If you think leaving the Wi-Fi option on your phone while walking around town is harmless – think again
We all do it. We get up and head to work, the store, or the coffee shop without even touching the Wi-Fi icon on our phone. For most of us, it’s a matter of convenience—we want our phone to automatically connect to a known network as soon as we arrive at our destination. But according to PCWorld and a number of security experts, this convenience comes at a high price.
When you leave Wi-Fi on while you’re on the go, your phone isn’t sitting still. It’s actively “shouting” into the digital airwaves, searching for known networks, and that’s where the trouble begins.
Your phone is “giving away” where you’ve been (and who you are)
Even when you’re not connected to any network, your phone is constantly sending out signals called “Probe Requests.” It’s basically asking, “Is ‘Home_Net’ here? And ‘Work_Wi-Fi’? And ‘Coffee_Center’?”
These signals contain your device’s unique address (MAC address), and often the names of networks (SSIDs) you’ve connected to in the past. Hackers, as well as marketing agencies and retailers, can use these signals to track your movements around town, building a map of your habits and the locations you visit.
The Evil Twin Attack
This is one of the most insidious of these tricks. Hackers can set up a fake Wi-Fi hotspot that has the same name as a legitimate network that your phone automatically connects to (e.g. “Free_City_WiFi” or the name of a popular coffee shop chain).
Because your phone has been “told” to trust that name, it will automatically connect to the fake network. Once you’re connected, an attacker can intercept all of your traffic—passwords, emails, bank card details—in what’s technically called a Man-in-the-Middle attack.
Silent Battery Killers
In addition to security risks, constantly scanning networks is an unnecessary burden on your battery. Your phone wastes energy trying to establish communication with every router you pass, which significantly shortens the device’s autonomy throughout the day.
What can you do? (Expert Advice)
You don’t have to give up the Internet to be safe. Here are a few “golden rules” of digital hygiene:
Turn off Wi-Fi when leaving a safe zone: Make it a habit to turn off Wi-Fi as soon as you leave your home or office. Use mobile data (4G/5G) while you’re on the move because they’re much harder to intercept.
Forget old networks: Go into your phone’s settings and delete (“Forget”) networks you no longer use, especially open public networks that you connected to once five years ago.
Turn off “Auto-Join”: Set your phone to ask for permission before connecting to a new or open network.
Use a VPN: If you absolutely must use public Wi-Fi (e.g. at the airport), be sure to use a reliable VPN (Virtual Private Network) that will encrypt your data and make it unreadable to hackers.