Caradoc: a pragmatic approach to PDF parsing and validation

PDF has become a de facto standard for exchanging electronic documents, for visualization as well as for printing. However, it has also become a common delivery channel for malware, and previous work has highlighted features that lead to security issues. In our work, we focus on the structure of the format, independently from specific features. By methodically testing PDF readers against hand-crafted files, we show that the interpretation of PDF files at the structural level may cause some form of denial of service, or be ambiguous and lead to rendering inconsistencies among readers. We then propose a pragmatic solution by restricting the syntax to avoid common errors, and propose a formal grammar for it. We explain how data consistency can be validated at a finer-grained level using a dedicated type checker. Finally, we assess this approach on a set of real-world files and show that our proposals are realistic.

Published in:
2016 Ieee Symposium On Security And Privacy Workshops (Spw 2016), 126-139
Presented at:
37th IEEE Symposium on Security and Privacy (SP), San Jose, CA, MAY 22-26, 2016
New York, Ieee

 Record created 2017-02-17, last modified 2018-03-17

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