Android App Infects Millions of Devices With a Single Update

A popular Android app called Barcode Scanner was turned into malware through a software update and could have infected up to 10 million devices, Malwarebytes researchers report. 

Barcode Scanner has generated more than 10 million installs on the Google Play store. Late last year, researchers learned some people were seeing ads that opened the default browser without user interaction. These ads seemingly came from nowhere, and none of the users had recently downloaded any new applications. The apps they had installed came from Google Play.

Investigation traced the ads back to Barcode Scanner, a legitimate app that had been on Google Play for several years before it displayed malicious activity. Google has pulled the app from the store; however, researchers predict based on a cached Google Play webpage that the malicious update occurred on Dec. 4, 2020. With this update, Barcode Scanner's suspicious ad activity began.

Malwarebytes researchers say in the case of Barcode Scanner, malicious code had been added that wasn't in earlier versions of the app, and that this new code used heavy obfuscation to avoid detection. The team confirmed this version was signed by the same digital certificate as previous clean versions, indicating it came from the same app developer (LavaBird LTD).

It's important to note that removing an app from Google Play does not necessarily remove it from a device. Unless affected users manually remove the app, it will continue to display ads. 

Read the full Malwarebytes post for more details.