In these days the net is populated by blog posts about the .NET Framework Assistant plugin for Firefox, its disabling and the fact Firefox does not warn user when a plugin installs itself without explicit permission.
Well, this is a old problem at least for me, indeed I discovered it some time ago when my Firefox crashed (apparently) without reason, discovering after a couple of days that Microsoft Office 2003 plugin fought with Foxit Reader and Google update plugins.
The problem was that I never installed Office plugin!
Disabling Office plugin Firefox stopped to crash.
After that experience I decided to write a simple (very simple) extension that at every Firefox startup checks if there are new plugins installed.
Nothing so cool, only a quick and dirty solution implemented in a few of hours.
Waiting Mozilla implements a better solution than mine you can install PluginChecker.
If you expect to find PluginChecker innovative or the “I-can-live-without-it” extension you are on the wrong place, if you expect a not intrusive and simple solution to unattended plugins installation than you can take a look at it.
You can download PluginChecker from SourceForge.
Snippets code from my daily experience 
Firefox already alerts you when there are new addons installed on startup, I expect it will be extended to plugins too.
Though the dialog makes a bit hard to find the new ones since it displays the entire list (I have like 80, a good chunk of those are disabled, though). So a dedicated tab to display newly installed plugins/addons (just like the “updates”/”installation” tab) would be very nice.
Eventually Firefox will add support for updating plugins so I expect we will be able to disable/uninstall them too just like addons.
Comment by Dan — October 18, 2009 @ 5:49 pm
> Firefox already alerts you when there are new addons installed on startup, I expect it will be extended to plugins too.
Originally I would to overlay the extension dialog but I had not enough time.
Maybe I can modify PluginChecker in this direction.
> So a dedicated tab to display newly installed plugins/addons (just like the “updates”/”installation” tab) would be very nice.
Is sounds very cool
Comment by dafi — October 18, 2009 @ 5:54 pm
“Firefox already alerts you when there are new addons installed on startup”
Not when they’re snuck in (silent install) by external apps. I was never alerted when the .NET add-on was installed globally (all current and future Fx profiles), or when I installed the Google Photo Screensaver app and a Google Photo Screensaver add-on was added to Firefox also globally.
In both cases there was never a mention that add-ons would be be installed into my browser nor an option to opt out, and they didn’t show as newly installed add-ons in Firefox either.
I’ve downloaded your new extension and will be installing it in a few minutes.
Thanks a lot for writing.
Do you plan on putting it on AMO?
Comment by Ken Saunders — October 19, 2009 @ 1:07 am
> Do you plan on putting it on AMO?
Sure but actually it is very ugly, maybe a little UI restyle and a better integration on extension/plugin manager is necessary 😛
Also a better “algorithm” to hide the config file, a malicious plugin can add itself silently
thanks to appreciate my work 🙂
Comment by dafi — October 19, 2009 @ 5:40 am
Your extension adds Array.prototype.diff and .unique, which results in very tenacious tooltips. Could you change your code in a way that doesn’t need these methods on Array.prototype?
I’ve filed https://bugzilla.mozilla.org/show_bug.cgi?id=524661 to fix the Firefox side of that bug.
Comment by Markus Stange — October 27, 2009 @ 1:07 pm
You are right, the implementation was done a long time ago without considering a publication.
I want to rewrite it in a better way and without polluting the Array object
Comment by dafi — October 27, 2009 @ 2:00 pm