Android 12 Developer Preview 1 Changelog: Google Finally Restricts the Power of “adb backup”

And they possibly have a plan to remove this feature in the future.

Photo by Markus Spiske on Unsplash

A few months ago, I wrote a blog explaining the power of the command line

adb backup

Retrieve Data From Android Devices Without Rooting

To summarize, “adb backup” is an official way to leak private data in certain apps. I said “official” because it’s designed and allowed by Android’s creator and there are also other unofficial ways to do it such as rooting a device.

With the Android 12 preview release, Google has announced a strong restriction (even a permanent removal in the future) of this command. It says that:

To help protect private app data, Android 12 changes the default behavior of the adb backup command. For apps that target Android 12, when a user runs the adb backup command, app data is excluded from any other system data that is exported from the device.

The statement is pretty clear: app data could no longer be extracted using adb backupcommand. Let’s go check the change.

I have created a simple app which stores a token in a SharePreference :

val sp = getSharedPreferences("SharePreferenceApp", MODE_PRIVATE)
sp.edit {
    putString("token","132s1f4156ze41fae51a4f5ez1af51ze5f5a1ze5f")
}

Don’t forget to set android:allowBackup="true".

At first, I check the command with targetSdkVersion 30 to see whether it works. Indeed, with the command

adb backup com.example.backup

, I get the SharePreference file in both Debug/Release mode.

If you don’t know how to use adb backupcommand, feel free to refer to my previous blog.

Now, I change targetSdkVersion to "S" and compileSdkVersion to "android-S" and try the command again.