==========================================================================
Ubuntu Security Notice USN-3732-2
August 06, 2018

linux-hwe, linux-azure, linux-gcp vulnerability
==========================================================================

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

- Ubuntu 16.04 LTS

Summary:

The system could be made unavailable if it received specially crafted
network traffic.

Software Description:
- linux-azure: Linux kernel for Microsoft Azure Cloud systems
- linux-gcp: Linux kernel for Google Cloud Platform (GCP) systems
- linux-hwe: Linux hardware enablement (HWE) kernel

Details:

USN-3732-1 fixed vulnerabilities in the Linux kernel for Ubuntu 18.04
LTS. This update provides the corresponding updates for the Linux
Hardware Enablement (HWE) kernel from Ubuntu 18.04 LTS for Ubuntu
16.04 LTS.

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.

Update instructions:

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

Ubuntu 16.04 LTS:
  linux-image-4.15.0-1015-gcp     4.15.0-1015.15~16.04.1
  linux-image-4.15.0-1019-azure   4.15.0-1019.19~16.04.1
  linux-image-4.15.0-30-generic   4.15.0-30.32~16.04.1
  linux-image-4.15.0-30-generic-lpae  4.15.0-30.32~16.04.1
  linux-image-4.15.0-30-lowlatency  4.15.0-30.32~16.04.1
  linux-image-azure               4.15.0.1019.25
  linux-image-gcp                 4.15.0.1015.27
  linux-image-generic-hwe-16.04   4.15.0.30.52
  linux-image-generic-lpae-hwe-16.04  4.15.0.30.52
  linux-image-gke                 4.15.0.1015.27
  linux-image-lowlatency-hwe-16.04  4.15.0.30.52

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:
  https://usn.ubuntu.com/usn/usn-3732-2
  https://usn.ubuntu.com/usn/usn-3732-1
  CVE-2018-5390

Package Information:
  https://launchpad.net/ubuntu/+source/linux-azure/4.15.0-1019.19~16.04.1
  https://launchpad.net/ubuntu/+source/linux-gcp/4.15.0-1015.15~16.04.1
  https://launchpad.net/ubuntu/+source/linux-hwe/4.15.0-30.32~16.04.1