A pair of Android barcode reader apps that were downloaded more than 1 million times were found to contain ad fraud malware that tries to stay hidden by generating advertisements that instantly disappear from view.
The malware, detected as AndroidOS_HiddenAd.HRXJA, can operate in the background even when infected devices aren’t actively being used, and it attempts to confuse victims as to the source of the infection by disguising itself as other apps.
In a recent company blog post, Trend Micro mobile threats analyst Jessie Huang names the offending apps as “Barcode Reader” and “QR & Barcode Scanner.” (Trend Micro did not reveal the publisher names.) Huang notes that Google removed the apps from the Google Play Store upon being informed of the scam.
Trend Micro says that in the course of its research, it actually identified samples of 51 different apps that demonstrated the same adware behavior; however, Google had either already removed these other apps, or they were distributed through other online marketplaces or websites.
We recently saw two barcode reader apps in Google Play, together downloaded more than a million times, that started showing unusual behavior. This includes behavior that can be seen even when the user is not actively using the phones.