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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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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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1answer
97 views

Privacy implications of Intel CPU backdoors [closed]

I didn't follow all the episodes about backdoors in Intel CPUs What can intelligence or law enforcement agencies potentially do on a computer equipped with a vulnerable Intel CPU (connected to the ...
3
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1answer
120 views

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 ...
3
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1answer
133 views

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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1answer
83 views

Do Meltdown and Spectre affect other Intel products such as SSDs?

I've found a good deal on an Intel SSD but I don't want to worry about the security hole or the loss of performance from patching it.
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2answers
81 views

Extracting passwords from recycled machine using Spectre and Meltdown

With Spectre and Meltdown, hackers can extract your password from the CPU cache. If I give someone my computer without the hard drive, can he extract my passwords through the CPU?
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0answers
101 views

Nessus ADV180002: Microsoft SQL Server January 2018 Security Update (Meltdown) (Spectre)

I have a MS Server 2012 r2 running ArcServe 17.5, which uses MSSQL Server Express 2014. When Nessus runs a scan of this system, I am getting the plugin 105613 - ADV180002: Microsoft SQL Server January ...
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2answers
144 views

Should I wait until Spectre and Meltdown is fixed in hardware? [duplicate]

I have a Laptop that needs replacing due to age. I will be using this laptop for desktop use, including Office Apps, Development, Running VMs & Web Browsing. I will be using separation using ...
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0answers
18 views

Patch meltdown/Spectre vulnerabilities [duplicate]

Newbie question: Our inventory has Redhat VMs that need to patched against Meltdown and Spectre vulnerabilities. I need to know that to patch against meltdown/spectre. Do i need to patch only the ...
4
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1answer
221 views

Meltdown and Spectre regarding Firewalls and Sandboxing [duplicate]

I don't deeply understand Meltdown and Spectre -- all I know is that they are basically keylogging-like vulnerabilities within the CPU, which bypass any application layer stuff; correct me if I'm ...
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0answers
142 views

Proof of concept Meltdown/Spectre for ARM cores

I am looking for a test program that can exploit Meltdown/Spectre on ARM cores. Could see that there are test program for x86_64 architecture: https://github.com/IAIK/meltdown Is there similar test ...
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2answers
156 views

What is the significance of Spectre and Meltdown?

Reading up on Spectre and Meltdown attacks again, I don't get why they were hyped so much. These are cache attacks that take advantage of the instruction pipeline processing implementation in ...
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2answers
56 views

How bits/bytes are handled after performing Meltdown? [closed]

I understand how it works but for example after reading 4 bytes, how do it undertand if it was originally an integer or 4 different characters? Both of them could give a meaningfull result.
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3answers
14k views

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 ...
2
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1answer
267 views

how did the meltdown attack break KASLR in 128 steps for a target machine with 8GB RAM with 40bit randomization on a 64bit machine?

In the meltdown official paper released the authors broke the KASLR with 128 steps at worse. Unable to understand how did they come down to that number Paper for reference
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2answers
128 views

What to do against Spectre-1, Sprectre-2 and Meltdown on Linux and Windows in 01/2018? [duplicate]

How to handle Spectre-1, Spectre-2 and Meltdown for now, in 01/2018? It can almost never be wrong to do the following Stay up to date with your browser and OS e.g. Linux kernel update Update anti-...
3
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1answer
376 views

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 ...
4
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2answers
274 views

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 ...
2
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0answers
80 views

Meltdown - Reading processes info from leaked memory [closed]

Found this video: https://www.youtube.com/watch?v=De4rBaAdKNA In the video Meltdown is used to read process memory based by PID/name. How it is done? The program looks for task_struct in leaked ...
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2answers
271 views

Spectre, Meltdown to read SSH keys

I've got a VPS running on Ubuntu, accessed through SSH, passwordless and with a public key. Can Spectre and Meltdown be used to compromise it in order to get access remotely eg by reading the private ...
7
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3answers
197 views

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 ...
0
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1answer
246 views

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 ...
1
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1answer
150 views

how do CPU cache side-channel attack fit into the background of Meltdown vulnerability? [duplicate]

NOTE:I know there are similar questions out there, namely this one, but that answer is just an extraction from original paper, which didn't clarify the attack. Additionally I can see from answers ...
53
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3answers
15k views

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 ...
35
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6answers
10k views

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 ...
2
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1answer
173 views

Spectre: Problem with Understanding POC - Reading data from cache

I understand the vulnerability (Spectre) and, in theory, what the PoC does. But I do not understand the part of the PoC, when it reads or identifys the data from the cache, between the lines 86 - 108. ...
14
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1answer
716 views

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 ...
1
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1answer
123 views

Meltdown & UEFI

I've been trying to understand the risk of an unprotected BIOS being the victim of an UEFI attack using Meltdown and what the risks are compared to the bug being unpatched in the OS. What is required ...
3
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1answer
206 views

Meltdown - PoC - Reading physical address with KASLR disabled does not work

Working with this PoC https://github.com/IAIK/meltdown Running it: # ./secret [+] Secret: Sample text [+] Virtual address of secret: 0x4af528 [+] Physical address of secret: 0x172bc3528 [+] Exit ...
2
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2answers
176 views

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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1answer
106 views

Are PCs really vulnerable to Spectre type attacks due to virtual user space addressing? [duplicate]

Are Windows OS user programs vulnerable to Spectre and the other recent Intel flaws? Wouldn't the virtual memory assignment in Windows prevent such attacks, or their usefulness? Sorry if I miss ...
4
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2answers
196 views

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 ...
13
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1answer
1k views

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 ...
4
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1answer
215 views

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 ...
8
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1answer
898 views

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 ...
5
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1answer
417 views

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 ...
1
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1answer
248 views

Meltdown - Reading Process Memory Data

Tried this PoC: https://github.com/mniip/spectre-meltdown-poc Which works for the sys_call_table. I was able to read the syscall sys_read address. Wanted to test it with a sample program to read ...
4
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2answers
386 views

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 ...
4
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2answers
286 views

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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1answer
286 views

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 ...
3
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1answer
353 views

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 ...
2
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1answer
91 views

Meltdown and Spectre vs. dcache timing and dcache leak issues

I've heard an expert (or "expert") laugh the current focus on Meltdown and Spectre off by arguing that dcache timing and dcache leak issues have been known and around for years (so nothing new there .....
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1answer
243 views

How can a userspace linux process refer to a kernel address?

I would like help understanding a particular aspect of meltdown. My understanding is that the meltdown bug can be used for a userspace linux process to access kernel memory (indirectly, through a ...
12
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2answers
336 views

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 ...
54
votes
4answers
14k views

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?
2
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1answer
1k views

Could Meltdown/Spectre be exploited from C#/.Net (or other managed languages or the Midori OS)?

First off yes the correct answer is patch your OS/system. That aside: Does the memory managed features of a language like C# prevent it from being used to exploit the Meltdown security bug? What ...
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1answer
176 views

Can one sidestep Meltdown/Spectre vulnerabilities by not installing new software on a server?

Is it possible to not install new programs on a server and sidestep any Meltdown/Spectre vulnerabilities because it is only a newly identified issue. I have an SLES server that runs a fixed database ...
2
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1answer
266 views

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 ...
8
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3answers
769 views

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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0answers
84 views

Why is spectre and meltdown affecting all cpu architectures? [duplicate]

My question is regarding the recent issue of meltdown and spectre that has affected "all" processors. Initially I though it was just x86_64 architecture based processors. So when they said it affects ...