USN-3511-1: Linux kernel (Azure) vulnerabilities

Ubuntu Security Notice USN-3511-1

7th December, 2017

linux-azure 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-azure
– Linux kernel for Microsoft Azure Cloud systems

Details

Mohamed Ghannam discovered that a use-after-free vulnerability existed in
the Netlink subsystem (XFRM) in the Linux kernel. A local attacker could
use this to cause a denial of service (system crash) or possibly execute
arbitrary code. (CVE-2017-16939)

It was discovered that the Linux kernel did not properly handle copy-on-
write of transparent huge pages. A local attacker could use this to cause a
denial of service (application crashes) or possibly gain administrative
privileges. (CVE-2017-1000405)

Update instructions

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

Ubuntu 16.04 LTS:: linux-image-azure

4.11.0.1016.16; linux-image-4.11.0-1016-azure

4.11.0-1016.16

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

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.