Email and peer-to-peer networks also rank as significant venues for malware attacks, which have increased slightly in the U.S. but declined in Europe, according to Panda Security.

The motivation behind the $7.68 billion deal is unclear, but Intel says it wants to integrate computer security into its hardware.

The malware spreads through removable drives even if AutoPlay is disabled, installs rootkit on the computer.

False 'Verified by Visa' and 'MasterCard SecureCode' pages harvest customers' personal data.