A new bug in 3.2.1? security issue?

Well, Got my my iPad a week ago and when I set it up i just transferred all my iPhone Apps on to it.

Over the weekend I've been testing to see which ones were worth keeping on the iPad.

Today I opened an App called "Darts" (I had downloaded and forgotten about on the phone).

When I selected new game, the App crashed/quit, Air Sharing HD opened and the Darts App copied itself into the Air Sharing's documents folder. Clicking on the icon opens the App package to reveal all the individual files. See pics


I thought that Apps were sandboxed to prevent this king of thing. (i.e with the PDF hack could someone hide malicious code inside an App submitted to the App store?