Re: pdf files in upstream tarball and -doc package

[Jay Berkenbilt <ejb@ql.org>]

Alejandro Exojo <suy@badopi.org> wrote:

> El Viernes, 11 de Febrero de 2005 17:21, Jay Berkenbilt escribió:
>> That isn't to say that it is impossible to create a security hole
>> through a PDF file, but it's more comparable to html in that respect
>> than to PostScript.  In other words, you could include a malicious
>> link or put invalid PDF data that would exploit a security hole in a
>> specific PDF viewer, but you can't actually embed malicious code.
>
> Really?
>
> http://lists.kde.org/?l=kde-core-devel&m=110470798901386&w=2
>
> I'm a PDF ignorant, so maybe I misunderstood something.

This article points to the fact that you can create a link in a PDF
that opens an application.  This is the kind of thing I meant when I
said that a PDF could include a malicious link in the same way HTML
code could, though PDF can do it in a more generalized way.  Since you
could embed the application "rm -rf /" in a PDF, I'll have to back off
a bit on my original point, so thanks for the correction.

The difference here though is that you could create a postscript file
that would remove files just by having you load it in ghostscript,
whereas the user would have to actually select a link in this example,
but in some ways, this is splitting hairs.  It's certainly somewhat
more difficult to examine the target of the link in a PDF than in
HTML, but as the article you referenced points out, the viewer can
help with this.

Thanks for making this point in response to my message.  I don't want
my message to lull anyone into a false sense of security -- you and
Martin are correct that it would be possible to create a PDF that has
damaging code in it in that sense.  Sorry for the confusion.

-- 
Jay Berkenbilt <ejb@ql.org>