There are at least 17 Trojan apps disguised as games available on the Google Play store, according to digital security firm Avast.
The apps are part of the HiddenAds family, a Trojan disguised as a safe and useful application that instead serves intrusive ads outside the app.
Avast previously identified and reported 47 of these gaming apps to Google, which have been downloaded over 15 million times collectively.
The firm explained that these apps are able to hide their icon on an infected device and then display device-wide intrusive ads. The ads will continue being served even after the app is removed.
"Campaigns like HiddenAds may slip into the Play Store through obfuscating their true purpose or slowly introducing malicious features once already downloaded by users," said Avast threat analyst Jakub Vávra.
"It's difficult to prevent adware campaigns since actors use one-off developer accounts for each app. While Google has been a great partner to remove malicious apps, users need to remain vigilant as they download new apps on their devices and check for telltale signs of a bad app such as negative reviews, extensive device permission requests and more."