Despite Google’s efforts to keep the Play Store safe, cybercriminals keep sneaking malicious software onto the official Android app store. In September, security researchers found 172 malicious Android apps on the Play Store with a combined total of more than 335 million installations, a new report by ESET researcher Lukas Stefanko shows.

48 apps that were classified as adware accounted for over 300 million installations, while 15 apps with a total of 20 million installations involved subscription scams and 57 apps with over 14 million installations contained hidden ads.

Read more: New Google Android Warning As Malicious Apps Hit 300 Million Play Store Users