RHEL 7 : tigervnc and fltk (RHSA-2017:2000)

critical Nessus Plugin ID 102109

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Synopsis

The remote Red Hat host is missing one or more security updates.

Description

The remote Redhat Enterprise Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2017:2000 advisory.

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.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

Plugin Details

Severity: Critical

ID: 102109

File Name: redhat-RHSA-2017-2000.nasl

Version: 3.13

Type: local

Agent: unix

Family: Red Hat Local Security Checks

Published: 8/2/2017

Updated: 4/15/2025

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

Vendor

Vendor Severity: Moderate

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2017-5581

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:tigervnc, p-cpe:/a:redhat:enterprise_linux:fltk-devel, cpe:/o:redhat:enterprise_linux:7, p-cpe:/a:redhat:enterprise_linux:tigervnc-server-module, p-cpe:/a:redhat:enterprise_linux:tigervnc-license, p-cpe:/a:redhat:enterprise_linux:tigervnc-server-minimal, p-cpe:/a:redhat:enterprise_linux:tigervnc-server, p-cpe:/a:redhat:enterprise_linux:tigervnc-server-applet, p-cpe:/a:redhat:enterprise_linux:tigervnc-icons, p-cpe:/a:redhat:enterprise_linux:fltk-static, p-cpe:/a:redhat:enterprise_linux:fltk, p-cpe:/a:redhat:enterprise_linux:fltk-fluid

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Ease: No known exploits are available

Patch Publication Date: 8/1/2017

Vulnerability Publication Date: 2/28/2017

Reference Information

CVE: CVE-2016-10207, CVE-2017-5581, CVE-2017-7392, CVE-2017-7393, CVE-2017-7394, CVE-2017-7395, CVE-2017-7396

CWE: 119, 190, 416

RHSA: 2017:2000

Detections

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