Upgrading to iOS 11? Beware of changes to the control of bluetooth and wifi!
Turning off your Bluetooth and Wi-Fi radios when you’re not using them is good security practice (not to mention good for your battery usage). When you consider Bluetooth’s known vulnerabilities, it’s especially important to make sure your Bluetooth and Wi-Fi settings are doing what you want them to. The iPhone’s newest operating system, however, makes it harder for users to control these settings.
On an iPhone, users might instinctively swipe up to open Control Center and toggle Wi-Fi and Bluetooth off from the quick settings. Each icon switches from blue to gray, leading a user to reasonably believe they have been turned off—in other words, fully disabled. In iOS 10, that was true. However, in iOS 11, the same setting change no longer actually turns Wi-Fi or Bluetooth “off.”
Instead, what actually happens in iOS 11 when you toggle your quick settings to “off” is that the phone will disconnect from Wi-Fi networks and some devices, but remain on for Apple services. Location Services is still enabled, Apple devices (like Apple Watch and Pencil) stay connected, and services such as Handoff and Instant Hotspot stay on. Apple’s UI fails to even attempt to communicate these exceptions to its users.
It gets even worse. When you toggle these settings in the Control Center to what is best described as”off-ish,” they don’t stay that way. The Wi-Fi will turn back full-on if you drive or walk to a new location. And both Wi-Fi and Bluetooth will turn back on at 5:00 AM. This is not clearly explained to users, nor left to them to choose, which makes security-aware users vulnerable as well.
The only way to turn off the Wi-Fi and Bluetooth radios is to enable Airplane Mode or navigate into Settings and go to the Wi-Fi and Bluetooth sections.