TruePolyglot

Truepolyglot is polyglot file generator project. This means that the generated file is composed of several file formats. The same file can be opened as a ZIP file and as a PDF file for example. The idea of this project comes from work of Ange Albertini, International Journal of Proof-of-Concept or Get The Fuck Out and Julia Wolf that explain how we can build a polyglot file.
Polyglot file can be fastidious to build, even more if you want to respect correctly file format. That's why I decided to build a tool to generate them.
My main motivation was the technical challenge.

Features and changelog

Description Version
Build a polyglot file valid as PDF and ZIP format and that can be opened with 7Zip and Windows Explorer POC
Add a stream object in PDF part POC
Polyglot file checked without warning with pdftocairo >= 1.0
Polyglot file checked without warning with caradoc >= 1.0
Rebuild PDF Xref Table >= 1.0
Stream object with correct length header value >= 1.0
Format "zippdf", file without offset after Zip data >= 1.1
Polyglot file keep original PDF version >= 1.1.1
Add "szippdf" format without offset before and after Zip data >= 1.2
Fix /Length stream object value and PDF offset for szippdf format >= 1.2.1
PDF object numbers reorder after insertion >= 1.3

Polyglot file compatibility

Software Formats status
Acrobat Reader pdfzip, zippdf OK
Acrobat Reader szippdf KO
Sumatra PDF pdfzip, zippdf, szippdf OK
Edge pdfzip, zippdf, szippdf OK
Firefox pdfzip, zippdf, szippdf OK
7zip pdfzip, zippdf OK with warning
7zip szippdf OK
Explorer Windows pdfzip, zippdf, szippdf OK
Info-ZIP (unzip) pdfzip, zippdf, szippdf OK
Evince pdfzip, zippdf, szippdf OK
pdftocairo -pdf pdfzip, zippdf, szippdf OK
caradoc stats pdfzip OK
java szippdf OK

Examples

PDF input file Zip input file Format Polyglot Comment
doc.pdf archive.zip pdfzip polyglot.pdf PDF/ZIP polyglot - 122 Ko
orwell_1984.pdf file-FILE5_32.zip pdfzip polyglot.pdf PDF/ZIP polyglot - 1.3 Mo
x86asm.pdf fasmw17304.zip pdfzip polyglot.pdf PDF/ZIP polyglot - 1.8 Mo
doc.pdf archive.zip zippdf polyglot.pdf PDF/ZIP polyglot - 112 Ko
electronics.pdf hello_world.jar szippdf polyglot.pdf PDF/JAR polyglot - 778 Ko
hexinator.pdf eicar.zip (scan virustotal.com) pdfzip polyglot.pdf (scan virustotal.com) PDF/ZIP polyglot with Eicar test in Zip - 2.9 Mo

Manual

usage: truepolyglot format [options] output-file

Generate a polyglot file.

Formats availables:
* pdfzip: Generate a file valid as PDF and ZIP. The format is closest to PDF.
* zippdf: Generate a file valid as ZIP and PDF. The format is closest to ZIP.
* szippdf: Generate a file valid as ZIP and PDF. The format is strictly a ZIP. Archive is modified.

positional arguments:
  {pdfzip,zippdf,szippdf}
                        Output polyglot format
  output_file           Output polyglot file path

optional arguments:
  -h, --help            show this help message and exit
  --pdffile PDFFILE     PDF input file
  --zipfile ZIPFILE     ZIP input file
  --verbose {none,error,info,debug}
                        Verbosity level  (default: debug)

TruePolyglot v1.3

Code

Project Git repository

Contact

On IRC Freenode my nickname is hackade or by mail at truepolyglot@hackade.org.