=========================================================================Ubuntu Security Notice USN-3784-1
October 04, 2018

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

- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS

Summary:

Use a more restrictive blacklist in several policy abstractions.

Software Description:
- apparmor: Linux security system

Details:

As a security improvement, this update adjusts the private-files abstraction to
disallow writing to thumbnailer configuration files. Additionally adjust the
private-files, private-files-strict and user-files abstractions to disallow
writes on parent directories of sensitive files.

Update instructions:

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

Ubuntu 18.04 LTS:
  apparmor                        2.12-4ubuntu5.1

Ubuntu 16.04 LTS:
  apparmor                        2.10.95-0ubuntu2.10

Ubuntu 14.04 LTS:
  apparmor                        2.10.95-0ubuntu2.6~14.04.4

In general, a standard system update will make all the necessary changes.

References:
  
  https://bugs.launchpad.net/ubuntu/+source/evince/+bug/1788929, https://bugs.launchpad.net/ubuntu/+source/apparmor/+bug/1794848

Package Information:
  https://launchpad.net/ubuntu/+source/apparmor/2.12-4ubuntu5.1
  https://launchpad.net/ubuntu/+source/apparmor/2.10.95-0ubuntu2.10
  https://launchpad.net/ubuntu/+source/apparmor/2.10.95-0ubuntu2.6~14.04.4