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linux, linux-aws, linux-kvm, linux-raspi2, linux-snapdragon vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 16.04 LTS

Summary

Several security issues were fixed in the Linux kernel.

Software Description

  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-kvm - Linux kernel for cloud environments
  • linux-raspi2 - Linux kernel for Raspberry Pi 2
  • linux-snapdragon - Linux kernel for Snapdragon processors

Details

It was discovered that memory present in the L1 data cache of an Intel CPU core may be exposed to a malicious process that is executing on the CPU core. This vulnerability is also known as L1 Terminal Fault (L1TF). A local attacker in a guest virtual machine could use this to expose sensitive information (memory from other guests or the host OS). (CVE-2018-3646)

It was discovered that memory present in the L1 data cache of an Intel CPU core may be exposed to a malicious process that is executing on the CPU core. This vulnerability is also known as L1 Terminal Fault (L1TF). A local attacker could use this to expose sensitive information (memory from the kernel or other processes). (CVE-2018-3620)

Juha-Matti Tilli discovered that the TCP implementation in the Linux kernel performed algorithmically expensive operations in some situations when handling incoming packets. A remote attacker could use this to cause a denial of service. (CVE-2018-5390)

Juha-Matti Tilli discovered that the IP implementation in the Linux kernel performed algorithmically expensive operations in some situations when handling incoming packet fragments. A remote attacker could use this to cause a denial of service. (CVE-2018-5391)

Update instructions

The problem can be corrected by updating your system to the following package versions:

Ubuntu 16.04 LTS
linux-image-4.4.0-1031-kvm - 4.4.0-1031.37
linux-image-4.4.0-1065-aws - 4.4.0-1065.75
linux-image-4.4.0-1094-raspi2 - 4.4.0-1094.102
linux-image-4.4.0-1098-snapdragon - 4.4.0-1098.103
linux-image-4.4.0-133-generic - 4.4.0-133.159
linux-image-4.4.0-133-generic-lpae - 4.4.0-133.159
linux-image-4.4.0-133-lowlatency - 4.4.0-133.159
linux-image-4.4.0-133-powerpc-e500mc - 4.4.0-133.159
linux-image-4.4.0-133-powerpc-smp - 4.4.0-133.159
linux-image-4.4.0-133-powerpc64-emb - 4.4.0-133.159
linux-image-4.4.0-133-powerpc64-smp - 4.4.0-133.159
linux-image-aws - 4.4.0.1065.67
linux-image-generic - 4.4.0.133.139
linux-image-generic-lpae - 4.4.0.133.139
linux-image-kvm - 4.4.0.1031.30
linux-image-lowlatency - 4.4.0.133.139
linux-image-powerpc-e500mc - 4.4.0.133.139
linux-image-powerpc-smp - 4.4.0.133.139
linux-image-powerpc64-emb - 4.4.0.133.139
linux-image-powerpc64-smp - 4.4.0.133.139
linux-image-raspi2 - 4.4.0.1094.94
linux-image-snapdragon - 4.4.0.1098.90

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

Please note that the recommended mitigation for CVE-2018-3646 involves updating processor microcode in addition to updating the kernel; however, the kernel includes a fallback for processors that have not received microcode updates.

After a standard system update you need to reboot your computer to make all the necessary changes.

ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well.

References


Read full article on Ubuntu Security