Elastic Beats filebeat 8.0.x < 8.19.18 / 9.0.x < 9.3.1 DoS (ESA-2026-165)

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

include('compat.inc');

if (description)
{
  script_id(342651);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/09/04");

  script_cve_id("CVE-2026-78588");

  script_name(english:"Elastic Beats filebeat 8.0.x < 8.19.18 / 9.0.x < 9.3.1 DoS (ESA-2026-165)");

  script_set_attribute(attribute:"synopsis", value:
"Elastic Beats filebeat installed on the remote Windows host is affected by a denial of service vulnerability.");
  script_set_attribute(attribute:"description", value:
"The version of Elastic Beats filebeat installed on the remote host is 8.0.x prior to 8.19.18, or 9.0.x prior to 9.3.1.
It is, therefore, affected by a denial of service vulnerability.

  - Allocation of Resources Without Limits or Throttling (CWE-770) in Filebeat can lead to a denial of service
    via Excessive Allocation (CAPEC-130). An attacker able to reach the Filebeat HTTP ingestion endpoint could
    send specially crafted compressed requests that exhaust the memory resources of the Filebeat process.
    (CVE-2026-78588)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  # https://discuss.elastic.co/t/filebeat-8-19-18-9-3-1-security-update-esa-2026-165/390118
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?307dc201");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Elastic Beats filebeat version 8.19.18, 9.3.1 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/I:N/A:C");
  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:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-78588");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(770);

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/09/02");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/09/01");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/09/03");

  script_set_attribute(attribute:"potential_vulnerability", value:"true");
  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"x-cpe:/a:elastic:beats_filebeat");
  script_end_attributes();

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

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

  script_dependencies("elastic_beats_filebeat_win_installed.nbin");
  script_require_keys("installed_sw/Beats filebeat", "SMB/Registry/Enumerated", "Settings/ParanoidReport");

  exit(0);
}

include('vdf.inc');

# Only deployments that explicitly enabled the HTTP endpoint input are affected; this cannot be checked remotely.
if (report_paranoia < 2) audit(AUDIT_PARANOID);

# @tvdl-content
var vuln_data = {
  'metadata': {'spec_version': '1.0'},
  'requires': [
    {'scope': 'target', 'match': {'os': 'windows'}},
    {'scope': 'target', 'match': {'paranoia': true}}
  ],
  'checks': [
    {
      'product': {'name': 'Beats filebeat', 'type': 'app'},
      'check_algorithm': 'default',
      'potential_vulnerability': {
        'missing_config_check': true
      },
      'constraints': [
        {'min_version': '8.0.0', 'fixed_version': '8.19.18'},
        {'min_version': '9.0.0', 'fixed_version': '9.3.1'}
      ]
    }
  ]
};

var result = vdf::check_and_report(vuln_data:vuln_data, severity:SECURITY_WARNING);
vdf::handle_check_and_report_errors(vdf_result:result);