Are you constantly seeing unwanted ads on your Android device? Does it freeze up or crash for no apparent reason? Chances are, it’s infected with adware. Aside from being a nuisance, adware can also install malicious scripts designed to steal a user’s private information.

Zscaler’s ThreatLabZ team recently uncovered 17 adware apps in Google Play. These are apps that run unwanted ads on your device and collect your data for marketing purposes. Unfortunately, these apps were downloaded around 120,000 times before Google was able to remove them.

Fifteen apps were recently removed from Google Play following a Sophos report that identified them to contain malicious adware code. These apps are designed to serve users with unwanted advertisements and collect marketing-type data about them. If you think you’re one of the 1.3 million users worldwide who downloaded at least one of these apps, here’s a quick guide to finding and uninstalling them.