Spam email volume is increasing across the globe, in part due to the rise of spam-sending botnets, or networks of malware-infected computers that are remotely controlled, according to a Cisco report.
The Cisco 2017 Annual Cybersecurity Report presents research on attacker behavior, defender behavior and security professionals' perceptions of the industry.
Here are four things to know.
- Almost two-thirds (65 percent) of total email volume is made up of spam. In the United States, 2,046,000 emails were blocked by spam-detecting technology between December 2015 and November 2016. In 2015, there were only 1,351,000 connection blocks.
- The spam volume seen in 2016 is almost as high as the "record-high levels" detected in 2010, according to the report. This volume had been decreasing in recent years, due to antispam technologies; however, new botnets have reversed this trend.
- Between 8 percent and 10 percent of spam throughout the globe in 2016 could be classified as "malicious," according to the report. In October 2016 alone, 75 percent of spam sent malicious attachments.
- As malicious spam email attachments increase, Cisco notes that cybercriminals are also "experimenting with a wide range of file types." The Necurs botnet, for example, sends attachments in .zip formats that execute files in JavaScript, .hta, .wsf and VBScript.
Click here to view more of the report's findings.