Avoiding online ads can be fairly easily achieved by installing a tool such as AdBlockPlus, but it's a different matter when it comes to apps in mobile apps.
Security researchers at Doctor Web have discovered that a number of Android apps found in Google Play are plagued with aggressive ad modules.
Advertising is considered aggressive if it appears on top of other windows, interferes with the use of applications, and makes normal use of a smartphone or tablet difficult.
This particular breed of advertising module has been used by criminals to monetise free apps, and has been added to the Adware.MobiDash.2.origin category in the Dr. Web virus database.
The company warns that malicious activity is not unknown: "Similar to its predecessor, Adware.MobiDash.2.origin starts to perform its malicious activity not right after the installation but after a period of time. This time period is long enough for the user to forget about the potential source of annoying notifications and advertisements, so the malware stays on the device intact."
Dr Web estimates that Android apps that make use of Adware.MobiDash.2.origin advertising have been installed more than 2.5 million times.