An anonymous reader writes: The USG is a small, portable hardware USB firewall that isolates a potentially harmful device from your computer. It's designed to prevent malicious USB sticks and devices laden with malware from infecting your computer.
That's where the USG firewall comes in. You plug in one end to your computer, and you plug in a suspect USB device into the other. A simple hardware serial link that only accepts a very few select number of safe commands, which prevents the device from executing system commands or intercepting network traffic. That means the data can flow from the USB device but effectively blocks other USB exploits.
These kinds of attacks might be rare, compared to spam, ransomware, and other kinds of malware, but they can still do considerable damage.