# Spectre and Meltdown in Poutas

DevFeed: [Spectre and Meltdown in Poutas](<https://devfeed.tech/articles/spectre-and-meltdown-in-poutas-19759.md>)

Original publisher: [Read original article](<https://cloud.blog.csc.fi/2018/01/spectre-and-meltdown-in-poutas.html>)

Author: Kalle Happonen (noreply@blogger.com)

Published: 2018-01-09T13:36:00Z

Content type: article

Language: en

Sources: [CSC - IT Center For Science - Cloud Team](<https://devfeed.tech/sources/csc-it-center-for-science-cloud-team.md>)

Topics: [cpu](<https://devfeed.tech/topics/cpu.md>), [Vulnerabilities](<https://devfeed.tech/topics/vulnerabilities.md>), [Exploit](<https://devfeed.tech/topics/exploit.md>), [virtual machines](<https://devfeed.tech/topics/virtual-machines.md>), [Linux](<https://devfeed.tech/topics/linux.md>), [Ubuntu](<https://devfeed.tech/topics/ubuntu.md>), [x86](<https://devfeed.tech/topics/x86.md>), [passwords](<https://devfeed.tech/topics/passwords.md>)

Tags: [apt](<https://devfeed.tech/tags/apt.md>), [cpu](<https://devfeed.tech/tags/cpu.md>), [exploit](<https://devfeed.tech/tags/exploit.md>), [installation](<https://devfeed.tech/tags/installation.md>), [linux](<https://devfeed.tech/tags/linux.md>), [packages](<https://devfeed.tech/tags/packages.md>), [passwords](<https://devfeed.tech/tags/passwords.md>), [ubuntu](<https://devfeed.tech/tags/ubuntu.md>), [update](<https://devfeed.tech/tags/update.md>), [virtual-machines](<https://devfeed.tech/tags/virtual-machines.md>), [vulnerabilities](<https://devfeed.tech/tags/vulnerabilities.md>), [x86](<https://devfeed.tech/tags/x86.md>)

## AI overview

This article explains the Spectre and Meltdown CPU vulnerabilities and their impact on cloud providers and customers. It recommends updating kernels and rebooting virtual machines, with specific instructions for Ubuntu and CentOS. Meltdown requires immediate mitigation, while Spectre is harder to fully mitigate.

## Source excerpt

Three serious CPU vulnerabilities were revealed last week, and they require immediate action. Both we as providers and you as customers are affected. Meltdown should be mitigated against immediately. Update the kernels on your virtual machines and reboot your virtual machines. 2018-01-10 13:45: Ubuntu has released new kernel patches, which should work. We recommend upgrading the kernels on Ubuntu and rebooting the virtual machines. Why is it relevant to me? There are a lot of resources to learn about the vulnerabilities online, the official resource linked above is a good place to start. In short, the vulnerability lets other users on the same machine read memory they should not. Meltdown (variant 3) is the easiest to patch against and you need to patch it on the virtual machine. Spectre (variant 1) has a more limited impact, and the kernel patch mitigates it. Spectre (variant 2) is harder to exploit, but it needs patches from our side. At worst these vulnerabilities can cause leaks of secret keys, passwords and other private information to third parties. Please note that Spectre is hard to completely mitigate against. We expect more variants to be released in time. We are following the situation. What should I do as a customer? First of all, install the latest kernel and reboot your virtual machines. CentOS instructions Installation (note: since autoupdates are enabled, this you might already have packages installed and just need a reboot): sudo -i yum install kernel reboot Verification: dmesg |grep "x86/pti" If you see a line like [ 0.000000] x86/pti: Unmapping kernel while in userspace you have a kernel with the patches. Ubuntu instructions Installation (note: since autoupdates are enabled, this you might already have packages installed and just need a reboot): sudo -i apt update apt install linux-image-generic reboot Verification: dmesg |grep isolation If you see a line like [ 0.000000] Kernel/User page tables isolation: enabled you have a kernel with the patche