Android devices are most vulnerable to security threats and knowing that fact the many app developers use a variety of tricks to launch malicious apps in Google Play. There are over dozens of apps which can bombard with a series of unwanted advertisements in an Android phone, even when the apps weren't being used.

Researchers from antivirus provider Bitdefender revealed all the details related to their recent findings on Tuesday, January 14 and mentioned that there are a total of 17 such apps with a combination of 550,000 installations.

Malicious apps in Play Store

As mentioned by the researchers, they noticed that the apps wait 48 hours before hiding inside the Android devices, hold off displaying ads for four hours, pops up the ads at random intervals and split their code into multiple files. The researchers also noted that these apps also include the codes that help to appear them in Play Store with legitimacy.

It should be noted that one of these apps was a racing simulator which also charged in-app fees for extra features in the game. The app also continuously displayed ads that drained batteries and sometimes prevented users from playing the game.

The researchers reveal that after four-hours, ad displays are generated by using a random three-digit number that was checked against a value. If the random number was equal to the value an ad would appear on the screen. Which means when a user unlocks an infected smartphone, there is a chance that the device will display an ad.

Malicious racing game
Bitdefender

Affected device

The ad-showing mechanisms are also divided into multiple activities and use modified adware developer kits. But the identification of the source became hard due to the randomness of the ad appearance as well as the display-time intervals and the app make the display unpredictable.

The report said, "Users see multiple ads either in-game when pressing different buttons or even if not in the app. The frequency at which ads appear while in the game depends on a random value. In half the cases, there is a probability that when using some game functionalities, an ad pop[s] up."

Apps which you should delete now

Bitdefender researchers found 17 such malicious apps which were downloaded a total of 550,000 times. At publication time, the tech giant Google was in the process of removing the apps from the Play Store. The apps are:

17 Google Play apps
17 Google Play apps Bitdefender