Just 3 of the many reasons why I'm seriously considering to ship next NoScript versions with Forbid MacromediaÂ® FlashÂ®, Forbid MicrosoftÂ® Silverlightâ„¢ and Forbid other plugins checked by default in the Plugins options panel, like it already happens for Javaâ„¢:
- A Quicktime RTSP Response vulnerability is being actively exploited in the wild.
- Programming errors in Flash or Silverlight applets can be as exploitable as traditional XSS/CSRF, if not more, no matter if the plugin itself is vulnerable or not. If recent attack on RSnake failed, it's most likely because he had NoScript configured to block Flash even on his own site. Not impractical as it may sound: in facts, you can select Apply these restrictions to trusted sites as well and enable multimedia clips or applets individually, on the fly with a click on their placeholder -- that's exactly what I do, by the way.
- As Pasqual Meunier of CERIAS put it,
Fully functional PDF viewers are now about as safe and loyal (under your control) as your web browser with full scripting enabled. That may be good enough for some people, but clearly falls short for risk-averse industries.
I did it, in the end. NoScript now blocks all plugins by default on untrusted sites, and you can optionally extend this restrictions to trusted sites as well.