Fortinet Fortigate - Padding oracle in cookie encryption (FG-IR-21-126)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(171888);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/03/10");

  script_cve_id("CVE-2021-43074");
  script_xref(name:"IAVA", value:"2023-A-0110-S");

  script_name(english:"Fortinet Fortigate - Padding oracle in cookie encryption (FG-IR-21-126)");

  script_set_attribute(attribute:"synopsis", value:
"Fortinet Firewall is missing one or more security-related updates.");
  script_set_attribute(attribute:"description", value:
"The version of Fortigate installed on the remote host is prior to tested version. It is, therefore, affected by a
vulnerability as referenced in the FG-IR-21-126 advisory.

  - An improper verification of cryptographic signature vulnerability [CWE-347] in FortiOS may allow an attacker to
    decrypt portions of the administrative session management cookie if able to intercept the latter.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://www.fortiguard.com/psirt/FG-IR-21-126");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Fortigate version 6.4.9 / 7.0.4 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/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:L/PR:L/UI:N/S:U/C:L/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-2021-43074");

  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:"2023/02/16");
  script_set_attribute(attribute:"patch_publication_date", value:"2023/02/16");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/02/24");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:fortinet:fortiproxy");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2023 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('vcf.inc');
include('vcf_extras_fortios.inc');

var app_name = 'Fortigate';
var app_info = vcf::get_app_info(app:app_name, kb_ver:'Host/Fortigate/version');
vcf::fortios::verify_product_and_model(product_name:app_name);

var constraints = [
  { 'min_version' : '6.0', 'fixed_version' : '6.4.9' },
  { 'min_version' : '7.0.0', 'fixed_version' : '7.0.4' }
];

vcf::check_version_and_report(app_info:app_info, constraints:constraints, severity:SECURITY_WARNING);