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Convert potentially dangerous PDFs to safe PDFs

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1–10 of 72 posts

Re: Convert potentially dangerous PDFs to safe PDFs

#4

I personally just upload them to google drive. It would be a serious pwn if they could somehow still do a compromise through google drive.

Do you have any specifics on what Drive does? Any examples of it fixing embedded virii? Or is this blind assumption?

Re: Convert potentially dangerous PDFs to safe PDFs

#5
post #4

I personally just upload them to google drive. It would be a serious pwn if they could somehow still do a compromise through google drive.

Do you have any specifics on what Drive does? Any examples of it fixing embedded virii? Or is this blind assumption?

I assume they mean "upload to drive and use the web based reader to view the PDF," not "upload to drive and download it again"

Re: Convert potentially dangerous PDFs to safe PDFs

#7

It's a neat program, but what's the use for JPGs and PNGs?

There are some neat detection bypass / compromise methods using various image formats, including PNG [0] and SVG [1]!

I imagine that folks like journalists could have that type of attack in their threat model, and EFF already do a lot of great stuff in this space :)

0. https://isc.sans.edu/diary/31998

1. https://www.cloudflare.com/cloudforce-one/research/svgs-the-...

Re: Convert potentially dangerous PDFs to safe PDFs

#8
Shameless self promotion: preview.ninja is a site I built that does this and supports 300+ file formats. I'm currently weekend coding version 2.0 which will support 500+ formats and allow direct data extraction in addition to safe viewing.

It is a passion project and will always be free because commercial CDR[1] solutions are insanely expensive and everyone should have access to the tools to compute securely.

1. https://en.wikipedia.org/wiki/Content_Disarm_%26_Reconstruct...

Re: Convert potentially dangerous PDFs to safe PDFs

#9
While useful it needs a big red warning to potential leakers. If they were personally served documents (such as via email, while logged in, etc) there really isn't much that can be done to ascertain the safety of leaking it. It's not even safe if there are two or more leakers and they "compare notes" to try and "clean" something for release.

https://en.wikipedia.org/wiki/Traitor_tracing#Watermarking

https://arxiv.org/abs/1111.3597

The watermark can even be contained in the wording itself (multiple versions of sentences, word choice etc stores the entropy). The only moderately safe thing to leak would be a pure text full paraphrasing of the material. But that wouldn't inspire much trust as a source.

Re: Convert potentially dangerous PDFs to safe PDFs

#10

I personally just upload them to google drive. It would be a serious pwn if they could somehow still do a compromise through google drive.

Does google drive apply any transformation over the PDF, or are you effectively loading the same document in your browser on the round trip?
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