Kaspersky Labs Mobile Malware Evolution (Part 5) will cover the development of threats targeting mobile platforms in 2011. In December 2011 alone we uncovered more new malicious programs targeting mobile devices than over the entire 2004-2010 period. SMS Trojans are still the dominant behavior among all detected mobile threats, making easy money for malicious users. Spyware is now causing a host of problems for mobile device users. Backdoors represent the second most prevalent behavior; the third most common mobile threat behavior is spyware.”]
Source: https://securelist.com/mobile-malware-evolution-part-5/36485/

