If you're an Android user who is seeing ads pop up after your phone calls, you need not assume this is some new feature you have to learn to live with. It's actually an ad fraud scam, and you can do something about it. Researchers have identified dozens of apps on the Google Play Store that are able to display ads on top of the Android phone interface, a scheme known as AfterCall. How ads are taking over Android callsThis scam originates with seemingly harmless utility apps downloaded from the Google Play Store, such as calendars, alarm clocks, and notepads. When installed, they request overlay permissions, which allow them to appear on top of other apps—and thus display ads over phone calls. These apps can detect when a call ends and will then launch full-screen ads wrapped in a fake call info screen. Since it looks like they are simply part of the call interface, users may be less likely to suspect that they are actually malicious. It's worth noting that overlay permissions can't be granted via a standard pop-up during the app installation process. They are a type of "special permission" that requires users to go into their system settings to enable. Android apps are supposed to request these permissions in context and give a clear reason for doing so. AfterCall scammers are using justifications like alarms not being able to go off or appear correctly without overlay permissions, though some apps will simply crash if users decline permissions.How to remove AfterCall adsBecause the ads appear out of context—after a phone call and with content unrelated to the utility app—it's harder for users to figure out what's causing them. The utility apps aren't obviously malicious and don't appear on recent app lists when ads are displayed, so it's not obvious that they are connected to the problem. If you are seeing ads pop up after phone calls on your Android, check for apps that have overlay permissions. Go to Settings > Apps > Special app access (this may be hidden behind a three-dot menu) and click on the permission type. Look for apps you don't recognize, or which shouldn't have "display on top" permissions, and uninstall them. You should regularly audit these permissions, and disable any that aren't essential. On the user side, these apps seem to be mostly an annoyance rather than outright malicious programs that are harvesting your sensitive data, though installing any program that requests unnecessary permissions can introduce significant risk. If nothing else, however, these apps do appear to waste brands' advertising dollars and could damage their reputation with users—but you probably just care about how to stop seeing them after your calls.