Thread by @jasonkneen

Installed the new NHS COVID-19 app on iPad and iPhone and have them in proximity and lots of messages popping up in the console logs of the iPhone, without it being in the foreground.

Turned off the BT on the iPad, and I get disconnect messages on the iPhone logs -- turned it back on and more messages coming in.

Killed the app on both devices

Everything stopped.

Typically force killing on iOS means backgrounding stops (does for iOS / iPadOS usually) but it should kick back in on a reboot...

After a while I get this (without the app being run)

So here's the COVID 19 app logs from iOS having run the app & rebooted the phone -- it's been background running for a while now, logs are clear as it’s doing nothing then I reboot the iPad which has had the app installed and run.

(apologise for fan noise)

Long story short and final bit on this — after a short time testing and reading logs it appears the COVID 19 app on iOS appears to be backgrounding & waking up for it’s 10s on notification of a nearby iOS device with the app installed.

1/2

- it sometimes “Attempts to get more 10s”

- it seems to stop completely if killed unless relaunched even if rebooted.

(I haven’t waited for a background fetch or push or silent push (or other method) to wake the app back up if explicitly killed which they may be doing.)

2/2

So from what I can tell on Android 10 device, iOS is picking up the device and responding to it being installed, bluetooth on and off.

https://twitter.com/anautumnperson/status/1257954387231678464?s=21

https://twitter.com/anautumnperson/status/1257954387231678464

I still think there's a reliability issue here with keeping the app alive in the bg and have a horrible feeling that a trick being used is to capture the closing of the app and send a local notification to tell the user to relaunch it (like Tile do).

It should -- testing on Android and it's working in the background and iOS is picking it up -- it also worked on Android after a reboot (Android 10)

https://twitter.com/anautumnperson/status/1257954387231678464?s=21

https://twitter.com/anautumnperson/status/1257954387231678464

So far in tests this morning:

- iOS and iPadOS apps running in background for over an hour
- turn on / off BT on iPads and iOS app responds
- install on Android and iOS app responds
- reboot Android and iOS app responds
- turn off BT on all but iOS and app goes to sleep

Now it's just a case of wondering what happens if or when iOS decides to kill the background process and / or not send events to the iOS app, and what happens next because it seemed to die overnight until relaunched this morning…

So, final conclusion on what I'm seeing in logs on iOS, iPadOS, Android is the app is running in the background on all devices when locked and screen is off.

All apps talk to each other when they come into range (whatever that is) and exchange messages -- that's what I'm seeing.

I’ll give it a rest now, source code will be available soon and we'll have more conclusive details but my tests are showing that the COVID-19 app does NOT need to be in the foreground of an unlocked device to connect to other devices running it.

Out.

Honestly loving the articles and high five posts and tweets by reverse engineering and hacking companies coming to the exact same conclusion on the COVID-19 app as I did last night using only a usb cable and console.app.

I’m officially chopped liver.

🤷🏻‍♂️

Should be on @talkRADIO tomorrow around 2pm to discuss this.

https://twitter.com/jasonkneen/status/1257790047715315718?s=21

https://twitter.com/jasonkneen/status/1257790047715315718