Apache Tomcat 'HTTP2' Denial of Service Vulnerability - Linux

# SPDX-FileCopyrightText: 2017 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:apache:tomcat";

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.811702");
  script_version("2024-02-15T05:05:40+0000");
  script_cve_id("CVE-2016-6817");
  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:"last_modification", value:"2024-02-15 05:05:40 +0000 (Thu, 15 Feb 2024)");
  script_tag(name:"severity_vector", value:"CVSS:3.0/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:"2019-04-15 16:30:00 +0000 (Mon, 15 Apr 2019)");
  script_tag(name:"creation_date", value:"2017-08-11 16:00:14 +0530 (Fri, 11 Aug 2017)");
  script_tag(name:"qod_type", value:"remote_banner_unreliable");
  script_name("Apache Tomcat 'HTTP2' Denial of Service Vulnerability - Linux");

  script_tag(name:"summary", value:"Apache Tomcat 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:"The flaw exists due to error in  HTTP2 header
  parser in Apache Tomcat which enters an infinite loop if a header was received
  that was larger than the available buffer.");

  script_tag(name:"impact", value:"Successful exploitation will allow remote
  attackers to conduct a denial-of-service condition.");

  script_tag(name:"affected", value:"Apache Tomcat versions 9.0.0.M1 to 9.0.0.M11,
  Apache Tomcat versions 8.5.0 to 8.5.6 on Linux.");

  script_tag(name:"solution", value:"Upgrade to Apache Tomcat version
  9.0.0.M13 or 8.5.8 or later.");

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

  script_xref(name:"URL", value:"http://tomcat.apache.org/security-8.html#Fixed_in_Apache_Tomcat_8.5.8");
  script_xref(name:"URL", value:"http://www.securityfocus.com/bid/94462");
  script_xref(name:"URL", value:"http://tomcat.apache.org/security-9.html#Fixed_in_Apache_Tomcat_9.0.0.M13");

  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2017 Greenbone AG");
  script_family("Web Servers");
  script_dependencies("gb_apache_tomcat_consolidation.nasl", "os_detection.nasl");
  script_mandatory_keys("apache/tomcat/detected", "Host/runs_unixoide");
  exit(0);
}

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

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

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

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

if(appVer =~ "^8\.5\.")
{
  if(revcomp(a: appVer, b: "8.5.8") < 0){
    fix = "8.5.8";
  }
}

else if(appVer =~ "^9\.")
{
  if(revcomp(a: appVer, b: "9.0.0.M13") < 0){
    fix = "9.0.0.M13";
  }
}

if(fix)
{
  report = report_fixed_ver(installed_version:appVer, fixed_version:fix, install_path:path);
  security_message(data:report, port:tomPort);
  exit(0);
}
exit(0);