Security researchers reportedly have found dozens of Android apps in the Google Play store serving ads to unsuspecting victims as part of a money-making scheme.

ESET researchers found 42 apps containing adware, which they say have been downloaded more than 8 million times since they first debuted in July 2018, Tech Crunch reported.

Earlier this year, Reuters reported that an independent study lead by an academic group in Spain has shown that what personal information can be collected by pre-installed programs on new Android mobile devices is expansive and faces little oversight.

The investigation by the public Universidad Carlos III de Madrid, IMDEA Networks Institute and Stony Brook University looked at apps pre-installed on Android devices from 2,748 users, spanning 1,742 unique devices from 214 vendors across 130 countries.

The study did not look at whether the EU’s General Data Protection Regulation laws would bring greater oversight to pre-installed apps on Android devices.

Though Alphabet Inc’s Google owns Android, its open source nature enables device makers to customize the operating system and package other apps with the operating system before delivering them to users.

The study found the setup posed a potential threat to users’ privacy and security because the pre-installed apps request access to data that similar apps distributed through Google’s Play app store cannot reach.

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