Questions tagged [spectre]

A side-channel vulnerability affecting modern microprocessors that perform branch prediction like Intel, AMD, ARM, Sparc and PowerPC allowing user processes to read memory belonging to other processes. Affects Linux, OS X, and Windows. Published in January 2018.

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Sacrificing 30% of my CPU performance (by disabling Hyper-Threading) to fully mitigate CPU vulnerabilities, necessary?

I used the spectre-meltdown-checker, version 0.42, without any option resulting in all-green results. But, in a help page, I found the --paranoid switch, which resulted in about a half of later CVEs ...
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are small SOC chips also affected by Meltdown and Spectre?

How can I find out, if given CPU is affected by the Meltdown and Spectre bugs ? My CPU is relatively older, and it is a SOC chip: AMD GX-412TC SOC I was not able to find, whether these chips also ...
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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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Application level protection against Meltdown, Spectre, Foreshadow, Fallout. Zombieload

Is it possible to develop an application in such a way that its data in memory cant be stolen by recent attacks such as Meltdown, Spectre, Foreshadow, Fallout. Zombieload? All mitigations focus on ...
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What kind of attacks can hardware level memory encryption protect from?

Both AMD and Intel have introduced memory encryption at the hardware level. AMD calls this Secure Memory Encryption (SME), with the Intel version being Total Memory Encryption (TME). What kind of ...
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Mitigation of Spectre and Meltdown affecting host OS from guest OS (Virtualbox)

I don't know all the details of Spectre and Meltdown, but the way I understand it is that they allow reading from memory, not writing to it. Also, I read that at least Spectre can get out of the ...
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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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How would one compare Cache Allocating Technology against MIT's Dynamically Allocated Way Guard for prevention of the Spectre side-channel Attack?

Upon research, I'm finding it difficult to identify a way to compare each solution. Is it correct in saying both solutions are software based? Therefore, could I compare overall PC perfomance with ...
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Do I need microcode update if I update Kernel?

There is a CPU vulnerability Microarchitectural Fill Buffer Data Sampling. I use a Linux OS and I think to fix Microarchitectural Fill Buffer Data Sampling you need to update intel microcode or ...
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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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Software mitigation for variant 3a (rogue system register read) and variant 4 (speculative store bypass)

AFAIK, all mitigable meltdown / spectre variants have software mitigation except for variant 3a and 4. Why is this the case? For variant 4, a straightforward software mitigation is to place lfence ...
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Compiling with GCC retpoline flags

As of version 8 (later backported to 7.3), GCC has added retpoline support [0]. While I understand that it is intended[citation needed] for use in kernel patching for Spectre (ie: [1][2]), that does ...
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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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What is NetSpectre?

A new attack was revealed in a document titled NetSpectre: Read Arbitrary Memory over Network (PDF warning). I've seen a few non-technical writeups about the fact that it's a pretty slow attack: ...
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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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Is Meltdown/Spectre mitigation necessary in virtual machine as well as in hypervisor? [duplicate]

I am running virtual machines in kvm/qemu hypervisor. The hypervisor has Meltdown/Spectre mitigation enabled in kernel. Is it necessary that virtual machines have the Meltdown/Spectre mitigation ...
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Meltdown checker says AWS and Rackspace is vulnerable - Why?

Today I was curious how my vmware environment stacked up against Spectre and Meltdown. So I ran spectre-meltdown-checker. It came back clean with 7 of 8 variants OK (the failed one is apparently ...
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Can someone explain in layman terms how Spectre and Meltdown expose protected data

I'm working on a document about them and I think I understand it general what happens -> by exploiting the CPUs memory caching and speculative execution but I'm a little lost of how protected data is ...
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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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Do any speculative executation attacks affect ARMv7 CPUs?

Do we know if there are speculative execution attacks that affect ARMv7 CPUs at this time? Are there any theoretical risks that need further investigation?
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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 ...
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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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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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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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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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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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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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Why is there no spectre local root exploit in circulation?

I heard that Spectre could be used to reveal arbitrary information from RAM and I imagine it should ultimately be possible to automate getting root this way. At the same time, quite a couple of months ...
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What is the attack vector for CVE-2018-3639 Speculative Store Bypass?

We use Web Application deployed on a CentOS server. Can the attack will be performed via a browser? Or the attacker need a physical access to the CentOS server? I cannot understand the attack vector ...
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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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Does Speculative Store Bypass Attack Require Assembly/Source Code Knowledge?

ok, so the gist of speculative store bypass attack to my understanding is that, cpu chooses the most frequent code path, bypass the if/else test and just assumes that it's true/false and then execute ...
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What Spectre V2 patches fixes which vulnerabilties on Linux?

Let's assume I have a computer with a pre-Skylake Intel processor that doesn't have microcode mitigating the Spectre V2 attack. Then to my understanding, if the kernel and all user-space applications ...
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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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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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AMD K8 processors may not be vulnerable to Spectre?

I've been chewing on this for a week or so. Thought I'd ask if it could be validated. My thoughts are based on reading the Spectre whitepaper and research on the AMD K8 microarchitecture, and haven't ...
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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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what fails in speculative execution that allows the read of memory out of bounds in Spectre vulnerability vs. normal CPU behaviour?

Following google's Project zero blog entry for Spectre/Meltdown, there's this piece of code that exemplifies the attack: struct array { unsigned long length; unsigned char data[]; }; struct ...
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Software mitigation for Spectre v2

I run Debian as my OS and Guix as my package manager. I also run (approximately) latest kernel built using Guix. According to spectre-meltdown-checker, my kernel has mitigation for v1, v2 and v3. ...
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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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Just how bad is Spectre?

Reading the whitepaper, it sounds like doom and gloom. The main webpage states “Spectre is harder to exploit than Meltdown, but it is also harder to mitigate. However, it is possible to prevent ...
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Why does my unpatched system *appear* to not be vulnerable to Spectre?

Since the corresponding research papers offer quite explicit descriptions publicly, I suppose that publishing my code below is not considered as encouraging or endorsing exploits. Nevertheless, I am ...
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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-...
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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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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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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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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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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 ...
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Spectre on AMD K7 generation : exploitable, in the real world?

Considering AMD K7-family (Ahtlon XP...) 32-bit only processors, have there been any published exploits (viz "Spectre" type attacks) or indications that such would be even remotely possible in ...
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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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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 ...