ESB-2017.2981 - [Ubuntu] linux-azure: Root compromise - Existing account 2017-11-22

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2017.2981
                    Linux kernel (Azure) vulnerability
                             22 November 2017

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           linux-azure
Publisher:         Ubuntu
Operating System:  Ubuntu
Impact/Access:     Root Compromise   -- Existing Account
                   Denial of Service -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2017-12188  

Reference:         ESB-2017.2978

Original Bulletin: 
   http://www.ubuntu.com/usn/usn-3488-1

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Ubuntu Security Notice USN-3488-1
November 21, 2017

linux-azure vulnerability
==========================================================================

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

- - Ubuntu 16.04 LTS

Summary:

The system could be made to crash or run programs as an administrator.

Software Description:
- - linux-azure: Linux kernel for Microsoft Azure Cloud systems

Details:

It was discovered that the KVM subsystem in the Linux kernel did not
properly keep track of nested levels in guest page tables. A local attacker
in a guest VM could use this to cause a denial of service (host OS crash)
or possibly execute arbitrary code in the host OS.

Update instructions:

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

Ubuntu 16.04 LTS:
  linux-image-4.11.0-1015-azure   4.11.0-1015.15
  linux-image-azure               4.11.0.1015.15

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://www.ubuntu.com/usn/usn-3488-1
  CVE-2017-12188

Package Information:
  https://launchpad.net/ubuntu/+source/linux-azure/4.11.0-1015.15

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