Understanding what port scanning is and how the technique has been utilized by an eBay contractor
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. Let’s dive into the controversy and explain what is going on here.
First off, I need to talk about port scanning technologies to set the context. A great place to get started learning about this issue is this blog post from Avast’s Answers site. Briefly, every Internet application uses a particular network port number to do its business. So-called “well known” ports include 80 for web traffic, 22 for secure shell, and 143 for IMAP-based email communications. A complete list can be found here. If you use a traffic analyzer (also called a sniffer), you can view these communications and get an idea of what applications run on your network.
There are two ways to do these scans. The first and by far most popular method is where someone initiates a scan remotely across an entire IP address range or domain. There are many tools that can do this, one that I have liked for decades is from Steve Gibson called
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