Hacker News Reader

The author explains in the article that they previously gave a presentation outlining various techniques to achieve a "schizophrenic" zip file. The blog post discusses an additional technique that was not present in their previous presentation.

Author here :)

Are you saying that parser discrepancy is a well known problem OR that this exact technical issue described (CD offset vs CD size used to derive CD location) is a well known problem?

If the prior, you are of course right — parser discrepancy and the existence of these kinds of "multiple personality" files isn't a new thing. I'm pretty sure this can be traced back to at least the '80 :)

However, if you mean the latter, I would appreciate a link if you can recall where you've seen it before / read about it — I can then add it to the article.

Ok, so how do you handle them? Do you take screenshots of your PDFs before you forward them? Other ideas?

You can forward the PDF itself, not the zip file.

I don't know much about the subject but I do know that PDF is an executable format, and I suppose it could use fingerprinting (based on e.g. screen size or resolution) to become schizophrenic (?)