Last month, the global spam rate reached the highest level recorded since March 2015. According to Symantec‘s monthly threat report, which collects data from the Global Intelligence Network (GIN), this increase was due to the emergence of malware that attempts to spread itself via email.

Spam Rate Rises in July

In July, the global rate of spam rose by 0.6 points to 54.9 percent. The mining sector suffered the highest rate of spam with 59.1 percent, an increase of 0.9 percent. The report also revealed that businesses with 1,001 to 1,500 employees suffered the highest rate of spam.

In addition, the rate of email malware also increased to 1 in every 359 emails in July, the highest rate of such activity Symantec had seen since December 2016.

Drop in Malware Variants

Despite overall rates rising, SecurityWeek pointed out that new malware variants actually decreased, dropping from 66.3 million to 58.7 million variants. Symantec reported that organizations with between 251 and 500 employees had the highest rate of malware present in their inboxes, with 1 in every 260 emails laden with malware. The industry with the highest malware rate was the agriculture, forestry and fishing sector, at 1 per 152 emails.

Despite the overall decrease in malware variants, Symantec’s Security Response blog warned that the “trend in malware being distributed through email seems to be catching on, with several infamous malware families recently adding functionality that allows them to spread via spam email.”

Phishing on the Rise

Businesses also saw an increase in phishing attacks during the month of July. The rate increased to 1 in 1,968 emails, which Symantec described as the highest it had observed in the past 12 months. While phishing was up across most industries, the mining sector suffered the highest rate: 1 in 1,263 emails.

Despite a slight dip in the number of web attacks blocked by Symantec — from 1,159,398 to 1,158,985 per day — July marked the fourth consecutive month of elevated web attack activity. These numbers should make the security community more vigilant in its efforts to limit the spread of spam and malware.