Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
===========================================================================
AUSCERT External Security Bulletin Redistribution
ESB-2017.1212
LightDM vulnerability
12 May 2017
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: lightdm
Publisher: Ubuntu
Operating System: Ubuntu
Linux variants
Impact/Access: Unauthorised Access -- Console/Physical
Resolution: Patch/Upgrade
CVE Names: CVE-2017-8900
Original Bulletin:
http://www.ubuntu.com/usn/usn-3285-1
Comment: This advisory references vulnerabilities in products which run on
platforms other than Ubuntu. It is recommended that administrators
running lightdm check for an updated version of the software for
their operating system.
- --------------------------BEGIN INCLUDED TEXT--------------------
==========================================================================
Ubuntu Security Notice USN-3285-1
May 12, 2017
lightdm vulnerability
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- - Ubuntu 17.04
- - Ubuntu 16.10
Summary:
LightDM could allow unintended access to files.
Software Description:
- - lightdm: Display Manager
Details:
Tyler Hicks discovered that LightDM did not confine the user session for guest
users. An attacker with physical access could use this issue to access files
and other resources that they should not be able to access. In the default
installation, this includes files in the home directories of other users on the
system. This update fixes the issue by disabling the guest session. It may be
re-enabled in a future update. Please see the bug referenced below for
instructions on how to manually re-enable the guest session.
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 17.04:
lightdm 1.22.0-0ubuntu2.1
Ubuntu 16.10:
lightdm 1.19.5-0ubuntu1.2
After a standard system update you need to reboot your computer to make
all the necessary changes.
References:
http://www.ubuntu.com/usn/usn-3285-1
CVE-2017-8900, https://launchpad.net/bugs/1663157
Package Information:
https://launchpad.net/ubuntu/+source/lightdm/1.22.0-0ubuntu2.1
https://launchpad.net/ubuntu/+source/lightdm/1.19.5-0ubuntu1.2
- --------------------------END INCLUDED TEXT--------------------
You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.
NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members. As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.
NOTE: This is only the original release of the security bulletin. It may
not be updated when updates to the original are made. If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.
Contact information for the authors of the original document is included
in the Security Bulletin above. If you have any questions or need further
information, please contact them directly.
Previous advisories and external security bulletins can be retrieved from:
http://www.auscert.org.au/render.html?cid=1980
===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072
Internet Email: auscert@auscert.org.au
Facsimile: (07) 3365 7031
Telephone: (07) 3365 4417 (International: +61 7 3365 4417)
AusCERT personnel answer during Queensland business hours
which are GMT+10:00 (AEST).
On call after hours for member emergencies only.
===========================================================================
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967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=DJol
-----END PGP SIGNATURE-----