Locky ransomware attacks Attack.Ransom have dramatically decreased during December 2016 , according to Check Point . Locky , which uses massive spam campaigns as a major distribution vector , only surfaced in 2016 but has rapidly become one of the most popular tools for cybercriminals , part of a growing trend for ransomware cyberattacks Attack.Ransom that encrypt data on the target machine and demand payment Attack.Ransom in return for decrypting it . In December , researchers recorded an 81 % drop in the average number of Locky infections per week , compared with the weekly averages of October and November causing it to drop out of the top 10 global malware families for the first time since June 2016 . Overall , they tracked an 8 % decrease in the number of recognized malware attacks on organizations in December , which could be attributed to a Christmas holiday slowdown . Research also revealed the most prevalent mobile malware during December 2016 , and once again attacks against Android devices significantly more common than iOS .