Downandup/Conficker worm infects 9 million PCs

Judging from the complaints and questions filling my inbox, Windows security looks like it's already on track for its worst year this decade. The latest attack is a worm called Downandup, Downadup, Kido!, or Conficker (all the same thing), and it primarily seems to be being delivered via infected USB drives.

How's it work? By tricking you into running the virus by modifying the way "autorun" works when you plug in a drive. Look closely at the screenshot above and you'll see two entries for "Open folder to view files." The one at the top is a phony entry that actually installs the virus on your machine... but of course it's the default selection that pops up when you plug in a drive. Once installed, the virus spreads like crazy via a separate flaw in Windows networking system (now patched, so be sure to run Windows Update if you haven't lately) and can quickly infect a whole office. F-Secure has more analysis on the clever way it tricks you into installing the malware yourself.