Extortion malware was on the rise late last year, according to a report from F-Secure.
The company's Threat Report found that the Koler & Slocker ransomware families, which first appeared in the first half of 2014, grew rapidly during the second half of the year. F-Secure observed 61 new ransomware families for Android and three from iOS. Third-party app sites for OS X were plagued with pirated apps that contained Wirelurker—the apps were downloaded to iOS devices connected via USB to infected machines.
Downadup, or Conficker, ranked as the top PC malware threat, accounting for 35 percent of infected machines. Kilim at 11 percent and Sality at 10 percent rounded out the top three. The study noted that the Mac “scene” is getting quite noisy, with 17 new variants of malware observed between July and the end of December last year.