According to the Microsoft Security Intelligence Report volume 14, computers are 5.5 times more likely to be infected with malware without an antivirus software.

The study finds that 2.5 out of 10 computers on average do not use up-to-date Antivirus; and shows that without this protection layer, computers are 5.5 times more likely to be infected with malware.

Some of the reasons why computers are unprotected – A trial period has expired or the software is out of date.The Antivirus was disabled by malware. People may not realize the importance of Antivirus so they do not install it.

Tim Rains (Director, Trustworthy Computing, Microsoft): Surfing the Internet without up-to-date Antivirus is like leaving your front door open to criminals. 

Microsoft detected and removed malicious email attachments from almost 3 million computers in the fourth quarter of 2012. People encounter this type of threat when opening documents, such as a PDF or Word document, that have been maliciously crafted and sent to them in email.

Keygen, a threat family commonly bundled with malware, was detected almost 7 million times in the fourth quarter of 2012. People seeking free or discounted software, movies or games online increase the risk of encountering this type of threat.   

You can find a copy of the report at the Microsoft website here.  

[Image courtesy: Microsoft]