Free WiFi is available nearly everywhere these days, giving us the ability to work remotely in hotels, coffee shops, restaurants and public parks. It’s convenient and liberating, but potentially unsafe.
Connecting to a public network requires little authentication — at best you’ll be greeted by a captive portal and have to check a box agreeing to the terms of service (ToS), or ask an employee for the password. Anyone can connect to these networks, including cybercriminals.
Attackers can setup their own “free” WiFi network in an attempt to lure in unsuspecting users. All an attacker has to do is find a high-traffic location, near a hotel or restaurant perhaps, and set up his fake network with an attractive name like “Free Public WiFi” or “Hotel X WiFi.” By the time authorities or telecom employees could arrive with the equipment needed to locate the source of the signal, the attacker would be long gone, stolen user credentials in hand.
We’ll examine the various threats posed by public WiFi as well as some common tools used by attackers and what you can do to keep yourself safe.
Threat Models
Security professionals use the concept of “threat models” to identify the most likely attacker and what steps to take to protect yourself from him. When it comes to public WiFi, the most likely threat is a common hacker or scammer attempting to steal a user’s information for profit.
If you have a three-letter agency in your threat model, such as the NSA or MI5, you’ll have to take extraordinary steps to stay safe anywhere you go. Our threat model is much simpler: a hacker attempting to steal your information and use it for profit.
Attackers could be after personal details such as your name, address, financial information, social security or other identification numbers. You likely wouldn’t notice anything is wrong until it’s too late — like when you notice strange activity on your credit report, six months later.
There is also the potential for blackmail if an attacker finds compromising documents or images on your device. If you have file-sharing options turned on it can be incredibly easy for an attacker to load ransomware onto your device, encrypting your data and demanding a ransom to unlock it. This is yet another reason why creating a backup strategy is incredibly important — if ransomware infects your device, you can wipe the hard drive and start over again thanks to your backups.
Think of an attacker as a fisherman: if he casts a net wide enough he’s bound to catch something. He may not care what it is or who he catches, but he’ll keep it all and sort through it later to find a way to profit from it.
