How concerned should we be about USB security?

Question

I had an ISP tech come by and set up service at my house, and I needed to access my router over Ethernet. My laptop doesn't have an Ethernet port, so I borrowed his Ethernet/USB dongle, I got everything set up and called it a day.But I've started getting a little concerned about using this untrusted dongle on my laptop, especially from a internet service tech who may or may not be plugging his dongle into all manner of devices around town.How concerned should I be about this? Should I trash my laptop and any accessories I've plugged into it since? This device is my central point of failure, I log into my banking accounts, admin accounts, it's my journaling medium -- you get the idea.

pwg · Accepted Answer

Unless you are being targeted as a North Korean spy by the likes of the NSA, that dongle is likely nothing more than an ethernet to USB translator chip with nothing nefarious going on anywhere.
> Should I trash my laptop and any accessories I've plugged into it since?
Only likely to empty your bank-account of the funds necessary for new items.

JohnFen · Answer

It's good practice to avoid plugging anything you don't trust into a USB port (whether it's a memory stick or not -- even just a plain cable presents a potential risk). But in your case, I agree with slater. You're probably fine, but maybe do a scan of your machine and keep an eye on things for a while.

austin-cheney · Answer

Extremely concerned. The military has outlawed USB storage devices for over 20 years.Personally I still use USB storage devices in limited contexts, like a source of music in my car or for installing a new OS.

slater · Answer

I'd say keep an eye on your network traffic, but no need to trash your laptop just yet.