Wednesday, May 23, 2012

New Research Published on Mobile Malware

Researchers at NCSU have started the Android Malware Genome Project, which is designed to identify and classify known malware samples for study. The researchers' results were recently presented and published at the Proceedings of the 33rd IEEE Symposium on Security and Privacy in San Francisco, California. The paper, entitled Dissecting Android Malware: Characterization and Evolution (PDF link), analyzes the 1,200 samples collected between August, 2010 and October, 2011. The research analyzes the samples to attempt to determine how it is installed (infection vector), how it updates and its primary activities on the mobile device, as well as the sample's relation to other samples.

The research groups infection vectors into several categories. Far and away the largest infection vector is through repackaging and redistributing modified versions of legitimate applications. The second group is spying applications - that is, software for one person to watch another person's activities. Some malicious software purports to do something (which it may or may not), but installs malware in addition - these are so-called Trojan Horses.

There were also several primary types of activity that the samples performed. Many of the samples attempted to elevate privileges on the device by taking advantage of a flaw in the Android operating system. The goal with this action is to allow the application to have greater access to the functionality of the device. Nearly all of the samples attempted to connect the device to a larger group of compromised devices controlled by the malware authors - a so-called Botnet. Researchers found that another common activity was contacting premium services, such as SMS text messaging. Many of the malware samples also collected information, such as user accounts, text messages and phone numbers.

The researchers also looked at the evolution of the malware samples and families over time. Specifically they looked in depth at two malware families to illustrate the rest, DroidKungFu and AnServer Bot. These two malware families show that authors have incorporated many sophisticated features to help circumvent detection and frustrate researchers attempting to study the samples, among other things. And their analysis showed that mobile malware is rapidly maturing.

Some other interesting analysis was performed on the samples. The researchers ran all the collected samples against four mobile anti-virus packages Detection rates ranged from 20-80% effectiveness, with a big name A/V company firmly at the back of the pack. Unknown malware is likely much more successful than these results indicate, meaning anti-virus software really needs to catch up.

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