Off-the-shelf exploit toolkits provided the fuel to launch a record number of attacks last year, according to Symantec.
The company's latest Internet Security Threat report documented that Symantec products successfully blocked 5.5 billion "malicious attacks" in 2011, a surge of 81 percent over the previous year, with the number of malware strains rising to more than 400 million.
It credited the spike to malware polymorphism, a technique that enables the rogue code to constantly evolve so to fool detection by anti-virus technology.
This type of malware can often be found in commercially available attack toolkits, such as BlackHole, which enable the delivery web-based assaults, known as drive-by downloads without the user knowing their machine has been compromised.
The kits typically sell in underground forums for anywhere from $40 to $4000.
But it wasn't just the lower-hanging fruit that the attackers went after last year. Attackers also sent more personalised malware, via malicious links or attachments in emails, in greater numbers.
These were more sophisticated in nature than other socially engineered malware, and targeted people in specific job functions, most commonly executives, senior managers and people who work in research and development. Roughly half of such attacks hit small businesses, the report found.
The positive news for security professionals was that spam fell last year. Unsolicited email made up 88.5 percent of all messages in 2010, but only 75.1 percent last year. The report attributed the dip to the shuttering of a number of botnets, namely Rustock.
But that doesn't mean the hawkers of pharmaceuticals and knock-off jewelry are giving up the game. They've found new fertile ground in places such as social networking sites, in which users -- by being tricked into clicking on a link within their news feed -- can spread the spammers' message for them.