Among botnets, Cutwail was most active during the quarter, recruiting more than a million new machines. Nearly half of all new botnet control servers were in the U.S.

The McAfee report also noted a dramatic increase in malware designed to attack mobile devices that run . The total number of identified threats to Android devices more than quadrupledin the first quarter, reaching 8,000. However, part of the bump came from improved detection, according to the report. Most mobile malware aimed at Android did not come from apps offered through the Google Play app marketplace.

The report also found that most mobile malware originated in and targeted China and Russia.

also continued to rise steadily. New malware for the Mac exploded in the second quarter of 2011, but this last quarter saw the most new cases since then with about 250.