If you use Firefox, especially on windows, read this!
If you fail to take protective measures you could stumble across a webpage which toasts your system.
Geoff wrote me:
Not sure about Linux and OS X – assume the worst.
For now, consider using another browser. But if you have to use FireFox…
The CERT advisory suggests that you configure FireFox to generate a warning dialog whenever it encounters one of the URLs involved in the exploit.
To do this, start FireFox, enter the URL â€œabout:configâ€, scroll down, and for each of the following entries make sure it is set to “true”.
If it isnâ€™t, right-click the line and choose “Toggle”, which will set the value to “true”
This will at least give you a warning that Firefox is being asked to do something suspicious; you will have to judge for yourself whether it is nasty.