Earlier this week, an annoyingly persistent Joker scamware was discovered in six Android apps.

All six have now been removed from the Google Play Store, but you might want to check to see if they are installed on your phone. Otherwise, the apps may try to drive up your phone bill with fraudulent premium SMS charges.

The French-American security firm Pradeo, which discovered the problem, has a list of problem apps and their unique package names, as many apps may have identical or similar names.

The dirty half-dozen include:

Joker Malware infected two dozen camera, wallpaper, messaging, and scanning apps about a year ago. Eleven more infected apps were found this past July.

But no matter how many times Google removes these apps from Google Play, more seem to invade.

Joker not only secretly signs up for premium SMS services, but also steals contact lists and text message histories, possibly spreading among friends. While not the worst malware in the world, it poses considerable financial and privacy risks.

Google reserves the right to disable or remove Android apps from users' phones if the apps are found to be harmful, but it is not clear whether Google did so in this case. Users might see a notice that they should manually remove certain apps on their phone.

In any case, there is a simple solution to avoid infection, exploitation, and fraudulent premium SMS billing: install and run one of the best Android antivirus apps. Some of them do not cost much, but they will give you peace of mind.