Vulnerabilities > CVE-2006-2450 - Unspecified vulnerability in Libvncserver 0.7.1

047910
CVSS 7.5 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
PARTIAL
Integrity impact
PARTIAL
Availability impact
PARTIAL
network
low complexity
libvncserver
nessus

Summary

auth.c in LibVNCServer 0.7.1 allows remote attackers to bypass authentication via a request in which the client specifies an insecure security type such as "Type 1 - None", which is accepted even if it is not offered by the server, a different issue than CVE-2006-2369.

Vulnerable Configurations

Part Description Count
Application
Libvncserver
1

Nessus

  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_9DDA3FF12B0211DBA6E2000E0C2E438A.NASL
    descriptionLudwig Nussel reports that x11vnc is vulnerable to an authentication bypass vulnerability. The vulnerability is caused by an error in auth.c. This could allow a remote attacker to gain unauthorized and unauthenticated access to the system.
    last seen2020-06-01
    modified2020-06-02
    plugin id22212
    published2006-08-14
    reporterThis script is Copyright (C) 2006-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/22212
    titleFreeBSD : x11vnc -- authentication bypass vulnerability (9dda3ff1-2b02-11db-a6e2-000e0c2e438a)
    code
    #%NASL_MIN_LEVEL 80502
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were  
    # extracted from the FreeBSD VuXML database :
    #
    # Copyright 2003-2018 Jacques Vidrine and contributors
    #
    # Redistribution and use in source (VuXML) and 'compiled' forms (SGML,
    # HTML, PDF, PostScript, RTF and so forth) with or without modification,
    # are permitted provided that the following conditions are met:
    # 1. Redistributions of source code (VuXML) must retain the above
    #    copyright notice, this list of conditions and the following
    #    disclaimer as the first lines of this file unmodified.
    # 2. Redistributions in compiled form (transformed to other DTDs,
    #    published online in any format, converted to PDF, PostScript,
    #    RTF and other formats) must reproduce the above copyright
    #    notice, this list of conditions and the following disclaimer
    #    in the documentation and/or other materials provided with the
    #    distribution.
    # 
    # THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS"
    # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
    # THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
    # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
    # BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
    # OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
    # OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
    # BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
    # WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
    # OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION,
    # EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(22212);
      script_version("1.14");
      script_cvs_date("Date: 2019/08/02 13:32:38");
    
      script_cve_id("CVE-2006-2450");
      script_bugtraq_id(18977);
    
      script_name(english:"FreeBSD : x11vnc -- authentication bypass vulnerability (9dda3ff1-2b02-11db-a6e2-000e0c2e438a)");
      script_summary(english:"Checks for updated package in pkg_info output");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:"The remote FreeBSD host is missing a security-related update."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "Ludwig Nussel reports that x11vnc is vulnerable to an authentication
    bypass vulnerability. The vulnerability is caused by an error in
    auth.c. This could allow a remote attacker to gain unauthorized and
    unauthenticated access to the system."
      );
      # http://bugs.debian.org/376824
      script_set_attribute(
        attribute:"see_also",
        value:"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=376824"
      );
      # https://vuxml.freebsd.org/freebsd/9dda3ff1-2b02-11db-a6e2-000e0c2e438a.html
      script_set_attribute(
        attribute:"see_also",
        value:"http://www.nessus.org/u?2ef70d2e"
      );
      script_set_attribute(attribute:"solution", value:"Update the affected package.");
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
      script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
      script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
      script_set_attribute(attribute:"exploit_available", value:"false");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:x11vnc");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2006/08/08");
      script_set_attribute(attribute:"patch_publication_date", value:"2006/08/13");
      script_set_attribute(attribute:"plugin_publication_date", value:"2006/08/14");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2006-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
      script_family(english:"FreeBSD Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/FreeBSD/release", "Host/FreeBSD/pkg_info");
    
      exit(0);
    }
    
    
    include("audit.inc");
    include("freebsd_package.inc");
    
    
    if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
    if (!get_kb_item("Host/FreeBSD/release")) audit(AUDIT_OS_NOT, "FreeBSD");
    if (!get_kb_item("Host/FreeBSD/pkg_info")) audit(AUDIT_PACKAGE_LIST_MISSING);
    
    
    flag = 0;
    
    if (pkg_test(save_report:TRUE, pkg:"x11vnc<0.8.2")) flag++;
    
    if (flag)
    {
      if (report_verbosity > 0) security_hole(port:0, extra:pkg_report_get());
      else security_hole(0);
      exit(0);
    }
    else audit(AUDIT_HOST_NOT, "affected");
    
  • NASL familySuSE Local Security Checks
    NASL idSUSE_LIBVNCSERVER-1667.NASL
    descriptionModified clients could bypass authentication of password protected VNC servers (CVE-2006-2450).
    last seen2020-06-01
    modified2020-06-02
    plugin id27111
    published2007-10-17
    reporterThis script is Copyright (C) 2007-2019 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/27111
    titleopenSUSE 10 Security Update : LibVNCServer (LibVNCServer-1667)
    code
    #%NASL_MIN_LEVEL 80502
    
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were
    # extracted from openSUSE Security Update LibVNCServer-1667.
    #
    # The text description of this plugin is (C) SUSE LLC.
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(27111);
      script_version ("1.12");
      script_cvs_date("Date: 2019/10/25 13:36:28");
    
      script_cve_id("CVE-2006-2450");
    
      script_name(english:"openSUSE 10 Security Update : LibVNCServer (LibVNCServer-1667)");
      script_summary(english:"Check for the LibVNCServer-1667 patch");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:"The remote openSUSE host is missing a security update."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "Modified clients could bypass authentication of password protected VNC
    servers (CVE-2006-2450)."
      );
      script_set_attribute(
        attribute:"solution", 
        value:"Update the affected LibVNCServer package."
      );
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:novell:opensuse:LibVNCServer");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:novell:opensuse:10.1");
    
      script_set_attribute(attribute:"patch_publication_date", value:"2006/06/18");
      script_set_attribute(attribute:"plugin_publication_date", value:"2007/10/17");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2007-2019 Tenable Network Security, Inc.");
      script_family(english:"SuSE Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/SuSE/release", "Host/SuSE/rpm-list", "Host/cpu");
    
      exit(0);
    }
    
    
    include("audit.inc");
    include("global_settings.inc");
    include("rpm.inc");
    
    if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
    release = get_kb_item("Host/SuSE/release");
    if (isnull(release) || release =~ "^(SLED|SLES)") audit(AUDIT_OS_NOT, "openSUSE");
    if (release !~ "^(SUSE10\.1)$") audit(AUDIT_OS_RELEASE_NOT, "openSUSE", "10.1", release);
    if (!get_kb_item("Host/SuSE/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
    
    ourarch = get_kb_item("Host/cpu");
    if (!ourarch) audit(AUDIT_UNKNOWN_ARCH);
    if (ourarch !~ "^(i586|i686|x86_64)$") audit(AUDIT_ARCH_NOT, "i586 / i686 / x86_64", ourarch);
    
    flag = 0;
    
    if ( rpm_check(release:"SUSE10.1", reference:"LibVNCServer-0.7.99-15.3") ) flag++;
    
    if (flag)
    {
      if (report_verbosity > 0) security_hole(port:0, extra:rpm_report_get());
      else security_hole(0);
      exit(0);
    }
    else
    {
      tested = pkg_tests_get();
      if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
      else audit(AUDIT_PACKAGE_NOT_INSTALLED, "LibVNCServer");
    }
    
  • NASL familyGentoo Local Security Checks
    NASL idGENTOO_GLSA-200608-12.NASL
    descriptionThe remote host is affected by the vulnerability described in GLSA-200608-12 (x11vnc: Authentication bypass in included LibVNCServer code) x11vnc includes vulnerable LibVNCServer code, which fails to properly validate protocol types effectively letting users decide what protocol to use, such as
    last seen2020-06-01
    modified2020-06-02
    plugin id22171
    published2006-08-08
    reporterThis script is Copyright (C) 2006-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/22171
    titleGLSA-200608-12 : x11vnc: Authentication bypass in included LibVNCServer code
    code
    #%NASL_MIN_LEVEL 80502
    #
    # (C) Tenable Network Security, Inc.
    #
    # The descriptive text and package checks in this plugin were
    # extracted from Gentoo Linux Security Advisory GLSA 200608-12.
    #
    # The advisory text is Copyright (C) 2001-2018 Gentoo Foundation, Inc.
    # and licensed under the Creative Commons - Attribution / Share Alike 
    # license. See http://creativecommons.org/licenses/by-sa/3.0/
    #
    
    include("compat.inc");
    
    if (description)
    {
      script_id(22171);
      script_version("1.16");
      script_cvs_date("Date: 2019/08/02 13:32:43");
    
      script_cve_id("CVE-2006-2450");
      script_xref(name:"GLSA", value:"200608-12");
    
      script_name(english:"GLSA-200608-12 : x11vnc: Authentication bypass in included LibVNCServer code");
      script_summary(english:"Checks for updated package(s) in /var/db/pkg");
    
      script_set_attribute(
        attribute:"synopsis", 
        value:
    "The remote Gentoo host is missing one or more security-related
    patches."
      );
      script_set_attribute(
        attribute:"description", 
        value:
    "The remote host is affected by the vulnerability described in GLSA-200608-12
    (x11vnc: Authentication bypass in included LibVNCServer code)
    
        x11vnc includes vulnerable LibVNCServer code, which fails to properly
        validate protocol types effectively letting users decide what protocol
        to use, such as 'Type 1 - None' (GLSA-200608-05). x11vnc will accept
        this security type, even if it is not offered by the server.
      
    Impact :
    
        An attacker could exploit this vulnerability to gain unauthorized
        access with the privileges of the user running the VNC server.
      
    Workaround :
    
        There is no known workaround at this time."
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://security.gentoo.org/glsa/200608-05"
      );
      script_set_attribute(
        attribute:"see_also",
        value:"https://security.gentoo.org/glsa/200608-12"
      );
      script_set_attribute(
        attribute:"solution", 
        value:
    "All x11vnc users should upgrade to the latest version:
        # emerge --sync
        # emerge --ask --oneshot --verbose '>=x11-misc/x11vnc-0.8.1'"
      );
      script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:gentoo:linux:x11vnc");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:gentoo:linux");
    
      script_set_attribute(attribute:"patch_publication_date", value:"2006/08/07");
      script_set_attribute(attribute:"plugin_publication_date", value:"2006/08/08");
      script_end_attributes();
    
      script_category(ACT_GATHER_INFO);
      script_copyright(english:"This script is Copyright (C) 2006-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");
      script_family(english:"Gentoo Local Security Checks");
    
      script_dependencies("ssh_get_info.nasl");
      script_require_keys("Host/local_checks_enabled", "Host/Gentoo/release", "Host/Gentoo/qpkg-list");
    
      exit(0);
    }
    
    
    include("audit.inc");
    include("global_settings.inc");
    include("qpkg.inc");
    
    if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
    if (!get_kb_item("Host/Gentoo/release")) audit(AUDIT_OS_NOT, "Gentoo");
    if (!get_kb_item("Host/Gentoo/qpkg-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
    
    
    flag = 0;
    
    if (qpkg_check(package:"x11-misc/x11vnc", unaffected:make_list("ge 0.8.1"), vulnerable:make_list("lt 0.8.1"))) flag++;
    
    if (flag)
    {
      if (report_verbosity > 0) security_hole(port:0, extra:qpkg_report_get());
      else security_hole(0);
      exit(0);
    }
    else
    {
      tested = qpkg_tests_get();
      if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
      else audit(AUDIT_PACKAGE_NOT_INSTALLED, "x11vnc");
    }
    
  • NASL familyGentoo Local Security Checks
    NASL idGENTOO_GLSA-200608-05.NASL
    descriptionThe remote host is affected by the vulnerability described in GLSA-200608-05 (LibVNCServer: Authentication bypass) LibVNCServer fails to properly validate protocol types effectively letting users decide what protocol to use, such as
    last seen2020-06-01
    modified2020-06-02
    plugin id22147
    published2006-08-04
    reporterThis script is Copyright (C) 2006-2019 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/22147
    titleGLSA-200608-05 : LibVNCServer: Authentication bypass
  • NASL familyMisc.
    NASL idREALVNC_AUTH_BYPASS.NASL
    descriptionThe version of VNC server running on the remote host is affected by the following vulnerabilities : - A flaw exists in RealVNC due to an error when handling password authentication. A remote attacker can exploit this to bypass authentication by using a specially crafted request in which the client specifies an insecure security type (e.g.,
    last seen2020-06-01
    modified2020-06-02
    plugin id21564
    published2006-05-15
    reporterThis script is Copyright (C) 2006-2018 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/21564
    titleVNC Security Type Enforcement Failure Remote Authentication Bypass
  • NASL familySuSE Local Security Checks
    NASL idSUSE_XEN-1841.NASL
    descriptionModified clients could bypass authentication of password protected VNC servers (CVE-2006-2450).
    last seen2020-06-01
    modified2020-06-02
    plugin id27481
    published2007-10-17
    reporterThis script is Copyright (C) 2007-2019 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/27481
    titleopenSUSE 10 Security Update : xen (xen-1841)
  • NASL familyGentoo Local Security Checks
    NASL idGENTOO_GLSA-200703-19.NASL
    descriptionThe remote host is affected by the vulnerability described in GLSA-200703-19 (LTSP: Authentication bypass in included LibVNCServer code) The LTSP server includes vulnerable LibVNCServer code, which fails to properly validate protocol types effectively letting users decide what protocol to use, such as
    last seen2020-06-01
    modified2020-06-02
    plugin id24868
    published2007-03-19
    reporterThis script is Copyright (C) 2007-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/24868
    titleGLSA-200703-19 : LTSP: Authentication bypass in included LibVNCServer code

Statements

contributorMark J Cox
lastmodified2006-08-24
organizationRed Hat
statementNot vulnerable. This issue does not affect the versions of LibVNCServer as distributed with Red Hat Enterprise Linux 2.1, 3, or 4.