Vulnerabilities > CVE-2005-2534 - Denial Of Service vulnerability in OpenVPN Same Client Certificate

047910
CVSS 2.6 - LOW
Attack vector
NETWORK
Attack complexity
HIGH
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
PARTIAL
network
high complexity
openvpn
nessus

Summary

Race condition in OpenVPN before 2.0.1, when --duplicate-cn is not enabled, allows remote attackers to cause a denial of service (server crash) via simultaneous TCP connections from multiple clients that use the same client certificate.

Vulnerable Configurations

Part Description Count
Application
Openvpn
74

Nessus

  • NASL familyFreeBSD Local Security Checks
    NASL idFREEBSD_PKG_5AD3E437E5274514B9ED280B2CA1A8C9.NASL
    descriptionJames Yonan reports : If two or more client machines try to connect to the server at the same time via TCP, using the same client certificate, and when --duplicate-cn is not enabled on the server, a race condition can crash the server with
    last seen2020-06-01
    modified2020-06-02
    plugin id21433
    published2006-05-13
    reporterThis script is Copyright (C) 2006-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/21433
    titleFreeBSD : openvpn -- multiple TCP clients connecting with the same certificate at the same time can crash the server (5ad3e437-e527-4514-b9ed-280b2ca1a8c9)
    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 2003-2019 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(21433);
      script_version("1.13");
      script_cvs_date("Date: 2019/08/02 13:32:37");
    
      script_cve_id("CVE-2005-2534");
    
      script_name(english:"FreeBSD : openvpn -- multiple TCP clients connecting with the same certificate at the same time can crash the server (5ad3e437-e527-4514-b9ed-280b2ca1a8c9)");
      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:
    "James Yonan reports :
    
    If two or more client machines try to connect to the server at the
    same time via TCP, using the same client certificate, and when
    --duplicate-cn is not enabled on the server, a race condition can
    crash the server with 'Assertion failed at mtcp.c:411'"
      );
      # http://openvpn.net/changelog.html
      script_set_attribute(
        attribute:"see_also",
        value:"https://openvpn.net/community-resources/changelog-for-openvpn-2-1/"
      );
      # https://vuxml.freebsd.org/freebsd/5ad3e437-e527-4514-b9ed-280b2ca1a8c9.html
      script_set_attribute(
        attribute:"see_also",
        value:"http://www.nessus.org/u?826f2385"
      );
      script_set_attribute(attribute:"solution", value:"Update the affected package.");
      script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:N/I:N/A:P");
    
      script_set_attribute(attribute:"plugin_type", value:"local");
      script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:openvpn");
      script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");
    
      script_set_attribute(attribute:"vuln_publication_date", value:"2005/08/03");
      script_set_attribute(attribute:"patch_publication_date", value:"2005/08/19");
      script_set_attribute(attribute:"plugin_publication_date", value:"2006/05/13");
      script_set_attribute(attribute:"generated_plugin", value:"current");
      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:"openvpn<2.0.1")) flag++;
    
    if (flag)
    {
      if (report_verbosity > 0) security_note(port:0, extra:pkg_report_get());
      else security_note(0);
      exit(0);
    }
    else audit(AUDIT_HOST_NOT, "affected");
    
  • NASL familyWindows
    NASL idOPENVPN_2_0_1.NASL
    descriptionAccording to its self-reported version number, the version of OpenVPN installed on the remote Windows host is prior to 2.0.1. It is, therefore, affected by multiple vulnerabilities: - A denial of service (DoS) vulnerability exists in OpenVPN due to its OpenSSL error queue not being flushed properly. An unauthenticated, remote attacker can exploit this issue, by sending a large number of incorrect connection requests, to cause the application to stop responding (CVE-2005-2531) & (CVE-2005-2532). - OpenVPN is affected by a denial of service (DoS) vulnerability. An authenticated, remote attacker can exploit this issue, by sending a large of number of packets with spoofed MAC addresses, to cause the application to stop responding (CVE-2005-2533). - A denial of service (DoS) vulnerability exists in OpenVPN when --duplicate-cn is not enabled. An unauthenticated, remote attacker can exploit this issue, by issuing simultaneous tcp connections from multiple clients that use the same certificate, to cause the application to stop responding (CVE-2005-2534).
    last seen2020-06-01
    modified2020-06-02
    plugin id125261
    published2019-05-17
    reporterThis script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/125261
    titleOpenVPN < 2.0.1 Multiple Vulnerabilities (Windows)
  • NASL familyDebian Local Security Checks
    NASL idDEBIAN_DSA-851.NASL
    descriptionSeveral security related problems have been discovered in openvpn, a Virtual Private Network daemon. The Common Vulnerabilities and Exposures project identifies the following problems : - CAN-2005-2531 Wrong processing of failed certificate authentication when running with
    last seen2020-06-01
    modified2020-06-02
    plugin id19959
    published2005-10-11
    reporterThis script is Copyright (C) 2005-2019 Tenable Network Security, Inc.
    sourcehttps://www.tenable.com/plugins/nessus/19959
    titleDebian DSA-851-1 : openvpn - programming errors