Last month we reported how the spam rate had dropped below 50 percent of email traffic. Almost as if in response to this seemingly watershed moment, the spam rate went up slightly in July, just crossing the midpoint mark again with a percentage of 50.1. While this is the first time the spam rate have increased in more than a year, we still anticipate that the rate will continue its slow, downward trajectory in the months to come.
The Manufacturing and Wholesale industries both saw significant increases in targeted attack activity in July, where both industries were up eight percentage points from June. Enterprises with more than 2500 employees were the most commonly targeted organization size during the month.
The number of vulnerabilities disclosed was up as well in July. There were 579 vulnerabilities reported, in comparison to 526 in June. Of particular note were six zero-day vulnerabilities discovered during the month—the highest number seen in more than a year. Four of these zero-day vulnerabilities—three for Adobe Flash Player and one for Microsoft Windows— were discovered in the data cache of the Italian covert surveillance and espionage software company, Hacking Team, which suffered a data breach in early July.
There were 53.7 million new pieces of malware discovered in July. While down slightly from June, this is still well above the 40.3 million average seen over the last twelve months. Ransomware has also declined slightly this month, though there have been modest increases in the amount of crypto-ransomware seen in July. There was also a slight decrease in malware detected in email traffic during the month, though the Agriculture, Forestry, & Fishing industry remained on top of the list of sectors most likely to receive malicious emails.
In contrast, four mobile malware families were released onto the mobile malware landscape in July, the highest number seen in one month during 2015. The number of mobile malware variants also continues to trend upwards, where 42 Android malware variants were seen per family during July.