Synopsis

Moderate: kdenetwork security update

Type/Severity

Security Advisory: Moderate

Topic

Updated kdenetwork packages that fix three security issues are now
available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having Moderate security
impact. Common Vulnerability Scoring System (CVSS) base scores, which give
detailed severity ratings, are available for each vulnerability from the
CVE links in the References section.

Description

The kdenetwork packages contain networking applications for the K Desktop
Environment (KDE). Krfb Desktop Sharing, which is a part of the kdenetwork
package, is a server application that allows session sharing between users.
Krfb uses the LibVNCServer library.

A NULL pointer dereference flaw was found in the way LibVNCServer handled
certain ClientCutText message. A remote attacker could use this flaw to
crash the VNC server by sending a specially crafted ClientCutText message
from a VNC client. (CVE-2014-6053)

A divide-by-zero flaw was found in the way LibVNCServer handled the scaling
factor when it was set to "0". A remote attacker could use this flaw to
crash the VNC server using a malicious VNC client. (CVE-2014-6054)

Two stack-based buffer overflow flaws were found in the way LibVNCServer
handled file transfers. A remote attacker could use this flaw to crash the
VNC server using a malicious VNC client. (CVE-2014-6055)

Red Hat would like to thank oCERT for reporting these issues. oCERT
acknowledges Nicolas Ruff as the original reporter.

Note: Prior to this update, the kdenetwork packages used an embedded copy
of the LibVNCServer library. With this update, the kdenetwork packages have
been modified to use the system LibVNCServer packages. Therefore, the
update provided by RHSA-2014:1826 must be installed to fully address the
issues in krfb described above.

All kdenetwork users are advised to upgrade to these updated packages,
which contain backported patches to correct these issues. All running
instances of the krfb server must be restarted for this update to take
effect.

Solution

Before applying this update, make sure all previously released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to use the
Red Hat Network to apply this update are available at
https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.7 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.5 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 7.3 x86_64
• Red Hat Enterprise Linux Server from RHUI 7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.7 x86_64
• Red Hat Enterprise Linux Server - AUS 7.6 x86_64
• Red Hat Enterprise Linux Server - AUS 7.4 x86_64
• Red Hat Enterprise Linux Server - AUS 7.3 x86_64
• Red Hat Enterprise Linux Workstation 7 x86_64
• Red Hat Enterprise Linux Desktop 7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.7 x86_64
• Red Hat Enterprise Linux Server - TUS 7.6 x86_64
• Red Hat Enterprise Linux Server - TUS 7.3 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.7 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.6 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.4 x86_64
• Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.3 x86_64

Fixes

• BZ - RHSA-2014:1827 - CVE-2014-6053 libvncserver: server NULL pointer dereference flaw in ClientCutText message handling
• BZ - RHSA-2014:1827 - CVE-2014-6054 libvncserver: server divide-by-zero flaw in scaling factor handling
• BZ - RHSA-2014:1827 - CVE-2014-6055 libvncserver: server stacked-based buffer overflow flaws in file transfer handling

CVEs

• CVE-2014-6053
• CVE-2014-6054
• CVE-2014-6055

References