Unbound DNS Resolver < 1.21.1 DoS Vulnerability

# SPDX-FileCopyrightText: 2024 Greenbone AG
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-only

CPE = "cpe:/a:nlnetlabs:unbound";

if (description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.124700");
  script_version("2025-10-31T05:40:56+0000");
  script_tag(name:"last_modification", value:"2025-10-31 05:40:56 +0000 (Fri, 31 Oct 2025)");
  script_tag(name:"creation_date", value:"2024-10-07 02:36:43 +0000 (Mon, 07 Oct 2024)");
  script_tag(name:"cvss_base", value:"5.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:N/I:N/A:P");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2024-12-17 19:28:03 +0000 (Tue, 17 Dec 2024)");

  script_cve_id("CVE-2024-8508");

  script_tag(name:"qod_type", value:"remote_banner_unreliable");

  script_tag(name:"solution_type", value:"VendorFix");

  script_name("Unbound DNS Resolver < 1.21.1 DoS Vulnerability");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2024 Greenbone AG");
  script_family("Denial of Service");
  script_dependencies("gb_unbound_dns_detect.nasl");
  script_mandatory_keys("unbound/detected");

  script_tag(name:"summary", value:"Unbound DNS Resolver is prone to a denial of service (DoS)
  vulnerability.");

  script_tag(name:"vuldetect", value:"Checks if a vulnerable version is present on the target host.");

  script_tag(name:"insight", value:"Malicious upstreams responses with very large RRsets can cause
  Unbound to spend a considerable time applying name compression to downstream replies. This can
  lead to degraded performance and eventually denial of service in well orchestrated attacks.");

  script_tag(name:"affected", value:"Unbound DNS Resolver version prior to 1.21.1.");

  script_tag(name:"solution", value:"Update to version 1.21.1 or later.");

  script_xref(name:"URL", value:"https://www.nlnetlabs.nl/downloads/unbound/CVE-2024-8508.txt");

  exit(0);
}

include("host_details.inc");
include("version_func.inc");

if (!port = get_app_port(cpe: CPE))
  exit(0);

if (!infos = get_app_version_and_proto(cpe: CPE, port: port, exit_no_version: TRUE))
  exit(0);

version = infos["version"];
proto = infos["proto"];

if (version_is_less(version: version, test_version: "1.21.1")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "1.21.1");
  security_message(port: port, data: report, proto: proto);
  exit(0);
}

exit(99);