NTP.org 'ntpd' 4.2.5p203 - 4.2.8p8, 4.3.0 - 4.3.93 DoS Vulnerability (Nov 2016)

# SPDX-FileCopyrightText: 2016 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:ntp:ntp";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.106409");
  script_version("2024-02-23T14:36:45+0000");
  script_cve_id("CVE-2016-7426");
  script_tag(name:"last_modification", value:"2024-02-23 14:36:45 +0000 (Fri, 23 Feb 2024)");
  script_tag(name:"creation_date", value:"2016-06-03 11:18:33 +0700 (Fri, 03 Jun 2016)");
  script_tag(name:"cvss_base", value:"4.3");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:M/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:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2020-06-18 18:14:00 +0000 (Thu, 18 Jun 2020)");
  script_name("NTP.org 'ntpd' 4.2.5p203 - 4.2.8p8, 4.3.0 - 4.3.93 DoS Vulnerability (Nov 2016)");
  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2016 Greenbone AG");
  script_family("Denial of Service");
  script_dependencies("ntp_open.nasl", "gb_ntp_detect_lin.nasl");
  script_mandatory_keys("ntpd/version/detected");

  script_xref(name:"URL", value:"https://www.kb.cert.org/vuls/id/633847");

  script_tag(name:"summary", value:"NTP.org's reference implementation of NTP server, ntpd, is prone to a
  denial of service vulnerability.");

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

  script_tag(name:"insight", value:"When ntpd is configured with rate limiting for all associations (restrict
  default limited in ntp.conf), the limits are applied also to responses received from its configured sources. An
  attacker who knows the sources (e.g., from an IPv4 refid in server response) and knows the system is
  (mis)configured in this way can periodically send packets with spoofed source address to keep the rate limiting
  activated and prevent ntpd from accepting valid responses from its sources.");

  script_tag(name:"impact", value:"A remote attacker may be able to perform a denial of service on ntpd.");

  script_tag(name:"affected", value:"NTPd version 4.2.5p203 up to 4.2.8p8, 4.3.0 up to 4.3.93.");

  script_tag(name:"solution", value:"Update to version 4.2.8p9, 4.3.94 or later.");

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

  exit(0);
}

include("version_func.inc");
include("revisions-lib.inc");
include("host_details.inc");

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

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

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

if ((revcomp(a: version, b: "4.2.5p203") >= 0) && (revcomp(a: version, b: "4.2.8p9") < 0)) {
  report = report_fixed_ver(installed_version: version, fixed_version: "4.2.8p9", install_path: location);
  security_message(port: port, proto: proto, data: report);
  exit(0);
}

if ((revcomp(a: version, b: "4.3.0") >= 0) && (revcomp(a: version, b: "4.3.94") < 0)) {
  report = report_fixed_ver(installed_version: version, fixed_version: "4.3.94", install_path: location);
  security_message(port: port, proto: proto, data: report);
  exit(0);
}

exit(99);