Ubuntu 16.04 LTS: USN-3776-1 Moderate: Kernel Denial Of Service Threats

ubuntu

October 1, 2018

Several security issues were fixed in the Linux kernel.

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:

Jann Horn discovered that the vmacache subsystem did not properly handle

sequence number overflows, leading to a use-after-free vulnerability. A

local attacker could use this to cause a denial of service (system crash)

or execute arbitrary code. (CVE-2018-17182)

It was discovered that the paravirtualization implementation in the Linux

kernel did not properly handle some indirect calls, reducing the

effectiveness of Spectre v2 mitigations for paravirtual guests. A local

attacker could use this to expose sensitive information. (CVE-2018-15594)

It was discovered that microprocessors utilizing speculative execution and

prediction of return addresses via Retur...

Read the Full Advisory

Topics Covered

security advisory denial of service buffer overflow Ubuntu information exposure kernel issues use-after-free

Update Instructions

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

Ubuntu 16.04 LTS:
  linux-image-4.4.0-1035-kvm      4.4.0-1035.41
  linux-image-4.4.0-1069-aws      4.4.0-1069.79
  linux-image-4.4.0-1098-raspi2   4.4.0-1098.106
  linux-image-4.4.0-1102-snapdragon  4.4.0-1102.107
  linux-image-4.4.0-137-generic   4.4.0-137.163
  linux-image-4.4.0-137-generic-lpae  4.4.0-137.163
  linux-image-4.4.0-137-lowlatency  4.4.0-137.163
  linux-image-4.4.0-137-powerpc-e500mc  4.4.0-137.163
  linux-image-4.4.0-137-powerpc-smp  4.4.0-137.163
  linux-image-4.4.0-137-powerpc64-emb  4.4.0-137.163
  linux-image-4.4.0-137-powerpc64-smp  4.4.0-137.163
  linux-image-aws                 4.4.0.1069.71
  linux-image-generic             4.4.0.137.143
  linux-image-generic-lpae        4.4.0.137.143
  linux-image-kvm                 4.4.0.1035.34
  linux-image-lowlatency          4.4.0.137.143
  linux-image-powerpc-e500mc      4.4.0.137.143
  linux-image-powerpc-smp         4.4.0.137.143
  linux-image-powerpc64-emb       4.4.0.137.143
  linux-image-powerpc64-smp       4.4.0.137.143
  linux-image-raspi2              4.4.0.1098.98
  linux-image-snapdragon          4.4.0.1102.94

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.