Several Android applications have been recently removed from the Google Play store, following the claims of a security firm that they were containing adware. Most of them seem to be Russian apps: the most popular of the removed apps was a card game called Durak (“the Fool” in Russian) – this one had been installed over 5 million times, according to the store’s public statistics. Another infected apps were a Russian history application and an IQ test app, according to the antivirus software maker Avast.

The security experts representing the company explained that when you, for example, install the card game, it seems to be a completely normal and well working gaming app, just like all the rest. And this impression remained until the users rebooted their devices and waited for a few more days. Then they started to feel there was something wrong with their phones or tablets: in fact, sometimes they only discovered the true colors of the apps after a month.

The problem was the pop-up ads shown to people each time they unlocked their infected devices. The ads were warning them about a “problem” that needed to be solved by installing new software. If the users accepted “help”, they were re-directed to harmful threats on fake pages, including dubious app stores, applications that were trying to send premium SMS without their knowledge or collecting too much of private data while offering no additional value.

The most interesting fact was that sometimes users were directed to security applications on Google Play store. Those were undoubtedly harmless, but security providers clearly were unlikely to want to promote their apps via adware.

In the meantime, security experts point out that the very presence of adware-toting apps on the Google Play is quite surprising, because Android malware and adware was usually originating from the apps distributed via unofficial stores, rather than Google’s official app store.

It looks like the company has taken an immediate action and removed the apps identified as containing adware. However, no one can deny that Android’s popularity (there were over 1 billion active Android users last summer) will continue to make these smartphones and tablets, along with their official store, a target for scammers and hackers.