Among the top 10 domains hosting the majority of bot-infected computers are some major ISPs -- Telecom Italia, Brasil Telecom, and Verizon, according to a new report on second-quarter email threats from Commtouch Software Ltd.

An average of 10 million bot machines were active each day during Q2. The geographic location of bots was fairly evenly distributed among several countries, with Turkey at the top (11 percent), followed by Brazil (8.4 percent), and Russia (7.4 percent) in Q2. The U.S. dropped from 5 percent of all zombies in Q1 to 4.3 percent in Q2, according to the report, which found Italy, India, Germany, Poland, and Colombia, respectively, ahead of the U.S. as well.

ISP IP’s are regularly sending out the most bot-borne spam, according to the report. Telecom Italia had around 1.2 million bots in Q2, just behind Turkey-based ttnet.net.tr, which had the most bots, 1.8 million. Brasil Telecom had a bot count of nearly 650,000, while Verizon was at about 556,000, according to the report.

Meanwhile, the amount of spam in overall email traffic worldwide ranged from 64 percent to 94 percent during the second quarter, which comes out to an average of 77 percent of all email. Another trend: pharmaceutical spam made up 46 percent of all spam, followed by sexual enhancement (22 percent) and replicas (21 percent). Porn was only about 3 percent of all spam, with loans/mortgage at 2 percent.

— Kelly Jackson Higgins, Senior Editor, Dark Reading