Almost twenty million new malware threats were identified in 2010, according to research by IT lab AV-Test.
The number is more than fifty percent greater than those identified in 2009, and the trend shows an alarming increase in the prevalence of unique malware samples over the last ten years.
The virus hunting security company marked another milestone, logging the fifty millionth malware signature in its index last week.
The numbers seem high because they chart unique signatures, many of which are variants of the same exploit, with very minor adjustments made to the malicious code.
The new variant, as yet to be named, infects Windows system by way of a PDF file that targets a security flaw in Adobe Reader.
Attackers are continuing to focus on infecting systems via third-party applications, mainly flash plug-ins, Adobe and Java.
Exploits utilizing the ubiquitous PDF document now account for as much as 36% of malicious code distribution, and PDFs are the leading source for web-based attacks according to Symantec's Quarterly Global Threat Report.