[FD] PDFMate PDF Converter Pro 1.7.5.0 - Buffer Overflow Vulnerability

Document Title: =============== PDFMate PDF Converter Pro 1.7.5.0 - Buffer Overflow Vulnerability References (Source): ==================== http://ift.tt/2jJG0mc Release Date: ============= 2017-01-30 Vulnerability Laboratory ID (VL-ID): ==================================== 2029 Common Vulnerability Scoring System: ==================================== 5.9 Product & Service Introduction: =============================== PDFMate PDF Converter Professional is a comprehensive PDF conversion application. It can also be used as PDF splitter and PDF Merger. PDFMate PDF Converter is easy to use with simple and clear program interface. ( Copy of the Vendor Homepage: http://www.pdfmate.com/ ) Abstract Advisory Information: ============================== The vulnerability laboratory core research team discovered a local buffer overflow vulnerability in the PDFMate PDF Converter Professional v1.7.5.0 software. Vulnerability Disclosure Timeline: ================================== 2017-01-30: Public Disclosure (Vulnerability Laboratory) Discovery Status: ================= Published Affected Product(s): ==================== PDFMate Product: PDF Converter Pro & Free - Software 1.7.5.0 Exploitation Technique: ======================= Local Severity Level: =============== High Technical Details & Description: ================================ A local buffer overflow vulnerability has been discovered in the official PDFMate PDF Converter Professional v1.7.5.0 software. The local vulnerability allows local attackers to overwrite the registers to compromise the local software system process. The `Convert_Pro.dll` file in the `C:Program FilesAnvsoftPDFMate PDF Converter Professional` path is vulnerable to a local buffer overflow. In case of a `html` file convert the `convert_pro` dynamic link library is used to create the file in the last instance with the already set conditions. Local attackers with restricted system privileges are able to include large unicode strings to the html template files of the `htmltemplate` folder. Local attackers are finally able to exploit the process by an overwrite of the registers to gain higher system access privileges. The security risk of the vulnerability is estimated as high with a cvss (common vulnerability scoring system) count of 5.9. Exploitation of the vulnerability requires a low privilege or restricted system user account without user interaction. Successful exploitation of the vulnerability results in process manipulation or compromise of the affected computer system. Vulnerable Module(s): [+] Convert_Pro.dll Proof of Concept (PoC): ======================= The vulnerability can be exploited by local attackers without user interaction and with low system user account. For security demonstration or to reproduce the issue follow the provided information and steps below to continue. Manual steps to reproduce ... 1. Install the software 2. Move into the htmltemplate path 3. Modify the index.html main template file that is used to generate the html file of a pdf 4. Include a large unicode payload inside of the file header and save 5. Start the software (PDFMatePro.exe) 6. Add a random pdf file and choose at buttom the html function 7. Click the convert button 8. The software process crashs because of the processing the large unicode payload via Convert_Pro.dll 9. Successful reproduce of the local buffer overflow vulnerability! PoC: Exploitation #!/usr/bin/perl my $Buff = "x41" x 4141; open(MYFILE,'>>index.html'); print MYFILE $Buff; close(MYFILE); print "Replace Index Template File"; PoC: Vulnerable Source (Template File)