Free Wi-Fi is a perk you expect at many hotels these days. It's perfect for the frequent traveler because it means you can easily connect your laptop or tablet to the Internet, or avoid burning up your smartphone's cellular data plan.
You'd even expect it to be safer than the free Wi-Fi at a coffee shop or other public place. However, that's not really the case.
Security researchers are tracking a mysterious hacker nicknamed "Darkhotel" who is a pro at using hotel Wi-Fi to steal information. Usually, the attacks target high-profile executives, managers and other people in business and investment, but another part of the hacker's operation is a broad attack that looks for interesting information anywhere it can find it.
The really worrying part is that this hacker has been active for years and no one has come close to figuring out who it is. Researchers think from some of the digital traces left behind in the attacks that he or she might be Korean and have the support of some government.
Still, somehow the hacker seems to anticipate exactly where targets are going to be. Experts can't figure out that one either.