Apache Tomcat DoS Vulnerability (Jul 2021) - 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:apache:tomcat";

if (description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.146268");
  script_version("2021-08-24T09:01:06+0000");
  script_tag(name:"last_modification", value:"2021-08-24 09:01:06 +0000 (Tue, 24 Aug 2021)");
  script_tag(name:"creation_date", value:"2021-07-13 05:45:15 +0000 (Tue, 13 Jul 2021)");
  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:"2021-07-15 18:05:00 +0000 (Thu, 15 Jul 2021)");

  script_cve_id("CVE-2021-30639");

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

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

  script_name("Apache Tomcat DoS Vulnerability (Jul 2021) - Linux");

  script_category(ACT_GATHER_INFO);

  script_copyright("Copyright (C) 2021 Greenbone Networks GmbH");
  script_family("Web Servers");
  script_dependencies("gb_apache_tomcat_consolidation.nasl", "os_detection.nasl");
  script_mandatory_keys("apache/tomcat/detected", "Host/runs_unixoide");

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

  script_tag(name:"insight", value:"An error introduced as part of a change to improve error handling
  during non-blocking I/O means that the error flag associated with the Request object is not reset
  between requests. This means that once a non-blocking I/O error occurres, all future requests
  handled by that request object will fail. Users are able to trigger non-blocking I/O errors,
  e.g. by dropping a connection, thereby creating the possibility of triggering a DoS.

  Applications that do not use non-blocking I/O are not exposed to this vulnerability.");

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

  script_tag(name:"affected", value:"Apache Tomcat 8.5.64, 9.0.44 and 10.0.3 through 10.0.4.");

  script_tag(name:"solution", value:"Update to version 8.5.65, 9.0.45, 10.0.5 or later.");

  script_xref(name:"URL", value:"https://lists.apache.org/thread.html/rd84fae1f474597bdf358f5bdc0a5c453c507bd527b83e8be6b5ea3f4%40%3Cannounce.tomcat.apache.org%3E");
  script_xref(name:"URL", value:"https://tomcat.apache.org/security-10.html#Fixed_in_Apache_Tomcat_10.0.5");
  script_xref(name:"URL", value:"https://tomcat.apache.org/security-9.html#Fixed_in_Apache_Tomcat_9.0.45");
  script_xref(name:"URL", value:"https://tomcat.apache.org/security-8.html#Fixed_in_Apache_Tomcat_8.5.65");

  exit(0);
}

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

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

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

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

if (version == "8.5.64") {
  report = report_fixed_ver(installed_version: version, fixed_version: "8.5.65", install_path: location);
  security_message(port: port, data: report);
  exit(0);
}

if (version == "9.0.44") {
  report = report_fixed_ver(installed_version: version, fixed_version: "9.0.45", install_path: location);
  security_message(port: port, data: report);
  exit(0);
}

if (version_in_range(version: version, test_version: "10.0.3", test_version2: "10.0.4")) {
  report = report_fixed_ver(installed_version: version, fixed_version: "10.0.5", install_path: location);
  security_message(port: port, data: report);
  exit(0);
}

exit(99);