Mitigate Adobe Reader Vulnerabilities with Google Chrome PDF Viewer

Adobe Reader has a growing list of exploits and a current unpatched vulnerability. The crux of the problem is that PDF documents are not simply documents. PDFs can contain arbitrary code in the form of Javascript or Flash as Adobe Reader embeds a full Javascript runtime and a private Flash runtime environment. Javascript can be disabled via the options but the Flash engine cannot be disabled via the GUI.

An interesting development is that Google Chrome 6.x includes its own PDF rendering plugin. This plugin converts PDF to HTML5 and renders it with the webkit engine. It is very fast and a fundamentally different approach from Adobe Reader. Commodity attacks on Adobe Reader should not be effective on Chrome.

The Chrome Beta channel includes the Chrome PDF viewer plug-in but it is disabled by default. Go to the about:plugins page to enable it. You can also disable the Adobe Reader plug-in while you are at it.


Sandboxing Flash with Chrome

Perhaps the most brilliant feature of Google’s Chrome browser is that it installs itself without any admin rights required inside each user’s profile directory. The first important consequence of this is that Chrome can go viral inside of corporate departments officially standardized on IE6 because it doesn’t require any tech savvy to install Chrome outside of the protected “Program Files” directories. The second consequence is that, since the user always has full permissions to its install directories, Chrome can and does silently and continuously update itself.

The updating works extremely well. It happens quietly in the background. After an update has occurred, the next time Chrome is started it is the new version. Chrome does have security bugs, but it uses Integrity levels to sandbox itself and patches are continuously and silently rolled out which keeps the browser safe.


Recently Chrome started distributing its own private copy of Adobe Flash. That means that Google believe that Flash is necessary. Since Flash is necessary, Chrome will always have the latest version of Flash and it will be silently updated along with Chrome itself. For all other browsers, there is no automatic update process for Flash. The standard ActiveX installation process for IE is painful and failure prone. For this reason alone, Chrome distributing its own Flash is great but since Flash is also riddled with security problems, this is a huge win.

Adobe seems to be happy with this Google-love, especially since they are being flamed publically and repeatedly by Steve Jobs. It is interesting but I think what is really going on is that Google recognizes that if Flash doesn’t work right or you get a malware while using their Chrome, Google takes the blame.

Whatever the motivation, it is a win. I’m ready to let Chrome handle updating my Flash and stop wasting my time worrying about whether I have the current version and whether it is safe. In fact, I can’t think of a good reason to have Flash floating around on my system as a global service outside of its Chrome sandbox.

Adobe provides a tool to globally uninstall Flash which removes both the ActiveX and Netscape-compatible plug-in versions but leaves Chrome’s private Flash runtime untouched.


Fix Adobe’s broken PDF preview in x64 Windows

Adobe’s PDF previewer control doesn’t work correctly in x64 Windows because the Adobe Acrobat installer has a bug since June 2007. To be clear, the PDF preview handler works fine on x64 Windows but the Adobe Acrobat Reader setup program doesn’t install it correctly.

This affects previews in the Explorer shell and Outlook 2007/2010.


Fortunately, Leo Davidson has solved the problem and developed a little utility to fix the Adobe PDF preview control on x64 Windows.


Wow. This installer defect has been there for what, 2 1/2 years. Seriously Adobe, this is just sad. Please fix it and while you are at it, send a nice thank you to Leo for solving the issue.

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