With new security updates from vendors like Adobe, Apple and Java coming out on a near-monthly basis, keeping your Web browser patched against the latest threats can be an arduous, worrisome chore. But a new browser plug-in from security firm Qualys makes it quick and painless to identify and patch outdated browser components.

The Qualys BrowserCheck plug-in works across multiple browsers — including Internet Explorer, Firefox, Chrome and Opera, on multiple operating systems. Install the plug-in, restart the browser, click the blue “Scan Now” button, and the results should let you know if there are any security or stability updates available for your installed plug-ins (a list of the plug-ins and add-ons that this program can check is available here). Clicking the blue “Fix It” button next to each action item listed fetches the appropriate installer from the vendor’s site and prompts you to download and install it. Re-scan as needed until the browser plug-ins are up to date.

Secunia has long had a very similar capability built into its free Personal Software Inspector program, but I realize not everyone wants to install a new program + Windows service to stay abreast of the latest patches (Secunia also offers a Web-based scan, but it requires Java, a plug-in that I have urged users to ditch if possible). The nice thing about Qualys’ plug-in approach is that it works not only on Windows, but also on Mac and Linux machines. On Windows 64-bit systems, only the 32-bit version of Internet Explorer is supported, and the plug-in thankfully nudges IE6 and IE7 users to upgrade to at least IE8.

Having the latest browser updates in one, easy-to-manage page is nice, but remember that the installers you download may by default come with additional programs bundled by the various plug-in makers. For example, when I updated Adobe’s Shockwave player on my test machine, the option to install  Registry Mechanic was pre-checked. The same thing happened when I went to update my Foxit Reader plug-in, which wanted to set Ask.com as my default search provider, set ask.com as my home page, and have the Foxit toolbar added.

This past week, I was reminded of a conversation I had with an ethical hacker I met at the annual Defcon security conference in Las Vegas a couple of years back who showed me what remains the shortest, most elegant and reliable trick I’ve seen to crash the Internet Explorer 6 Web browser.

If you’re curious and have IE6 lying around, type or cut and paste the following into the address bar (that last character is a zero):

ms-its:%F0:

or just click this link with IE6.

Here’s a short video example of the crash that results from typing that text above into an IE6 window:

The “ms-its” bit is a reference to one of the helper extensions built into IE6. Alex Holden, the Wisconsin based researcher who showed me this crash, said the bug is the result of a pointer overflow in IE. The crash does not appear to work in newer versions of IE.

Holden said he notified Microsoft about his finding back in 2004. An e-mail thread Holden shared with krebsonsecurity.com indicates that Microsoft engineers believed there were no severe security consequences of this bug, and that it would probably be fixed in a future service pack. Obviously, it never was.

One way XP users might encounter this would be if the short code above or something like it were included in a link sent to a targeted user via instant message or e-mail. Indeed, one could imagine a computer worm that went around and changed the victim’s default home page to this short bit of code. The victim would be no longer be to get online….with IE6, anyway (although a registry hack could almost certainly fix the swapped home page).

There is one interesting possible use for this tiny snippet of crash-inducing code. Maybe someone you know and care about insists on using IE6 or refuses to upgrade to IE7 or IE8. Install Firefox or some other browser alternative, and then change their IE home page to “ms-its:%F0:” Chances are good they will never be able to open IE6 again.