Android users are being warned about a number of popular apps that featured hidden code resulting in malicious pop-up ads. The apps were being sold through the Google Play store, with one of the apps being downloaded around 10 million times according to security company Avast.
The offending app – a card game called Durak – has now been blocked by Google. Avast say it first learned about the issue after an Android user conducted his own investigation into how his Nexus 5 device became infected. Pop-up messages telling the user that his phone was running slow appeared on his screen, advising him to download other software to solve the problem. A number of these apps were also found to be malicious.
The apps didn’t show pop-ups until over a week after installation. This led users to believe that the messages were nothing to do with the apps they had recently downloaded. Other malicious apps included a Russian language IQ test and education tool. Apps made by the same developer included video games, cookery tips and wedding planning advice, according to the BBC. These have also been blocked.