Just two botnets, out of many in circulation, accounted for 97 percent of all spam emails sent in the last three months of 2017, according to a McAfee report released earlier today.
For all three months, Necurs spent its time spreading messages containing erotic websites and infecting computers with ransomware. In total, almost two-thirds of the spam messages sent in the last quarter of 2017 originated from this botnet's infrastructure.
Second on the list of botnets is Gamut, which was also built on Windows computers infected with malware to send spam emails. Gamut – which was smaller in size compared to Necurs – was more active in the summer of 2017, sending more spam than Necurs. However, in the last quarter of 2017, it decreased, with the botnet accounting for 37% of all spam messages, compared to 60% for Necurs. Most of the themes of Gamut’s deceptive messages were related to job offers and the movement of stolen money.
For 2018 the company reports the following:
- The number of malicious programs increased by 35%
- The total number of malware detections increased by 35%
- The Waboot malware was the most detected threat in the last months of 2017.
- Mac malware increased by 24% in Q4 2017 and 243% for the year as a whole.
- Flashback (Infostealer) and Longage (RAT) were the most prevalent threats for Mac.
- Java-based malware increased by 9%.
- PowerShell malware more than tripled, growing by 267%
