Pi-hole FTLDNS < 5.8 DNS Cache Poisoning Vulnerability

# SPDX-FileCopyrightText: 2021 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:pi-hole:ftldns";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.117320");
  script_version("2026-04-16T06:18:46+0000");
  script_tag(name:"last_modification", value:"2026-04-16 06:18:46 +0000 (Thu, 16 Apr 2026)");
  script_tag(name:"creation_date", value:"2021-04-15 11:06:07 +0000 (Thu, 15 Apr 2021)");
  script_tag(name:"cvss_base", value:"4.3");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:M/Au:N/C:N/I:P/A:N");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2021-06-04 19:04:00 +0000 (Fri, 04 Jun 2021)");

  script_cve_id("CVE-2021-3448");

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

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

  script_name("Pi-hole FTLDNS < 5.8 DNS Cache Poisoning Vulnerability");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2021 Greenbone AG");
  script_family("General");
  script_dependencies("gb_pi-hole_consolidation.nasl");
  script_mandatory_keys("pi-hole/detected");

  script_tag(name:"summary", value:"The Pi-hole FTLDNS component is prone to a DNS cache poisoning
  vulnerability.");

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

  script_tag(name:"insight", value:"The FTLDNS component is using 'dnsmasq' which is affected by
  the following flaw:

  When configured to use a specific server for a given network interface, dnsmasq uses a fixed port
  while forwarding queries. An attacker on the network, able to find the outgoing port used by
  dnsmasq, only needs to guess the random transmission ID to forge a reply and get it accepted by
  dnsmasq. This flaw makes a DNS Cache Poisoning attack much easier. The highest threat from this
  vulnerability is to data integrity.");

  script_tag(name:"affected", value:"Pi-hole FTLDNS component prior to version 5.8.");

  script_tag(name:"solution", value:"Update to version 5.8 or later.");

  script_xref(name:"URL", value:"https://pi-hole.net/2021/04/14/pi-hole-ftl-v5-8-web-v5-5-and-core-v5-3-released/");
  script_xref(name:"URL", value:"https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2021q2/014962.html");
  script_xref(name:"URL", value:"https://bugzilla.redhat.com/show_bug.cgi?id=1939368");

  exit(0);
}

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

if (!version = get_app_version(cpe: CPE, nofork: TRUE))
  exit(0);

if (version_is_less(version: version, test_version: "5.8")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "5.8");
  security_message(port: 0, data: report);
  exit(0);
}

exit(99);