"Cyber criminals are primarily using it to take over victim computers and conduct click fraud," McNamee continued. "With ZeroAccess, they can mimic the human behavior of clicking online ads, resulting in millions of dollars of fraud."

Kindsight estimates that online advertisers lose $900,000 a day in fraud perpetrated by ZeroAccess.

Spam, add-click malware, banking Trojans, theft of identity information, and fake security software are big money makers for cybercriminals, the report noted.

The cyber-security vendor also reported that it saw a 165% increase in the number of Android malware samples during the period. Nevertheless, despite the growth in spyware apps and malware, there have been no major malware outbreaks, the report said.