FCKeditor.Java Connector Servlet 'CurrentFolder' Infinite Loop DoS

#%NASL_MIN_LEVEL 70300
#
# (C) Tenable Network Security, Inc.
#

include('deprecated_nasl_level.inc');
include('compat.inc');

if (description)
{
  script_id(39875);
  script_version("1.18");
  script_set_attribute(attribute:"plugin_modification_date", value:"2022/04/11");

  script_cve_id("CVE-2009-4875");
  script_bugtraq_id(35709);
  script_xref(name:"SECUNIA", value:"35870");

  script_name(english:"FCKeditor.Java Connector Servlet 'CurrentFolder' Infinite Loop DoS");

  script_set_attribute(attribute:"synopsis", value:
"A web application running on the remote host has a denial of service
vulnerability.");
  script_set_attribute(attribute:"description", value:
"The remote web server is hosting a web application that uses
FCKeditor.Java, which is used to run FCKeditor in a Java environment.

Input to the 'CurrentFolder' parameter of the connector servlet is
not sanitized properly.  It is possible to create a specially crafted
request that could put the web server into an infinite loop.  A
remote attacker could use this to create a denial of service.");
  script_set_attribute(attribute:"see_also", value:"https://dev.ckeditor.com/ticket/3902");
  script_set_attribute(attribute:"see_also", value:"http://sourceforge.net/project/shownotes.php?release_id=697258");
  script_set_attribute(attribute:"see_also", value:"http://java.fckeditor.net/changes-report.html");
  script_set_attribute(attribute:"solution", value:
"Upgrade to FCKeditor.Java version 2.4.2 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2009/07/07");
  script_set_attribute(attribute:"patch_publication_date", value:"2009/07/15");
  script_set_attribute(attribute:"plugin_publication_date", value:"2009/07/20");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"thorough_tests", value:"true");
  script_end_attributes();

  script_category(ACT_ATTACK);
  script_family(english:"CGI abuses");

  script_copyright(english:"This script is Copyright (C) 2009-2022 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("webmirror.nasl", "http_version.nasl");
  script_exclude_keys("Settings/disable_cgi_scanning");
  script_require_ports("Services/www", 8080);

  exit(0);
}

#

include("global_settings.inc");
include("misc_func.inc");
include("http.inc");


port = get_http_port(default:8080);
vuln_urls = make_list();

# FCKeditor.Java could be used with any JSP web app...there doesn't seem to be
# a reliable way of detecting it
if (thorough_tests)
{
  dirs = get_kb_list('www/' + port + '/content/directories');
  if (isnull(dirs)) dirs = make_list(cgi_dirs());
}
else dirs = make_list(cgi_dirs());


foreach dir (dirs)
{
  connector = string(dir, '/fckeditor/editor/filemanager/connectors/connector');

  # This URL won't trigger the DoS, but it will respond differently depending
  # on whether or not the software is patched
  url = string(
    connector, '?',
    'Command=CreateFolder&',
    'Type=File&',
    'CurrentFolder=/%00/&',
    'NewFolderName=', SCRIPT_NAME
  );

  res = http_send_recv3(method:"GET", item:url, port:port, exit_on_fail: 1);

  if (
    'Invalid current folder specified' >!< res[2] &&
    '<Connector command="CreateFolder" resourceType="File">' >< res[2] &&
    '<CurrentFolder path="/&#0;/"' >< res[2]
  )
  {
    vuln_urls = make_list(vuln_urls, url);
    if (!thorough_tests) break;
  }
}

if (max_index(vuln_urls) > 0)
{
  if (report_verbosity > 0)
  {
    report = string(
      "\n",
      "Nessus did not exploit this issue, but was able to detect it based\n",
      "on the response generated by requesting the following URL(s) :\n"
    );

    foreach url (vuln_urls)
      report += string("\n  ", build_url(port:port, qs:url), "\n");

    security_warning(port:port, extra:report);
  }
  else security_warning(port);

}
else exit(0, "No vulnerable installs were found.");