If you’re an iPhone user who’s downloaded iOS 11, you’ll want to pay attention to this recent Tweet from F-Secure’s head of hardware security Andrea Barisani:
PSA: iOS 11 new control center WiFi and Bluetooth toggles don’t actually turn off their respective radios.
— Andrea Barisani (@AndreaBarisani) September 20, 2017
iOS 11 comes with a new Control Center that opens when you swipe up from the bottom of the screen. But ironically, the app seems to be lacking some control. When you tap the Bluetooth and Wifi icons, while the phone disconnects from any current Bluetooth or Wifi connections, it doesn’t turn off those features completely.
That means new Bluetooth or Wifi connections can still be made. In order to make sure those features are off completely, you’ll need to go into the separate Settings app and turn them off there.
From a security and privacy perspective, it’s important to understand this distinction because turning off Bluetooth and Wifi when you’re not using them prevents your device from broadcasting information about itself. And as Barisani noted to Motherboard, it also reduces your exposure to potential attacks via those vectors.
Here’s a video from a YouTuber demonstrating the way these icons work:
This issue is deliberate by Apple, as it wants users to be able to be able to continue using Apple accessories or features like AirDrop, AirPlay, Apple Pencil, Apple Watch, and others without interruption. Here is Apple’s documentation on the subject.
Our security advisor, Sean Sullivan, notes that while the Control Center doesn’t allow you to turn these features off, you can use it to check if they’ve been turned off or not – just look for the slash.
Bottom line? The Wifi and Bluetooth icons on the Control Center allow you to disconnect, not turn off. To accomplish the latter, you’ll have to use Settings.
P.S. Sullivan also notes that since he updated to iOS 11, when he uses his Fitbit, the associated iOS app often thinks Bluetooth is off even when it’s actually “on.” So expect future app updates as app makers scramble to address Apple’s changes.