A Downloader Trojan that runs on Android devices. It is a modification of the Trojan Android.DownLoader.818.origin. It was detected on Google Play, distributed by the Quoac developer as a game.
When launched, the Trojan prompts the user to grant it access to the SD card of the device with the following message:
When the access is granted, Android.DownLoader.819.origin requests administrative privileges.
After the Trojan is assigned the device administrator, it hides its icon from the app list on the main screen. For that, it restricts the access to the activity that launches it.
Then Android.DownLoader.819.origin uses its own service to download the Addon.apk file from the server https://cdn.*****.us and writes it to the external repository (an SD card or available memory of the mobile device). The file is the adware Trojan Android.HiddenAds.728, but other files can be downloaded too, depending on server configuration.
After the download, Android.DownLoader.819.origin prompts the user to install it every 20 seconds with a standard system dialog:
The dialog keeps showing until the owner of the affected device agrees to install the application.
Android.DownLoader.819.origin also registers a broadcast receiver that launches a Trojan service upon the following system events:
- android.net.conn.CONNECTIVITY_CHANGE—Internet connection or disconnection.
- android.intent.action.BOOT_COMPLETED—operating system loading.