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USN-3740-1: Linux kernel vulnerabilities

14 August 2018

Several security issues were fixed in the Linux kernel.

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Releases

Packages

  • linux - Linux kernel
  • linux-aws - Linux kernel for Amazon Web Services (AWS) systems
  • linux-azure - Linux kernel for Microsoft Azure Cloud systems
  • linux-gcp - Linux kernel for Google Cloud Platform (GCP) systems
  • linux-kvm - Linux kernel for cloud environments
  • linux-oem - Linux kernel for OEM processors
  • linux-raspi2 - Linux kernel for Raspberry Pi 2

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 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)

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.

Learn more about Ubuntu Pro

Update instructions

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

Ubuntu 18.04

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.

Related notices

  • USN-3742-1: linux-image-3.13.0-155-lowlatency, linux-image-3.13.0-155-powerpc-e500, linux-image-3.13.0-155-powerpc-smp, linux-image-3.13.0-155-generic-lpae, linux-image-extra-3.13.0-155-generic, linux-image-3.13.0-155-powerpc-e500mc, linux-image-3.13.0-155-generic, linux-image-3.13.0-155-powerpc64-smp, linux, linux-image-3.13.0-155-powerpc64-emb
  • USN-3742-2: linux-image-generic-lts-trusty, linux-image-3.13.0-155-generic-lpae, linux-lts-trusty, linux-image-3.13.0-155-generic, linux-image-generic-lpae-lts-trusty
  • USN-3823-1: linux-image-3.2.0-137-powerpc-smp, linux-image-virtual, linux-image-3.2.0-137-powerpc64-smp, linux-image-3.2.0-137-generic-pae, linux-image-3.2.0-137-highbank, linux-image-3.2.0-137-generic, linux-image-3.2.0-137-virtual, linux-image-generic-pae, linux-image-highbank, linux-image-powerpc-smp, linux-image-omap, linux-image-3.2.0-137-omap, linux-image-powerpc, linux-image-generic, linux-image-powerpc64-smp, linux
  • USN-3741-2: linux-image-4.4.0-133-lowlatency, linux-image-4.4.0-133-powerpc-smp, linux-aws, linux-image-4.4.0-133-powerpc64-emb, linux-image-4.4.0-133-generic, linux-image-extra-4.4.0-133-generic, linux-image-4.4.0-133-powerpc-e500mc, linux-image-4.4.0-133-powerpc64-smp, linux-lts-xenial, linux-image-4.4.0-133-generic-lpae, linux-image-4.4.0-1027-aws
  • USN-3741-1: linux-image-4.4.0-1098-snapdragon, linux-image-4.4.0-133-lowlatency, linux-image-4.4.0-133-powerpc-smp, linux-aws, linux-raspi2, linux-image-4.4.0-133-powerpc64-emb, linux-image-4.4.0-133-generic, linux-snapdragon, linux-image-extra-4.4.0-133-generic, linux-image-4.4.0-1065-aws, linux-image-4.4.0-133-powerpc-e500mc, linux-image-4.4.0-133-powerpc64-smp, linux-image-4.4.0-133-generic-lpae, linux-kvm, linux-image-4.4.0-1031-kvm, linux-image-4.4.0-1094-raspi2, linux
  • USN-3740-2: linux-image-4.15.0-1017-gcp, linux-image-4.15.0-32-lowlatency, linux-image-unsigned-4.15.0-1021-azure, linux-gcp, linux-image-unsigned-4.15.0-32-generic, linux-image-unsigned-4.15.0-32-lowlatency, linux-image-4.15.0-32-generic-lpae, linux-azure, linux-image-4.15.0-32-generic, linux-hwe
  • USN-3756-1: intel-microcode