Again since the article doesn't mention which app was malicious it's hard to say but when I looked up the wallpaper apps developed by "jackeey,wallpaper" I see the apps requiring the following permissions:

android.permission.ACCESS_COARSE_LOCATION

android.permission.ACCESS_NETWORK_STATE

android.permission.INTERNET

android.permission.READ_PHONE_STATE

android.permission.SET_WALLPAPER

android.permission.WRITE_EXTERNAL_STORAGE

It seems strange for a wallpaper app to require internet access.