One version of the ransomware attack takes over the device and displays a message stating the user had been watching child pornography and that it now demands payment of a fine to use the device again. The second version of Android ransomware is a bit more sophisticated, as it encrypts files on the device's SD card and blocks phone use by continually displaying a similar message and demanding a fee to decrypt the blocked files.
"It's clear that we will continue to see growing numbers of Android ransomware attacks, as we literally tracked their growing complexity from month to month during Q2 of this year," said Lior Kohavi, CTO at CYREN.
"These attacks are growing at an alarming rate, allowing this form of extortion to impact more and more victims due to most people's consistently low level of concern for security while using their phones. And yet, ironically, our phones today play an integral role in day-to-day life - making this form of attack that much more successful for the bad guys. When it comes to mobile devices, users need to maintain the same level of security and awareness that they hold for their desktops," Kohavi added.
The report also highlights spam-related statistics for Q2 of 2014:
- Spam levels remained essentially unchanged at an average of 55 billion emails per day for the quarter, although June experienced a noticeable drop to the lowest level in five years.
- Pharmaceutical spam still leads the pack, accounting for 43% of all total spam. Job offers hold steady in second place, with 22% of total spam. The notable shift in topics is the sudden increase in "pump-and-dump" stock spam, accounting for 17% of all spam emails sent in the Q2.
- While Spain (8%), Argentina (8%), and the United States (6%) continued to be among the leading spam-producing countries this quarter, the surprise was Vietnam, which accounted for 7% of all spam. Germany rounded out the top five, producing 5% of all spam. Noticeably missing during Q2 was India.
- The Russian Federation led the zombie countries at 13.1%, following by India at 10.7%. Interestingly, this is the first time India has been deposed from the top spot in more than four years. Peru joined the list this quarter, while Spain fell off.