Every week brings more security news and this week is  about an interesting piece of Javascript that can run in your browser if you happen to use eBay under a particular set of circumstances. The code can scan your computer and send information back to a security vendor, which could be used to track your movements across the Internet.

You can read my column for the Avast blog where I explain what is port scanning, what information is being collected, why an eBay contractor is doing it — supposedly to reduce fraud — and how security researchers figured out what was going on.