Fortinet FortiWeb Pre-authentication DoS attack in OpenSSH - CVE-2025-26466 (FG-IR-25-122)

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

include('compat.inc');

if (description)
{
  script_id(275778);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2025/11/19");

  script_cve_id("CVE-2025-26466");

  script_name(english:"Fortinet FortiWeb Pre-authentication DoS attack in OpenSSH - CVE-2025-26466 (FG-IR-25-122)");

  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 FortiWeb installed on the remote host is prior to tested version. It is, therefore, affected by a
vulnerability as referenced in the FG-IR-25-122 advisory.

  - A flaw was found in the OpenSSH package. For each ping packet the SSH server receives, a pong packet is
    allocated in a memory buffer and stored in a queue of packages. It is only freed when the server/client
    key exchange has finished. A malicious client may keep sending such packages, leading to an uncontrolled
    increase in memory consumption on the server side. Consequently, the server may become unavailable,
    resulting in a denial of service attack. (CVE-2025-26466)

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-25-122");
  script_set_attribute(attribute:"see_also", value:"https://www.qualys.com/2025/02/18/openssh-mitm-dos.txt");
  script_set_attribute(attribute:"solution", value:
"For 7.6.x, upgrade to FortiWeb version 7.6.5 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:H/Au:N/C:N/I:N/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2025-26466");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2023/12/12");
  script_set_attribute(attribute:"patch_publication_date", value:"2025/03/11");
  script_set_attribute(attribute:"plugin_publication_date", value:"2025/11/19");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:fortinet:fortiweb");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2025 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_extras_fortios.inc');

var app_name = 'FortiWeb';
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' : '7.6.0', 'max_version' : '7.6.4', 'fixed_version' : '7.6.5' }
];

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