[USN-3255-1] LightDM vulnerability

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Ubuntu Security Notice USN-3255-1
April 04, 2017

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

- Ubuntu 16.10
- Ubuntu 16.04 LTS

Summary:

LightDM could be made to run programs as an administrator.

Software Description:
- lightdm: Display Manager

Details:

It was discovered that LightDM incorrectly handled home directory creation for
guest users. A local attacker could use this issue to gain ownership of
arbitrary directory paths and possibly gain administrative privileges.

Update instructions:

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

Ubuntu 16.10:
lightdm 1.19.5-0ubuntu1.1

Ubuntu 16.04 LTS:
lightdm 1.18.3-0ubuntu1.1

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

References:
http://www.ubuntu.com/usn/usn-3255-1
CVE-2017-7358

Package Information:
https://launchpad.net/ubuntu/+source/lightdm/1.19.5-0ubuntu1.1
https://launchpad.net/ubuntu/+source/lightdm/1.18.3-0ubuntu1.1