A popular Barcode Scanner App with above 10 million downloads on the Google Play Store has been caught infecting Android devices with malware.
The app has been removed from the Play Store, but it likely remains there on many of the infected devices.
Scanner Turns Evil
Users had the Barcode Scanner App installed on their devices for long periods. After an update during December, Barcode Scanner had gone from an innocent scanner to full-on malware!
Though Google has already pulled this app, from a cached Google Play webpage that the update occurred on December 4th, 2020.
The majority of free apps on Google Play include in-app advertising. This is done by including an ad SDK to the code of the app.
Ad SDKs can come from various third-party companies and provide a source of revenue for the app developer. Users get a free app, while the app developers and the ad SDK developers get paid.
In the case of Barcode Scanner, malicious code had been added that was not in previous versions of the app. The added code used heavy obfuscation to avoid detection.
To verify this is from the same app developer, it had been signed by the same digital certificate as previous clean versions.
“Because of its malign intent, we jumped past our original detection category of Adware straight to Trojan, with the detection of Android/Trojan.HiddenAds.AdQR”, the report stated.
Removed from Play, but not from the mobile device
Even though the app has been removed from the Play Store, it has not been removed from the affected mobile devices.
Thus, until users install a malware scanner like Malwarebytes for Android, or manually remove the app, it will continue to display ads.
Experts further point out that the behavior of the malware is opening the default web browser by itself, without user interaction. This is different from web redirects that occur while actively browsing the web.
Therefore if you need to save your phone from getting infected, you will have to manually remove the app else it would continue to display ads.
“It is frightening that with one update an app can turn malicious while going under the radar of Google Play Protect. It is baffling to me that an app developer with a popular app would turn it into malware,” says Nathan caller of Malwarebytes.