ESB-2017.1886 - [RedHat] tigervnc and fltk: Denial of service - Remote/unauthenticated 2017-08-02

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===========================================================================
             AUSCERT External Security Bulletin Redistribution

                               ESB-2017.1886
   Moderate: tigervnc and fltk security, bug fix, and enhancement update
                               2 August 2017

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

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

Product:           tigervnc
                   fltk
Publisher:         Red Hat
Operating System:  Red Hat Enterprise Linux Server 7
                   Red Hat Enterprise Linux WS/Desktop 7
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2017-7396 CVE-2017-7395 CVE-2017-7394
                   CVE-2017-7393 CVE-2017-7392 CVE-2017-5581
                   CVE-2016-10207  

Reference:         ESB-2017.0748

Original Bulletin: 
   https://access.redhat.com/errata/RHSA-2017:2000

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=====================================================================
                   Red Hat Security Advisory

Synopsis:          Moderate: tigervnc and fltk security, bug fix, and enhancement update
Advisory ID:       RHSA-2017:2000-01
Product:           Red Hat Enterprise Linux
Advisory URL:      https://access.redhat.com/errata/RHSA-2017:2000
Issue date:        2017-08-01
CVE Names:         CVE-2016-10207 CVE-2017-5581 CVE-2017-7392 
                   CVE-2017-7393 CVE-2017-7394 CVE-2017-7395 
                   CVE-2017-7396 
=====================================================================

1. Summary:

An update for tigervnc and fltk 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) - noarch, x86_64
Red Hat Enterprise Linux Client Optional (v. 7) - noarch, x86_64
Red Hat Enterprise Linux ComputeNode (v. 7) - noarch, x86_64
Red Hat Enterprise Linux ComputeNode Optional (v. 7) - noarch, x86_64
Red Hat Enterprise Linux Server (v. 7) - aarch64, noarch, ppc64, ppc64le, s390x, x86_64
Red Hat Enterprise Linux Server Optional (v. 7) - aarch64, noarch, ppc64, ppc64le, s390x, x86_64
Red Hat Enterprise Linux Workstation (v. 7) - noarch, x86_64
Red Hat Enterprise Linux Workstation Optional (v. 7) - noarch, x86_64

3. Description:

Virtual Network Computing (VNC) is a remote display system which allows
users to view a computing desktop environment not only on the machine where
it is running, but from anywhere on the Internet and from a wide variety of
machine architectures. TigerVNC is a suite of VNC servers and clients which
allows users to connect to other desktops running a VNC server.

FLTK (pronounced "fulltick") is a cross-platform C++ GUI toolkit. It
provides modern GUI functionality without the bloat, and supports 3D
graphics via OpenGL and its built-in GLUT emulation.

The following packages have been upgraded to a later upstream version:
tigervnc (1.8.0), fltk (1.3.4). (BZ#1388620, BZ#1413598)

Security Fix(es):

* A denial of service flaw was found in the TigerVNC's Xvnc server. A
remote unauthenticated attacker could use this flaw to make Xvnc crash by
terminating the TLS handshake process early. (CVE-2016-10207)

* A double free flaw was found in the way TigerVNC handled ClientFence
messages. A remote, authenticated attacker could use this flaw to make Xvnc
crash by sending specially crafted ClientFence messages, resulting in
denial of service. (CVE-2017-7393)

* A missing input sanitization flaw was found in the way TigerVNC handled
credentials. A remote unauthenticated attacker could use this flaw to make
Xvnc crash by sending specially crafted usernames, resulting in denial of
service. (CVE-2017-7394)

* An integer overflow flaw was found in the way TigerVNC handled
ClientCutText messages. A remote, authenticated attacker could use this
flaw to make Xvnc crash by sending specially crafted ClientCutText
messages, resulting in denial of service. (CVE-2017-7395)

* A buffer overflow flaw, leading to memory corruption, was found in
TigerVNC viewer. A remote malicious VNC server could use this flaw to crash
the client vncviewer process resulting in denial of service.
(CVE-2017-5581)

* A memory leak flaw was found in the way TigerVNC handled termination of
VeNCrypt connections. A remote unauthenticated attacker could repeatedly
send connection requests to the Xvnc server, causing it to consume large
amounts of memory resources over time, and ultimately leading to a denial
of service due to memory exhaustion. (CVE-2017-7392)

* A memory leak flaw was found in the way TigerVNC handled client
connections. A remote unauthenticated attacker could repeatedly send
connection requests to the Xvnc server, causing it to consume large amounts
of memory resources over time, and ultimately leading to a denial of
service due to memory exhaustion. (CVE-2017-7396)

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

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

1343899 - Disabling vncconfig window
1358090 - shared memory leakage in vncviewer
1388620 - [REBASE] Tigervnc from 1.3 to 1.8
1393971 - [RFE] systemd unit for Xvnc (not vncserver)
1410164 - tigervnc-server fails to remove /tmp files if not gracefully shut down
1413598 - [REBASE] Update fltk to 1.3.4 for tigervnc
1415547 - Rebuilding tigervnc SRPM stops at applying Patch101
1415712 - CVE-2017-5581 tigervnc: Buffer overflow in ModifiablePixelBuffer::fillRect
1418761 - CVE-2016-10207 tigervnc: VNC server can crash when TLS handshake terminates early
1438694 - CVE-2017-7392 tigervnc: SSecurityVeNCrypt memory leak
1438697 - CVE-2017-7393 tigervnc: Double free via crafted fences
1438700 - CVE-2017-7394 tigervnc: Server crash via long usernames
1438701 - CVE-2017-7395 tigervnc: Integer overflow in SMsgReader::readClientCutText
1438703 - CVE-2017-7396 tigervnc: SecurityServer and ClientServer memory leaks

6. Package List:

Red Hat Enterprise Linux Client (v. 7):

Source:
fltk-1.3.4-1.el7.src.rpm
tigervnc-1.8.0-1.el7.src.rpm

noarch:
tigervnc-icons-1.8.0-1.el7.noarch.rpm
tigervnc-license-1.8.0-1.el7.noarch.rpm

x86_64:
fltk-1.3.4-1.el7.i686.rpm
fltk-1.3.4-1.el7.x86_64.rpm
fltk-debuginfo-1.3.4-1.el7.i686.rpm
fltk-debuginfo-1.3.4-1.el7.x86_64.rpm
tigervnc-1.8.0-1.el7.x86_64.rpm
tigervnc-debuginfo-1.8.0-1.el7.x86_64.rpm
tigervnc-server-1.8.0-1.el7.x86_64.rpm
tigervnc-server-minimal-1.8.0-1.el7.x86_64.rpm

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

noarch:
tigervnc-server-applet-1.8.0-1.el7.noarch.rpm

x86_64:
fltk-debuginfo-1.3.4-1.el7.i686.rpm
fltk-debuginfo-1.3.4-1.el7.x86_64.rpm
fltk-devel-1.3.4-1.el7.i686.rpm
fltk-devel-1.3.4-1.el7.x86_64.rpm
fltk-fluid-1.3.4-1.el7.x86_64.rpm
fltk-static-1.3.4-1.el7.i686.rpm
fltk-static-1.3.4-1.el7.x86_64.rpm
tigervnc-debuginfo-1.8.0-1.el7.x86_64.rpm
tigervnc-server-module-1.8.0-1.el7.x86_64.rpm

Red Hat Enterprise Linux ComputeNode (v. 7):

Source:
tigervnc-1.8.0-1.el7.src.rpm

noarch:
tigervnc-license-1.8.0-1.el7.noarch.rpm

x86_64:
tigervnc-debuginfo-1.8.0-1.el7.x86_64.rpm
tigervnc-server-minimal-1.8.0-1.el7.x86_64.rpm

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

Source:
fltk-1.3.4-1.el7.src.rpm

noarch:
tigervnc-icons-1.8.0-1.el7.noarch.rpm
tigervnc-server-applet-1.8.0-1.el7.noarch.rpm

x86_64:
fltk-1.3.4-1.el7.i686.rpm
fltk-1.3.4-1.el7.x86_64.rpm
fltk-debuginfo-1.3.4-1.el7.i686.rpm
fltk-debuginfo-1.3.4-1.el7.x86_64.rpm
fltk-devel-1.3.4-1.el7.i686.rpm
fltk-devel-1.3.4-1.el7.x86_64.rpm
fltk-fluid-1.3.4-1.el7.x86_64.rpm
fltk-static-1.3.4-1.el7.i686.rpm
fltk-static-1.3.4-1.el7.x86_64.rpm
tigervnc-1.8.0-1.el7.x86_64.rpm
tigervnc-debuginfo-1.8.0-1.el7.x86_64.rpm
tigervnc-server-1.8.0-1.el7.x86_64.rpm
tigervnc-server-module-1.8.0-1.el7.x86_64.rpm

Red Hat Enterprise Linux Server (v. 7):

Source:
fltk-1.3.4-1.el7.src.rpm
tigervnc-1.8.0-1.el7.src.rpm

aarch64:
fltk-1.3.4-1.el7.aarch64.rpm
fltk-debuginfo-1.3.4-1.el7.aarch64.rpm
tigervnc-1.8.0-1.el7.aarch64.rpm
tigervnc-debuginfo-1.8.0-1.el7.aarch64.rpm
tigervnc-server-1.8.0-1.el7.aarch64.rpm
tigervnc-server-minimal-1.8.0-1.el7.aarch64.rpm

noarch:
tigervnc-icons-1.8.0-1.el7.noarch.rpm
tigervnc-license-1.8.0-1.el7.noarch.rpm

ppc64:
fltk-1.3.4-1.el7.ppc.rpm
fltk-1.3.4-1.el7.ppc64.rpm
fltk-debuginfo-1.3.4-1.el7.ppc.rpm
fltk-debuginfo-1.3.4-1.el7.ppc64.rpm
tigervnc-1.8.0-1.el7.ppc64.rpm
tigervnc-debuginfo-1.8.0-1.el7.ppc64.rpm
tigervnc-server-1.8.0-1.el7.ppc64.rpm
tigervnc-server-minimal-1.8.0-1.el7.ppc64.rpm

ppc64le:
fltk-1.3.4-1.el7.ppc64le.rpm
fltk-debuginfo-1.3.4-1.el7.ppc64le.rpm
tigervnc-1.8.0-1.el7.ppc64le.rpm
tigervnc-debuginfo-1.8.0-1.el7.ppc64le.rpm
tigervnc-server-1.8.0-1.el7.ppc64le.rpm
tigervnc-server-minimal-1.8.0-1.el7.ppc64le.rpm

s390x:
fltk-1.3.4-1.el7.s390.rpm
fltk-1.3.4-1.el7.s390x.rpm
fltk-debuginfo-1.3.4-1.el7.s390.rpm
fltk-debuginfo-1.3.4-1.el7.s390x.rpm
tigervnc-1.8.0-1.el7.s390x.rpm
tigervnc-debuginfo-1.8.0-1.el7.s390x.rpm
tigervnc-server-1.8.0-1.el7.s390x.rpm
tigervnc-server-minimal-1.8.0-1.el7.s390x.rpm

x86_64:
fltk-1.3.4-1.el7.i686.rpm
fltk-1.3.4-1.el7.x86_64.rpm
fltk-debuginfo-1.3.4-1.el7.i686.rpm
fltk-debuginfo-1.3.4-1.el7.x86_64.rpm
tigervnc-1.8.0-1.el7.x86_64.rpm
tigervnc-debuginfo-1.8.0-1.el7.x86_64.rpm
tigervnc-server-1.8.0-1.el7.x86_64.rpm
tigervnc-server-minimal-1.8.0-1.el7.x86_64.rpm

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

aarch64:
fltk-debuginfo-1.3.4-1.el7.aarch64.rpm
fltk-devel-1.3.4-1.el7.aarch64.rpm
fltk-fluid-1.3.4-1.el7.aarch64.rpm
fltk-static-1.3.4-1.el7.aarch64.rpm
tigervnc-debuginfo-1.8.0-1.el7.aarch64.rpm
tigervnc-server-module-1.8.0-1.el7.aarch64.rpm

noarch:
tigervnc-server-applet-1.8.0-1.el7.noarch.rpm

ppc64:
fltk-debuginfo-1.3.4-1.el7.ppc.rpm
fltk-debuginfo-1.3.4-1.el7.ppc64.rpm
fltk-devel-1.3.4-1.el7.ppc.rpm
fltk-devel-1.3.4-1.el7.ppc64.rpm
fltk-fluid-1.3.4-1.el7.ppc64.rpm
fltk-static-1.3.4-1.el7.ppc.rpm
fltk-static-1.3.4-1.el7.ppc64.rpm
tigervnc-debuginfo-1.8.0-1.el7.ppc64.rpm
tigervnc-server-module-1.8.0-1.el7.ppc64.rpm

ppc64le:
fltk-debuginfo-1.3.4-1.el7.ppc64le.rpm
fltk-devel-1.3.4-1.el7.ppc64le.rpm
fltk-fluid-1.3.4-1.el7.ppc64le.rpm
fltk-static-1.3.4-1.el7.ppc64le.rpm
tigervnc-debuginfo-1.8.0-1.el7.ppc64le.rpm
tigervnc-server-module-1.8.0-1.el7.ppc64le.rpm

s390x:
fltk-debuginfo-1.3.4-1.el7.s390.rpm
fltk-debuginfo-1.3.4-1.el7.s390x.rpm
fltk-devel-1.3.4-1.el7.s390.rpm
fltk-devel-1.3.4-1.el7.s390x.rpm
fltk-fluid-1.3.4-1.el7.s390x.rpm
fltk-static-1.3.4-1.el7.s390.rpm
fltk-static-1.3.4-1.el7.s390x.rpm

x86_64:
fltk-debuginfo-1.3.4-1.el7.i686.rpm
fltk-debuginfo-1.3.4-1.el7.x86_64.rpm
fltk-devel-1.3.4-1.el7.i686.rpm
fltk-devel-1.3.4-1.el7.x86_64.rpm
fltk-fluid-1.3.4-1.el7.x86_64.rpm
fltk-static-1.3.4-1.el7.i686.rpm
fltk-static-1.3.4-1.el7.x86_64.rpm
tigervnc-debuginfo-1.8.0-1.el7.x86_64.rpm
tigervnc-server-module-1.8.0-1.el7.x86_64.rpm

Red Hat Enterprise Linux Workstation (v. 7):

Source:
fltk-1.3.4-1.el7.src.rpm
tigervnc-1.8.0-1.el7.src.rpm

noarch:
tigervnc-icons-1.8.0-1.el7.noarch.rpm
tigervnc-license-1.8.0-1.el7.noarch.rpm

x86_64:
fltk-1.3.4-1.el7.i686.rpm
fltk-1.3.4-1.el7.x86_64.rpm
fltk-debuginfo-1.3.4-1.el7.i686.rpm
fltk-debuginfo-1.3.4-1.el7.x86_64.rpm
tigervnc-1.8.0-1.el7.x86_64.rpm
tigervnc-debuginfo-1.8.0-1.el7.x86_64.rpm
tigervnc-server-1.8.0-1.el7.x86_64.rpm
tigervnc-server-minimal-1.8.0-1.el7.x86_64.rpm

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

noarch:
tigervnc-server-applet-1.8.0-1.el7.noarch.rpm

x86_64:
fltk-debuginfo-1.3.4-1.el7.i686.rpm
fltk-debuginfo-1.3.4-1.el7.x86_64.rpm
fltk-devel-1.3.4-1.el7.i686.rpm
fltk-devel-1.3.4-1.el7.x86_64.rpm
fltk-fluid-1.3.4-1.el7.x86_64.rpm
fltk-static-1.3.4-1.el7.i686.rpm
fltk-static-1.3.4-1.el7.x86_64.rpm
tigervnc-debuginfo-1.8.0-1.el7.x86_64.rpm
tigervnc-server-module-1.8.0-1.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-2016-10207
https://access.redhat.com/security/cve/CVE-2017-5581
https://access.redhat.com/security/cve/CVE-2017-7392
https://access.redhat.com/security/cve/CVE-2017-7393
https://access.redhat.com/security/cve/CVE-2017-7394
https://access.redhat.com/security/cve/CVE-2017-7395
https://access.redhat.com/security/cve/CVE-2017-7396
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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