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PDF Exploits On the Rise
An anonymous reader writes "According to the TrustedSource Blog, malware authors increasingly target PDF files as an infection vector. Keep your browser plugins updated. From the article: 'The Portable Document Format (PDF) is one of the file formats of choice commonly used in today's enterprises, since it's widely deployed across different operating systems. But on a down-side this format has also known vulnerabilites which are exploited in the wild. Secure Computing's Anti-Malware Research Labs spotted a new and yet unknown exploit toolkit which exclusively targets Adobe's PDF format.'"
I'm sure Secure Computing has a product for that. :-/
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Most PDF files have nothing more than text, vector graphics, and images in "read-only" formats. They don't have fill-in-the-blank fields or load-a-codec-and-play-a-video, or active content.
Web browsers need a "simple PDF" plugin that will activate on PDFs. If the "simple PDF" plugin loads a file with content it can't display, it will display what it can and give the user an opportunity to load the file in a full-fledged PDF plugin or external viewer.
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Hmmmm. Maybe this is because they've crammed all kinds of interactive content into a Portable Document Format?
I mean seriously. I thought the idea of PDFs was "this is as simple as a printed copy, and looks the same."
No, it's just that for some people PDFs are a hammer and every single printed word on the tubes is a nail.
I have had plenty of times where I was turning in papers electronically or needed to transfer documents between computers where PDF came in quite useful. When I'm turning in a paper electronically, I have no idea what version of Office the professor has. Nor do I even have Office. PDFs are very useful in this case.
Also, it may not be as bloated as you perceive. Acrobot reader is slow as hell. Evince and KPDF, both on Linux, are noticeably faster for me. There are alternatives for Windows as well that are better than the "official" reader.
Use the Sumatra PDF Reader. It is a very lightweight reader. Since it doesn't have all the other useless bloat crap that Adobe's reader has, I'm sure it is a lot less vulnerable. It is also open source, so you don't have to rely on downloading an even more bloated version of Acrobat Reader to fix the exploits.
http://blog.kowalczyk.info/software/sumatrapdf/
I have this installed on all of the PCs here at the office. It has eliminated just about all of the issues i had with the adobe crapware.
Interestingly enough, I have gotten 3 PDFs in the past few days in my corporate email inviting me to various "seminars" on technology subjects. All were very well written and professional looking but for products I have never used and companies I had not heard of. They passed both my email server's scanning and the local virus scan on my company laptop, however since I have very rarely gotten PDFs in the past I am now very suspicious.
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As a university professor, I actively encourage my students to use PDF files if possible. OS X and Linux come with PDF output, and I'm sure there's a way to do it in Windows without paying Adobe.
I also specifically PROHIBIT MS Office 2007/2008 .docx, .pptx, .xlsx, .xlwx, etc. formats. I'm not paying for an "upgrade" that completely changes the UI and introduces a new format without providing any real benefit to me.
Yes, I accept OpenOffice.org documents (as well as .dvi, .ps, and the formats from iWork)
Wait, we're supposed to trust the findings from SCAM Research Labs?
Personally, I'm waiting to get a job at Secure Computing's Over-The-Counter Hardware Research Lab.
On the contrary, PDF is (originally) a subset of PS plus the ability to embed fonts into the document, apply some overall compression where sensible, and stitch everything together into one carrier.
And while it is true that the past knows about "PS bombs" which e.g. will render your printer useless cause its interpreter is stuck in a loop (after all, PS is a Turing-capable programming language opening all sorts of fun if your idea of fun are stack-oriented languages), the problem with current PDF exploits comes from the fact that this format gets increasingly overloaded.
I can see why one would love to see Javascript and embedding all kinds of multimedia stuff within PDF. Would bring PDF on par with Powerpoint with respect to animations etc. -- which wouldn't be the worst thing for me, cause I love doing slides with PDFtex and beamer, and Adobe of course would like to present their format as a vital alternative to those nasty office formats.
But it also adds complexity. Instead of a simple postscript renderer you end up with a gazillion of helper libraries, bringing in their very own bugs.
There are alternatives for Windows as well that are better than the "official" reader.
Specifically Sumatra PDF and Foxit Reader are alternative PDF readers for Windows.
They are both orders-of-magnitude faster than Adobe Acrobat. Part of the reason for this speed boost is that they don't implement the hundreds of plug-ins that Acrobat supports. But frankly for >99% of the PDFs you encounter, those additional plug-ins are not required. (In the rare case where a PDF needs one of those features, I guess you can load up Acrobat.)
In addition to a speed advantage, using an alternate PDF reader is probably more secure. Both because it is less well-known (fewer exploits tailored to it), and because they don't implement those hundreds of plug-ins (some of which enable certain kinds of code execution).
What if you use a PDF reader that's not made by Adobe?
You download the virus using flash.
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For Windows the best (and free/open source) tool I've found is PDFCreator. It installs a "printer" on your computer that outputs to PDF. Using PDFCreator, you can make a PDF in any application that allows you to print. Using some of the "advanced" features (not really advanced, but slightly more complex than Print->PDF), you can even combine multiple print-outs from different applications into a single PDF.
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When I used to use Windows, I found Acrobat to be the most intrusive software ever because of its auto-update. Pretty much every time you try to open a document it's in your face demanding you allow it to update itself and then it often requests a reboot (a reboot? For a PDF viewer??)
This seemed to happen every other week, even if appeased it by letting it do its thing. I suspect this update would be one possible attack vector.
Yet another case in which a "fuck off" key would be a useful addition to the Windows keyboard.
The biggest issue is overuse and inappropriate use of PDF.
The only reason to ever use PDF is if it is NECESSARY for your audience to print the document in question.
Way too often websites have PDFs that are the only alternative for information. If you want to look up a train time for example, once and once only, you almost always have to download a PDF -- why? Sure, give people the choice of doing that if they want to, but there's no reason to slow down the internet for one-off pieces of information.
With concerns about the environment (perceived real or theatrical, regardless), you'd think that firms would stop encouraging frivolous use of paper. With the extortionate cost of printer ink, you'd think that firms would also be cost-conscious.
Uploading a 2 or 3 page document to the web in a PDF format is a criminal waste of resources, it's also an irritation that I don't need. I do not (and will never) work in a corporation. I do not need Office or PDF format -- ever. It's slow, and it's crap to read online.
I can cheerfully live my entire life without it, and I sincerely wish retarded developers and content managers would stop forcing it on me.
Although I usually decry any MS Windows-only feature proposal for not supporting Linux, I feel it is appropriate in this case.
Rich And Stupid is not so bad as Working For Rich And Stupid.
Not disagreeing here but you might like to know there is a common habit of disabling the loading of all the plugins in adobe. I forget how it is best done, but a cheap trick is renaming the plugin directory.
Actually, that only works for documents that you can view/edit in Open Office. For general purpose use, you can always opt for PDFCreator. We use it at our clients' offices, and have excellent results.
1. Has a tendency to make your browser freeze up
2. Tries to infect some sort of TSR in Windows called Acrord32
3. Will frequently pop up a "checking for updates" dialog
4. Makes the fastest of computers slow to a crawl.
5. a super-jumpy scrolling interface
No wait, those aren't malware symptoms, that's just in Adobe's product. Next week we will discuss the incredible annoyances of the "java runtime environment" daily annoyances & clog-ups in "Add/Remove Programs". Do ANY software vendors know how annoying their software can be at times? Even Apple is guilty of forcing add-on installs you have no choice to get out of.
I'm sorry, but in that very brief article linked, I saw absolutely ZERO analysis concerning frequency.
YAY! There's an exploit and toolkit. The existence of which is, in some sense, a useful piece of prior information for establishing the probability that there MIGHT BE an increase in frequency in the future - but it's quite a leap to have a freakin' /. link to a corporate article that uses hyperbole in claiming that there is some State of Nature or State of Knowledge that points to .pdf attacks being "On the rise".
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