ESB-2017.1901 - [UNIX/Linux][RedHat] gdm and gnome-session: Unauthorised access - Console/physical 2017-08-02

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2017.1901
 Moderate: gdm and gnome-session security, bug fix, and enhancement update
                               2 August 2017

===========================================================================

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

Product:           gdm and gnome-session
Publisher:         Red Hat
Operating System:  Red Hat Enterprise Linux Server 7
                   Red Hat Enterprise Linux WS/Desktop 7
                   UNIX variants (UNIX, Linux, OSX)
Impact/Access:     Unauthorised Access -- Console/Physical
Resolution:        Patch/Upgrade
CVE Names:         CVE-2015-7496  

Original Bulletin: 
   https://access.redhat.com/errata/RHSA-2017:2128

Comment: This advisory references vulnerabilities in products which run on 
         platforms other than Red Hat. It is recommended that administrators
         running gdm and gnome-session check for an updated version of the 
         software for their operating system.

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                   Red Hat Security Advisory

Synopsis:          Moderate: gdm and gnome-session security, bug fix, and enhancement update
Advisory ID:       RHSA-2017:2128-01
Product:           Red Hat Enterprise Linux
Advisory URL:      https://access.redhat.com/errata/RHSA-2017:2128
Issue date:        2017-08-01
CVE Names:         CVE-2015-7496 
=====================================================================

1. Summary:

An update for gdm and gnome-session is now available for Red Hat Enterprise
Linux 7.

Red Hat Product Security has rated this update as having a security impact
of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which
gives a detailed severity rating, is available for each vulnerability from
the CVE link(s) in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Client (v. 7) - x86_64
Red Hat Enterprise Linux Client Optional (v. 7) - x86_64
Red Hat Enterprise Linux ComputeNode Optional (v. 7) - x86_64
Red Hat Enterprise Linux Server (v. 7) - aarch64, ppc64, ppc64le, s390x, x86_64
Red Hat Enterprise Linux Server Optional (v. 7) - aarch64, ppc64, ppc64le, s390x, x86_64
Red Hat Enterprise Linux Workstation (v. 7) - x86_64
Red Hat Enterprise Linux Workstation Optional (v. 7) - x86_64

3. Description:

The GNOME Display Manager (GDM) provides the graphical login screen shown
shortly after boot up, log out, and when user-switching.

The following packages have been upgraded to a later upstream version: gdm
(3.22.3), gnome-session (3.22.3). (BZ#1386862, BZ#1386957)

Security Fix(es):

* It was found that gdm could crash due to a signal handler dispatched to
an invalid conversation. An attacker could crash gdm by holding the escape
key when the screen is locked, possibly bypassing the locked screen.
(CVE-2015-7496)

Additional Changes:

For detailed information on changes in this release, see the Red Hat
Enterprise Linux 7.4 Release Notes linked from the References section.

4. Solution:

For details on how to apply this update, which includes the changes
described in this advisory, refer to:

https://access.redhat.com/articles/11258

GDM must be restarted for this update to take effect.

5. Bugs fixed (https://bugzilla.redhat.com/):

1273156 - GDM does not work with XDMCP indirect
1283279 - CVE-2015-7496 gdm: Crash when holding Escape in log screen
1373837 - gdm not starting because of error in config
1386862 - rebase gdm to 3.22.x
1386957 - rebase gnome-session to 3.22.x
1392970 - gnome-session-failed segfaults on hard GDM service stop
1448209 - Locked screen does not show a message to insert the smartcard when smartcard is removed
1449632 - Fuzzy translations in de, es, fr, it, ja, ko, pt_BR, ru, zh_CN, zh_TW

6. Package List:

Red Hat Enterprise Linux Client (v. 7):

Source:
gdm-3.22.3-11.el7.src.rpm
gnome-session-3.22.3-4.el7.src.rpm

x86_64:
gdm-3.22.3-11.el7.i686.rpm
gdm-3.22.3-11.el7.x86_64.rpm
gdm-debuginfo-3.22.3-11.el7.i686.rpm
gdm-debuginfo-3.22.3-11.el7.x86_64.rpm
gnome-session-3.22.3-4.el7.x86_64.rpm
gnome-session-debuginfo-3.22.3-4.el7.x86_64.rpm
gnome-session-xsession-3.22.3-4.el7.x86_64.rpm

Red Hat Enterprise Linux Client Optional (v. 7):

x86_64:
gdm-debuginfo-3.22.3-11.el7.i686.rpm
gdm-debuginfo-3.22.3-11.el7.x86_64.rpm
gdm-devel-3.22.3-11.el7.i686.rpm
gdm-devel-3.22.3-11.el7.x86_64.rpm
gnome-session-custom-session-3.22.3-4.el7.x86_64.rpm
gnome-session-debuginfo-3.22.3-4.el7.x86_64.rpm

Red Hat Enterprise Linux ComputeNode Optional (v. 7):

Source:
gdm-3.22.3-11.el7.src.rpm
gnome-session-3.22.3-4.el7.src.rpm

x86_64:
gdm-3.22.3-11.el7.i686.rpm
gdm-3.22.3-11.el7.x86_64.rpm
gdm-debuginfo-3.22.3-11.el7.i686.rpm
gdm-debuginfo-3.22.3-11.el7.x86_64.rpm
gdm-devel-3.22.3-11.el7.i686.rpm
gdm-devel-3.22.3-11.el7.x86_64.rpm
gnome-session-3.22.3-4.el7.x86_64.rpm
gnome-session-custom-session-3.22.3-4.el7.x86_64.rpm
gnome-session-debuginfo-3.22.3-4.el7.x86_64.rpm
gnome-session-xsession-3.22.3-4.el7.x86_64.rpm

Red Hat Enterprise Linux Server (v. 7):

Source:
gdm-3.22.3-11.el7.src.rpm
gnome-session-3.22.3-4.el7.src.rpm

aarch64:
gdm-3.22.3-11.el7.aarch64.rpm
gdm-debuginfo-3.22.3-11.el7.aarch64.rpm
gnome-session-3.22.3-4.el7.aarch64.rpm
gnome-session-debuginfo-3.22.3-4.el7.aarch64.rpm
gnome-session-xsession-3.22.3-4.el7.aarch64.rpm

ppc64:
gdm-3.22.3-11.el7.ppc.rpm
gdm-3.22.3-11.el7.ppc64.rpm
gdm-debuginfo-3.22.3-11.el7.ppc.rpm
gdm-debuginfo-3.22.3-11.el7.ppc64.rpm
gnome-session-3.22.3-4.el7.ppc64.rpm
gnome-session-debuginfo-3.22.3-4.el7.ppc64.rpm
gnome-session-xsession-3.22.3-4.el7.ppc64.rpm

ppc64le:
gdm-3.22.3-11.el7.ppc64le.rpm
gdm-debuginfo-3.22.3-11.el7.ppc64le.rpm
gnome-session-3.22.3-4.el7.ppc64le.rpm
gnome-session-debuginfo-3.22.3-4.el7.ppc64le.rpm
gnome-session-xsession-3.22.3-4.el7.ppc64le.rpm

s390x:
gdm-3.22.3-11.el7.s390.rpm
gdm-3.22.3-11.el7.s390x.rpm
gdm-debuginfo-3.22.3-11.el7.s390.rpm
gdm-debuginfo-3.22.3-11.el7.s390x.rpm
gnome-session-3.22.3-4.el7.s390x.rpm
gnome-session-debuginfo-3.22.3-4.el7.s390x.rpm
gnome-session-xsession-3.22.3-4.el7.s390x.rpm

x86_64:
gdm-3.22.3-11.el7.i686.rpm
gdm-3.22.3-11.el7.x86_64.rpm
gdm-debuginfo-3.22.3-11.el7.i686.rpm
gdm-debuginfo-3.22.3-11.el7.x86_64.rpm
gnome-session-3.22.3-4.el7.x86_64.rpm
gnome-session-debuginfo-3.22.3-4.el7.x86_64.rpm
gnome-session-xsession-3.22.3-4.el7.x86_64.rpm

Red Hat Enterprise Linux Server Optional (v. 7):

aarch64:
gdm-debuginfo-3.22.3-11.el7.aarch64.rpm
gdm-devel-3.22.3-11.el7.aarch64.rpm
gnome-session-custom-session-3.22.3-4.el7.aarch64.rpm
gnome-session-debuginfo-3.22.3-4.el7.aarch64.rpm

ppc64:
gdm-debuginfo-3.22.3-11.el7.ppc.rpm
gdm-debuginfo-3.22.3-11.el7.ppc64.rpm
gdm-devel-3.22.3-11.el7.ppc.rpm
gdm-devel-3.22.3-11.el7.ppc64.rpm
gnome-session-custom-session-3.22.3-4.el7.ppc64.rpm
gnome-session-debuginfo-3.22.3-4.el7.ppc64.rpm

ppc64le:
gdm-debuginfo-3.22.3-11.el7.ppc64le.rpm
gdm-devel-3.22.3-11.el7.ppc64le.rpm
gnome-session-custom-session-3.22.3-4.el7.ppc64le.rpm
gnome-session-debuginfo-3.22.3-4.el7.ppc64le.rpm

s390x:
gdm-debuginfo-3.22.3-11.el7.s390.rpm
gdm-debuginfo-3.22.3-11.el7.s390x.rpm
gdm-devel-3.22.3-11.el7.s390.rpm
gdm-devel-3.22.3-11.el7.s390x.rpm
gnome-session-custom-session-3.22.3-4.el7.s390x.rpm
gnome-session-debuginfo-3.22.3-4.el7.s390x.rpm

x86_64:
gdm-debuginfo-3.22.3-11.el7.i686.rpm
gdm-debuginfo-3.22.3-11.el7.x86_64.rpm
gdm-devel-3.22.3-11.el7.i686.rpm
gdm-devel-3.22.3-11.el7.x86_64.rpm
gnome-session-custom-session-3.22.3-4.el7.x86_64.rpm
gnome-session-debuginfo-3.22.3-4.el7.x86_64.rpm

Red Hat Enterprise Linux Workstation (v. 7):

Source:
gdm-3.22.3-11.el7.src.rpm
gnome-session-3.22.3-4.el7.src.rpm

x86_64:
gdm-3.22.3-11.el7.i686.rpm
gdm-3.22.3-11.el7.x86_64.rpm
gdm-debuginfo-3.22.3-11.el7.i686.rpm
gdm-debuginfo-3.22.3-11.el7.x86_64.rpm
gnome-session-3.22.3-4.el7.x86_64.rpm
gnome-session-debuginfo-3.22.3-4.el7.x86_64.rpm
gnome-session-xsession-3.22.3-4.el7.x86_64.rpm

Red Hat Enterprise Linux Workstation Optional (v. 7):

x86_64:
gdm-debuginfo-3.22.3-11.el7.i686.rpm
gdm-debuginfo-3.22.3-11.el7.x86_64.rpm
gdm-devel-3.22.3-11.el7.i686.rpm
gdm-devel-3.22.3-11.el7.x86_64.rpm
gnome-session-custom-session-3.22.3-4.el7.x86_64.rpm
gnome-session-debuginfo-3.22.3-4.el7.x86_64.rpm

These packages are GPG signed by Red Hat for security.  Our key and
details on how to verify the signature are available from
https://access.redhat.com/security/team/key/

7. References:

https://access.redhat.com/security/cve/CVE-2015-7496
https://access.redhat.com/security/updates/classification/#moderate
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/7.4_Release_Notes/index.html

8. Contact:

The Red Hat security contact is <secalert@redhat.com>. More contact
details at https://access.redhat.com/security/team/contact/

Copyright 2017 Red Hat, Inc.
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