Security researcher Lukas Stefanko discovered the trojan in the Google play pretended to be QRecorder app that records phone calls.
Once the app launched it requests the user to provide Draw over other apps permission to make the app functioning properly, but the malware abuses it to take control on what to be displayed on the user screen.
By having the overlay permission, the malicious app can draw an overlay at the top of the legitimate application to steal sensitive information from the user.
How the Android Banking Trojan Works
Threat actors used Firebase messages to communicate with the infected devices, they pass commands to check whether the targeted app installed on the device or not.
According to Stefanko analysis if the targeted baking is installed it requests the user to activate accessibility service and by having this permission it automatically downloads, installs and open the payload without user consent.
Stefanko published a Video on how it abuses the accessibility services and overlays banking app.
Once the app installed it triggers the targeted apps and overlay legitimate app and ask for login credentials. The threat actors primarily targeted German, Polish and Czech banks. here is the list of banking apps targeted.
com.apps.callvoicerecorder DA926010056A75E7DA0DE1292B0FC7C2DCD727A7 gjfid.pziovmiq.eefff E2DB952DFC2BCC65450129CE3A2F0892EF7D3CFB
Common Tips to Catch Fake Android App
- Look at the publish date. A fake app will have a recent published date.
- Do a little research about the developer of the app you plan to install.
- Very important – read all app permissions carefully.
Common Defences On Mobile Threats
- Give careful consideration to the permission asked for by applications.
- Download applications from trusted sources.
- Stay up with the latest version.
- Encrypt your devices.