At least 60,000 Android apps carried adware in the last six months, according to the cybersecurity research group Bitdefender.

Adware is software that often accompanies a program a user purposely downloads, like an app, and is designed to make money for bad actors by running ads in the foreground or background of the smartphone on which the app is installed. Adware can bleed a smartphone battery as well as make it run hot.

The malicious apps were not listed on the official Google Play Store and were instead found on third-party app store websites discoverable via Google Search. The third-party apps mimicked real ones on the Play Stores like Netflix, YouTube/TikTok without ads, free VPNs, and fake security programs, among others. 

When a user opens a third-party website from a Google search, they are redirected to a random ad page disguised as a legitimate download for the app the user wanted, but it actually installs the adware onto the device. Once the app is open, it shows an error message and includes an option to uninstall, though regardless of whether the user hits uninstall or not, it will stay in the phone’s background.

The malware, which has reportedly been live since at least October 2022, would have likely stayed undetected without Bitdefender’s new app anomaly technology, the cybersecurity company says. 

Meanwhile, as ExtremeTech notes, 55% of the malware infected apps targeted American users specifically, while South Korea, Brazil, and Germany are also significantly represented in Bitdefender’s findings.