Google pulled over 20 malicious apps from the Android Marketplace today. The inevitable has happened. 2011 has become the year of mobile malware. All the pieces of the malware ecosystem puzzle that researchers have been warning about are falling into place:
The malicious apps that were pulled were legitimate apps that were pirated, modified by the attackers, and republished. To downloaders of these apps they behaved and looked like well-functioning apps. There was no reason for these users to rate these apps poorly in the Android Marketplace’s reputation system or to leave comments that the apps were suspicious. This shows that reputation systems are a poor method of ensuring an app store is free of malware.
To Google’s credit they did remove the apps and have, or will, wipe the apps from users’ devices but this is too little, too late. The mobile devices are already compromised as the malware took advantage of kernel vulnerabilities to root the devices and download more malware that didn’t come through the app store. Anyone who ran the malicious apps now has a compromised device running software with root permissions that Google cannot wipe.
The exact same thing could happen tomorrow even though we know what Android kernel exploit code was used and there are new versions of Android that fix these issues. This is because many Android phones cannot be updated to the new versions of Android, 2.2.2 and 2.3, that fix the root holes. Many Android phone providers have customized their versions of Android so up to half of Android phones running 2.0, 2.1, 2.2 are sitting ducks to the same problem tomorrow.
There are 2 problems that need fixing because we can’t fix the attacker motivation piece of the puzzle:
A viable mobile malware ecosystem has been proven today. 50,000 to 200,000 devices could be under the control of one attacker to do his bidding. His malware was downloaded that often over a 4 day period. In the biggest malware ecosystem, the Windows PC, a botnet of 50,000 to 200,000 devices is considered an attacker success. As sales of mobile devices overtake those of PCs we should not let an even bigger malware ecosystem thrive on this new platform. The time is ripe to clamp down on this out of control environment.