Google has stepped in to remove several Android applications from the official Play Store following the disclosure that the apps in question were found to serve intrusive ads.
The findings were reported by the Czech cybersecurity firm Avast on Monday, which said the 21 malicious apps (list here) were downloaded nearly eight million times from Google's app marketplace.
The apps masqueraded as harmless gaming apps and came packed with HiddenAds malware, a notorious Trojan known for its capabilities to serve intrusive ads outside of the app. The group behind the operation relies on social media channels to lure users into downloading the apps.
Earlier this June, Avast discovered a similar HiddenAds campaign involving 47 gaming apps with over 15 million downloads that were leveraged to display device-wide intrusive ads.
"Developers of adware are increasingly using social media channels, like regular marketers would," Avast's Jakub Vávra said. "This time, users reported they were targeted with ads promoting the games on YouTube."
"In September, we saw adware spread via TikTok. The popularity of these social networks make them an attractive advertising platform, also for cybercriminals, to target a younger audience."
Once installed, the apps not only hide their icons to prevent deletion but also hide behind relevant-looking advertisements, making them hard to identify.
In addition, the apps also have the ability to draw over other apps to show timed ads that cannot be skipped, and in some cases, even open the browser to bombard users with ads.
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Although such apps can be uninstalled through the app manager features of the device, it puts the onus on the users to search for the exact app that's the source of the ads and remove them.
Google, for its part, has been actively trying to stop rogue Android apps from infiltrating the Google Play Store. It has leveraged Google Play Protect as a means to screen potentially harmful applications and also forged an "App Defense Alliance" last year in partnership with cybersecurity firms ESET, Lookout, and Zimperium to reduce the risk of app-based malware.
If anything, the latest news is another reason why users need to scrutinize the reviews, developer details, and the list of requested permissions before installing any app.