ISC BIND DoS Vulnerability (CVE-2019-6469) - Linux

# Copyright (C) 2021 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("1.3.6.1.4.1.25623.1.0.146644");
  script_version("2021-09-06T14:01:33+0000");
  script_tag(name:"last_modification", value:"2021-09-06 14:01:33 +0000 (Mon, 06 Sep 2021)");
  script_tag(name:"creation_date", value:"2021-09-06 13:01:31 +0000 (Mon, 06 Sep 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: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:"2020-08-24 17:37:00 +0000 (Mon, 24 Aug 2020)");

  script_cve_id("CVE-2019-6469");

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

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

  script_name("ISC BIND DoS Vulnerability (CVE-2019-6469) - Linux");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2021 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 (DoS) vulnerability.");

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

  script_tag(name:"insight", value:"An error in the EDNS Client Subnet (ECS) feature for recursive
  resolvers can cause BIND to exit with an assertion failure when processing a response that has
  malformed RRSIGs.");

  script_tag(name:"impact", value:"An attacker who is able to cause a server to perform a query
  whose answer will be accompanied by malformed RRSIGs can deliberately cause a server to exit if
  it is using the recursive ECS feature.");

  script_tag(name:"affected", value:"BIND 9.10.5-S1 through 9.11.6-S1.");

  script_tag(name:"solution", value:"Update to version 9.11.7-S1 or later.");

  script_xref(name:"URL", value:"https://kb.isc.org/docs/cve-2019-6469");

  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 =~ "^9\.(10|11)\.[0-9]+s[0-9]") {
  if (version_in_range(version: version, test_version: "9.10.5s1", test_version2: "9.11.6s1")) {
    report = report_fixed_ver(installed_version: version, fixed_version: "9.11.7-S1", install_path: location);
    security_message(port: port, data: report, proto: proto);
    exit(0);
  }
}

exit(99);