The .NET Browser Add-On Security Uproar

Some Firefox users are screaming bloody murder over a Windows update that quietly adds an unwanted browser extension to their systems. Maybe it's time to step back and take a deep breath.

Matthew McKenzie, Contributor

June 1, 2009

4 Min Read

Some Firefox users are screaming bloody murder over a Windows update that quietly adds an unwanted browser extension to their systems. Maybe it's time to step back and take a deep breath.Last February, Microsoft issued a service pack for its .NET Framework 3.5. Among many other things, the service pack installs a Firefox browser extension, dubbed Microsoft .NET Framework Assistant, that enables one-click installation of downloaded .NET applications.

The Firefox extension, which installs automatically, went largely unnoticed at the time. So did the fact that the extension's "uninstall" button in Firefox -- a feature users expect to get with every such add-on -- does not work.

Disabling the .NET Framework Assistant is a simple matter; the "disable" button still works just fine, and Firefox will not load disabled extensions. Users who want to remove the extension completely, however, must edit the Windows Registry manually.

Now The Trouble Starts?

Last week, the code finally hit the fan over the Microsoft update.

On Friday, Washington Post technology columnist Brian Krebs belatedly took Microsoft to the woodshed for releasing its no-knock Firefox extension. Other sites, including The Register, and Slashdot (picking up a article) also jumped on the dogpile.

This has got to be one of the strangest cases of a delayed-reaction freakout I have ever seen online. All of the current crop of articles dealing with this issue refer to an item first published on -- last February 27.

I'm not excusing Microsoft's actions. The company's decision to install its Firefox extension without permission and without an "uninstall" button shows extremely poor judgment.

One Microsoft employee justified this approach by noting that the company simply wanted to ensure that .NET "ClickOnce" functionality worked for every Firefox user (and thus every FF profile) on a Windows system, rather than working only for the user who actually installed the extension. It's a classic example of developers making technology choices that ignore the context within which users will view those choices.

And as Krebs pointed out, it's an approach that could lead users to question the wisdom of installing other software via Windows Update. That breach of faith could, in turn, expose users to far more serious security risks.

Finally, how many companies want to install a Firefox extension on an employee's desktop that allows them to install anything with "one click" simplicity? Large companies that scrutinize all of their updates carefully before rolling them out might catch this feature and decide whether or not to allow it. Smaller companies that rely upon Windows Update to install updates automatically don't have that luxury.

Mistake? Yes. Disaster? Not Even Close.

So Microsoft made a mistake. It's not the first, and it certainly isn't the worst. So let's call off the attack dogs and focus on what this particular incident really means, here and now.

-- The .NET Framework Assistant never installs a .NET app automatically. While "one click" software install support may not be an ideal software-security paradigm, it's not a life-or-death threat, either.

-- Claims that the .NET Framework Assistant conceals "spyware" or "malware" are silly and pointless.

-- Keep in mind that .NET apps are sandboxed using a security model not unlike the one that Java uses. While any new software creates risks that may affect both security and system reliability, it's important not to blow those risks completely out of proportion.

-- Last month, Microsoft issued an update to .NET Framework 3.5 SP1 that re-enables the "uninstall" button when a Firefox user views the extensions list. It is my understanding, however, that SP1 still installs the .NET Framework Assistant.

-- Even without the update, Windows users can still shut down the .NET Framework Assistant by viewing their list of Firefox extensions (click "Tools" and then "Add-Ons"), selecting the Microsoft extension, and clicking "disable."

-- Many Windows users (including yours truly) choose not to run the .NET Framework at all. Some companies do run at least a few key .NET applications, although many others do not. If your company does install any version of .NET, however, then it's a bad idea to skip service pack updates that often contain important security patches. Doing so could expose your systems to much bigger problems than just an unwanted Firefox browser extension.

It's easy to get wrapped up in the excitement when a bunch of Web sites jump on a hot news item like this. Just keep in mind that it may be more dangerous to over-react in such situations than it is not to react at all.

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