The Hidden Network Hazard
Ubuntu’s NetworkManager is designed to silently maintain your internet connection. If you manually join a “hidden” Wi-Fi network (a network that does not publicly broadcast its SSID or name), Ubuntu remembers those credentials. By default, the system will actively probe for and automatically attempt to reconnect to that hidden network whenever it is within range. While convenient for your home network, this is a severe privacy and security risk if you travel. Because the network is hidden, your Ubuntu laptop must constantly shout the name of that specific network into the void, asking “Are you there?”, which allows anyone listening with a packet sniffer to track your movements or spoof the network.
Disabling Auto-Connect for Hidden Wi-Fi
To secure your device’s radio emissions and stop Ubuntu from automatically probing for and reconnecting to hidden Wi-Fi networks, you must disable the auto-connect feature for those specific profiles.
Open the Settings application and navigate to the Wi-Fi tab on the left sidebar. Since the network is hidden, it might not appear in the immediate list of visible networks unless you are currently connected to it. Under “Known Networks” or by clicking the three vertical dots (More options) in the top right, find the specific profile for your hidden network. Click the gear icon (Settings) next to the hidden network’s name. In the new window that appears, navigate to the General tab. Locate the checkbox labeled Connect automatically with priority (or simply “Connect automatically”). Click the checkbox to uncheck it. Finally, click Apply (or Save) in the top right corner. You will now have to manually select and connect to this network from the hidden network prompt in the future.