ISC BIND DoS Vulnerability (CVE-2020-8620) - Linux

# Copyright (C) 2020 Greenbone Networks GmbH
# 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-or-later
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

CPE = "cpe:/a:isc:bind";

if (description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.144435");
  script_version("2021-07-07T11:00:41+0000");
  script_tag(name:"last_modification", value:"2021-07-07 11:00:41 +0000 (Wed, 07 Jul 2021)");
  script_tag(name:"creation_date", value:"2020-08-21 03:07:19 +0000 (Fri, 21 Aug 2020)");
  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:H");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2020-10-20 12:15:00 +0000 (Tue, 20 Oct 2020)");

  script_cve_id("CVE-2020-8620");

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

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

  script_name("ISC BIND DoS Vulnerability (CVE-2020-8620) - Linux");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2020 Greenbone Networks GmbH");
  script_family("Denial of Service");
  script_dependencies("gb_isc_bind_consolidation.nasl", "os_detection.nasl");
  script_mandatory_keys("isc/bind/detected", "Host/runs_unixoide");

  script_tag(name:"summary", value:"ISC BIND 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:"In versions of BIND that use the libuv network manager an incorrectly specified
  maximum buffer size allows a specially crafted large TCP payload to trigger an assertion failure when it is received.");

  script_tag(name:"impact", value:"An attacker who can establish a TCP connection with the server and send data on
  that connection can exploit this to trigger the assertion failure, causing the server to exit.");

  script_tag(name:"affected", value:"BIND 9.15.6 - 9.16.5 and 9.17.0 - 9.17.3.");

  script_tag(name:"solution", value:"Update to version 9.16.6, 9.17.4 or later.");

  script_xref(name:"URL", value:"https://kb.isc.org/docs/cve-2020-8620");

  exit(0);
}

include("host_details.inc");
include("version_func.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"];
proto = infos["proto"];
location = infos["location"];

if (version_in_range(version: version, test_version: "9.15.6", test_version2: "9.16.5")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "9.16.6", install_path: location);
  security_message(port: port, data: report, proto: proto);
  exit(0);
}

if (version_in_range(version: version, test_version: "9.17.0", test_version2: "9.17.3")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "9.17.4", install_path: location);
  security_message(port: port, data: report, proto: proto);
  exit(0);
}

exit(99);