Fortinet FortiOS 4.3.x < 4.3.19 TLS and IPSEC Information Disclosure

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

include('compat.inc');

if (description)
{
  script_id(95440);
  script_version("1.9");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/01/15");

  script_cve_id("CVE-2016-8492");
  script_bugtraq_id(94480);

  script_name(english:"Fortinet FortiOS 4.3.x < 4.3.19 TLS and IPSEC Information Disclosure");

  script_set_attribute(attribute:"synopsis", value:
"The remote host is affected by an information disclosure
vulnerability.");
  script_set_attribute(attribute:"description", value:
"The remote FortiGate device is running a version of FortiOS that is
4.3.x prior to 4.2.19. It is, therefore, affected by a flaw due to
the implementation the ANSI X9.31 RNG that is used to decrypt TLS and
IPSec traffic. A man-in-the-middle (MitM) attacker can exploit this to
disclose sensitive information.");
  # http://fortiguard.com/advisory/implementation-of-ctr-drbg-rng-in-fortios-4-3
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?fb9373c0");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Fortinet FortiOS version 4.3.19 / 5.0 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:P/I:N/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2016-8492");
  script_set_attribute(attribute:"cvss3_score_rationale", value:"Scoring adjustsed to align with CVSS 3.1 attack complexity guidance.");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2016/11/22");
  script_set_attribute(attribute:"patch_publication_date", value:"2016/11/22");
  script_set_attribute(attribute:"plugin_publication_date", value:"2016/12/01");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:fortinet:fortios");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2016-2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("fortinet_version.nbin");
  script_require_keys("Host/Fortigate/model", "Host/Fortigate/version");

  exit(0);
}

include("audit.inc");
include("global_settings.inc");
include("misc_func.inc");

app_name = "FortiOS";

version = get_kb_item_or_exit("Host/Fortigate/version");
model = get_kb_item_or_exit("Host/Fortigate/model");

# Make sure device is FortiGate
if (!preg(string:model, pattern:"fortigate", icase:TRUE)) audit(AUDIT_HOST_NOT, "a FortiGate");

if (version =~ "^4\.3\.") fix = "4.3.19";
else audit(AUDIT_INST_VER_NOT_VULN, app_name, version);

if (ver_compare(ver:version, fix:fix, strict:FALSE) == -1)
{
  report =
    '\n  Model             : ' + model +
    '\n  Installed version : ' + version +
    '\n  Fixed version     : ' + fix +
    '\n';
  security_report_v4(severity:SECURITY_WARNING, extra:report, port:0);
}
else audit(AUDIT_INST_VER_NOT_VULN, app_name, version);