack Intel TSX (and thus cannot ...
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Can Javascript engines that run on the JVM be used to implement the Spectre exploit?
I see that Chrome and Mozilla have added mitigations into their javascript engines for the Spectre vulnerabilities (CVE-2017-5753 & CVE-2017-5715). However I cant find anything regarding ...
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Spectre and Meltdown being used in large scale attack on unpatched systems [closed]
Do we have to be worried about Spectre and Meltdown being used for a large scale attack like Wannacry? Even though the patches coming out are being deployed to a most recent systems, there will ...
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How risky would it be to run a Linux kernel without Spectre and Meltdown patches on a regular desktop system?
What would happen if we adopted: https://make-linux-fast-again.com/
Assume the system is used for development and general browsing.
Are there any cases of these vulnerabilities being exploited in ...
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Spectre/Meltdown - Does memory deallocation erase the actual RAM contents?
The other day I've been thinking about Spectre and Meltdown and the ability of one process to access the memory of another.
On my Linux system currently I have all JavaScript disabled to eliminate ...
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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 ...
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What was state of the art knowledge on security of speculative evaluation when it was introduced to Intel CPUs?
Many sources claim that almost all Intel x86 CPUs back to Pentium Pro are vulnerable to the Meltdown attack. Pentium Pro was introduced to the market in 1995.
What was the state of the art knowledge ...
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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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Why and where was Meltdown made public before schedule for the first time?
Originally, Meltdown and Spectre had a coordinated disclosure date of January 9, 2018. Some vendors were preparing to release fixes at that time, and were caught by surprise when the vulnaribilities ...
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Are mitigations for Spectre and Meltdown needed in the VMs for dynamic languages other than JavaScript?
Mitigations for Spectre and Meltdown are being added to the JavaScript VMs in Chrome, Firefox, IE/Edge and WebKit.
Are similar mitigations also needed in the VMs for other dynamic languages?
For ...
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Are VIA CPUs vulnerable to Spectre/Meltdown attacks?
I couldn't find any information about the recently published Spectre/Meltdown attacks affecting VIA CPUs.
Are they also affected by this vulnerabilities?
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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 ...
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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 performance.now() will be reduced to 20µs.
The ...
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Can speculative execution on intel cpu be disabled?
In the light of all the recent Intel Vulnerabilities with speculative execution, can speculative execution be fully disabled to protect from all this vulnerabilities, from BIOS or OS kernel?
Maybe ...
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A POWER7 processor on IBM i is currently vulnerable to Meltdowm or Spectre [duplicate]
All the updates on available linux systems have already been made.
But I also have an IBM i (AS400) server, I have not heard in the news. But obviously it is more lucrative for news channels to ...
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What do speculative execution patches protect me from?
There are a barrage of patches coming out, both at the application and OS levels for the recently disclosed speculative execution attacks against various vulnerabilities in CPUs from AMD, ARM, and ...
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What is the relationship between the GPZ research titles and Meltdown and Spectre?
I learned today that there were three vulnerabilities reported by Google Project Zero: bounds check bypass, branch target injection and rogue cache data load. Here is the AMD response to them: https://...
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Are Meltdown and Spectre exploitable on 32-bit Linux platforms?
All of the information I've seen thus far on Meltdown and Spectre explicitly reference 64-bit platforms. What about 32-bit (specifically RHEL/CentOS)? I would assume that's also vulnerable but can ...
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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 ...
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Will patching a higher layer protect against the spectre/meltdown vulnerability in a lower layer?
The question I am about to ask is similar to the following question:
Do I need to patch Linux for Meltdown/Spectre if the hypervisor has been patched, and I trust the guest?
However, I would like to ...
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What is the expected performance impact/loss of meltdown/spectre patches? [duplicate]
The patches related to the mitigation of meltdown and spectre attacks, have they caused significant and noticeable slow down of execution in systems they have been applied to?
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Can I disable access to JS APIs in the browser such as highres timers?
In the wake of recent news of CPU bugs like Meltdown and Spectre which rely on precise(-ish) measurments of elapsed time, I find myself in the mood for disabling things like window.performance.now() ...
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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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Are MCUs (Like arduinos) effected by Meltdown?
I am curious if Microcontrolers are effected by the vulnerabilities of Meltdown and Spectre. These devices are not specifically CPUs, and do not run Operating Systems per-say. I'm not really sure I ...
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Adobe Flash and Meltdown / Spectre
Many browsers have received updates to protect against the Meltdown and Spectre attacks. I presume these patches relate (solely) to JavaScript execution within the browser. Java in the browser is as ...
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How to fix Spectre variant 3a and variant 4?e
How I can fix CVE-2018-3640 [rogue system register read] aka 'Variant 3a' and CVE-2018-3639 [speculative store bypass] aka 'Variant 4'? My status for them is VULNERABLE. I have Intel CPU and using ...
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Are Meltdown and Spectre complementary and used together
Meltdown and Spectre have both been announced at the same time, almost always in the same sentence. Is there a connection, other than timing and the fact that they attack chips? Are they used together ...
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Is microcode physically able to mitigate Meltdown?
I am aware that there is no microcode fix for Meltdown available (it has already been answered in various questions), and that the only extant microcode patches (IBRS and IPBP) only help with one of ...
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