Malware coders have adapted two Android trojans to cope with Marshmallow’s new user permission model, showing that despite Google’s best efforts, crooks will plow through all the company’s security measures and still reach their targets, even if in lesser numbers.
Google launched Marshmallow last year. One of the key security features introduced with the mobile operating system was the new permission model that allowed apps to require the necessary permissions at runtime when a certain app function needed access to more data.
Initially, malware coders didn’t like this because it spread out all their malicious app’s intrusive permissions across different popups, giving users the opportunity to spot something wrong.
Crooks initially ignored the new permissions model
But crooks are resilient, so they adapted to adding the “target_sdk” attribute to the malicious app’s code, and giving it a value of less than 23. This value told Marshmallow to ask for all permissions at installation, like on older Android OS versions.
While this was fine and dandy in the beginning, security vendors quickly noted this change, and took a closer look at Marshmallow apps that employed this trick, and by doing so, brought the malicious apps more into the limelight.
Now,that two malware families, the dangerous banking trojan, and the Android.Cepsohord click-fraud bot, have evolved to use the new permission model, which they despised in the beginning. Both ask users at runtime for permissions, as they need them.
Furthermore, both trojan also checks at runtime if the permissions are still active. If the user has decided to revoke one or more permissions, the trojan asks for them again.
It’s all the same for malware coders
A possible explanation for why malware coders decided to take this road resides in the profile of infected victims. Most people that suffer from such virus infections aren’t technically trained experts, educated and experienced enough to spot such threats.
The vast majority are regular users, which often just click through all permissions without reading them. We’re all guilty of that, but some people just don’t care about permissions anymore, and that’s the reason why Google decided to split them across different screens.
Malware coders are leveraging on popup fatigue to help their malicious apps get all the permissions it needs. In case the user reads permission popups, he would have detected the suspicious malware regardless. In case the user just ignores the popups, the user gets infected anyway. So it’s practically the same for malware coders, who at the end of the day will be successful at infecting the same less-technically skilled and uneducated users as before, regardless if they ask for permissions in one way or another.
Sure, Android Marshmallow’s new user permission system is great and may help users spot abusive and privacy intrusive apps, but it only works if you know what all those popups and permissions do, and some people don’t, and that’s why Android malware is so successful right now.
It will take some time before the vast majority of users get truly acquainted with Android and how mobile malware works, but even today, after decades of having Windows around, users still get infected with malware.