Vulnerabilities > CVE-2018-6923 - Resource Exhaustion vulnerability in Freebsd

#
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(119887);
  script_version("1.4");
  script_cvs_date("Date: 2019/10/31 15:18:51");

  script_cve_id(
    "CVE-2018-3620",
    "CVE-2018-3646",
    "CVE-2018-6922",
    "CVE-2018-6923",
    "CVE-2018-6924",
    "CVE-2018-14526",
    "CVE-2018-15473",
    "CVE-2018-16055"
  );

  script_name(english:"pfSense 2.3.x <= 2.3.5-p2 / 2.4.x < 2.4.4 Multiple Vulnerabilities (SA-18_06 / SA-18_07 / SA-18_08)");
  script_summary(english:"Checks the version of pfSense.");

  script_set_attribute(attribute:"synopsis", value:
"The remote firewall host is affected by multiple
vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version number, the remote pfSense
install is a version 2.3.x  prior or equal to  2.3.5-p2 or 2.4.x 
prior to 2.4.3-p1. It is, therefore, affected by multiple
vulnerabilities:

 - Systems with microprocessors utilizing speculative execution and 
   address translations may allow unauthorized disclosure of 
   information residing in the L1 data cache to an attacker with 
   local user access via a terminal page fault and a side-channel 
   analysis. (CVE-2018-3620)
   
 - An authenticated command injection vulnerability exists in 
   status_interfaces.php via dhcp_relinquish_lease() in pfSense
   before 2.4.4. This allows an authenticated WebGUI user with 
   privileges for the affected page to execute commands in the 
   context of the root user when submitting a request to relinquish
   a DHCP lease for an interface which is configured to obtain its
   address via DHCP. (CVE-2018-16055)
   
 -  a denial of service vulnerability exists in the ip fragment 
    reassembly code due to excessive system resource consumption. 
    This issue can allow a remote attacker who is able to send
    arbitrary ip fragments to cause the machine to consume excessive
    resources. (CVE-2018-6923)");
  # https://www.pfsense.org/security/advisories/pfSense-SA-18_06.webgui.asc
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?c44a2d3c");
  # https://www.pfsense.org/security/advisories/pfSense-SA-18_07.webgui.asc
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?b33cf0ad");
  # https://www.pfsense.org/security/advisories/pfSense-SA-18_08.webgui.asc
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?db4f32a9");
  # https://www.netgate.com/docs/pfsense/releases/2-4-4-new-features-and-changes.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?7d4d989a");
  script_set_attribute(attribute:"solution", value:
"Upgrade to pfSense version 2.4.4 or later, or apply patches as noted
in the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:F/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:F/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2018-16055");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploit_framework_canvas", value:"true");
  script_set_attribute(attribute:"canvas_package", value:'CANVAS');

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/08/09");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/08/09");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/12/27");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:pfsense:pfsense");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:bsdperimeter:pfsense");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Firewalls");

  script_copyright(english:"This script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("pfsense_detect.nbin");
  script_require_keys("Host/pfSense");

  exit(0);
}

include("vcf.inc");
include("vcf_extras.inc");

if (!get_kb_item("Host/pfSense")) audit(AUDIT_HOST_NOT, "pfSense");

app_info = vcf::pfsense::get_app_info();
constraints = [
  {"min_version":"2.3.0", "max_version":"2.3.5-p2", "fixed_version":"2.4.4"},
  {"min_version":"2.4.0", "max_version":"2.4.3-p1", "fixed_version":"2.4.4"}
];

vcf::pfsense::check_version_and_report(
  app_info:app_info,
  constraints:constraints,
  severity:SECURITY_HOLE,
  flags:{xss:TRUE}
);

#
# (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(112070);
  script_version("1.4");
  script_cvs_date("Date: 2018/12/07  9:46:53");

  script_cve_id("CVE-2018-6923");
  script_xref(name:"FreeBSD", value:"SA-18:10.ip");

  script_name(english:"FreeBSD : FreeBSD -- Resource exhaustion in IP fragment reassembly (359e1548-a652-11e8-805b-a4badb2f4699)");
  script_summary(english:"Checks for updated packages in pkg_info output");

  script_set_attribute(
    attribute:"synopsis", 
    value:
"The remote FreeBSD host is missing one or more security-related
updates."
  );
  script_set_attribute(
    attribute:"description", 
    value:
"A researcher has notified us of a DoS attack applicable to another
operating system. While FreeBSD may not be vulnerable to that exact
attack, we have identified several places where inadequate DoS
protection could allow an attacker to consume system resources.

It is not necessary that the attacker be able to establish two-way
communication to carry out these attacks. These attacks impact both
IPv4 and IPv6 fragment reassembly. Impact : In the worst case, an
attacker could send a stream of crafted fragments with a low packet
rate which would consume a substantial amount of CPU.

Other attack vectors allow an attacker to send a stream of crafted
fragments which could consume a large amount of CPU or all available
mbuf clusters on the system.

These attacks could temporarily render a system unreachable through
network interfaces or temporarily render a system unresponsive. The
effects of the attack should clear within 60 seconds after the attack
stops."
  );
  # https://vuxml.freebsd.org/freebsd/359e1548-a652-11e8-805b-a4badb2f4699.html
  script_set_attribute(
    attribute:"see_also",
    value:"http://www.nessus.org/u?71a32ec7"
  );
  script_set_attribute(attribute:"solution", value:"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:freebsd:freebsd:FreeBSD");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:freebsd:freebsd");

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/08/14");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/08/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/08/23");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_copyright(english:"This script is Copyright (C) 2018 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", "Settings/ParanoidReport");

  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);


if (report_paranoia < 2) audit(AUDIT_PARANOID);

flag = 0;

if (pkg_test(save_report:TRUE, pkg:"FreeBSD>=11.2<11.2_2")) flag++;
if (pkg_test(save_report:TRUE, pkg:"FreeBSD>=11.1<11.1_13")) 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");