How does a virus work?



Essential virus information - how a virus works


Your guide to how a virus works to compromise your computers safety


The word “virus” is often used as a common term for all malicious programs, but technically a virus is a program or code that attaches itself to a legitimate, executable piece of software, and then reproduces itself when that program is run. Viruses spread by reproducing and inserting themselves into programs, documents, or e-mail attachments. They can be transmitted through e-mails or downloaded files and they can be present on CDs, DVDs, USB-drives and any other sort of digital media.


A virus normally requires an action to infect a victim. For instance, the malicious programs inside e-mail attachments usually only strike if you open them. The effect of a virus can be anything from a simple prank that pops up messages to the complete destruction of programs and data.



Viruses before and now

Almost one third of internet users in the European Union caught a PC virus despite the majority having security software installed, statistics show. Viruses were most prevalent in Bulgaria and Hungary, as a survey of 30 countries reveals.


The 2010 figures, released by the EU's statistics office to mark Internet Safety Day, show the safest countries were Austria and Ireland.


Viruses had their heyday around the year 2000, with the Y2K scare. In 1999, the Melissa virus caught antivirus companies flat-footed and propagated rapidly. It was the first real outbreak of many of its kind that spread using Microsoft's Word and Outlook. A year later, the 'I Love You' virus caught the world by surprise. Lloyds of London estimated that the virus cost the global economy $10 billion, making it the most expensive piece of malicious software to be unleashed to date. It was also the first time a computer virus became the day's top story for newspapers and television stations, marking a shift to mainstream awareness of computer viruses.



New Antivirus information - mobile threats

Nowadays, mobile operators are also starting to feel the pinch from viruses resulting from the increasing use of e-mails and Internet browsing on mobile phones. There has been a 46% increase in malware that targets smartphones, compared to the same period in 2009, an industry study showed.


But mobile viruses are around 20 years behind those plaguing computers. This translates into more than 2000 virus variants targeting mobiles and smartphones, compared to around 400,000 such threats targeting PCs. In June 2004, a security company released the details of a piece of mobile phone malware that used Bluetooth to spread to other Symbian Series 60-based mobiles. That is believed to be the first case of a self-replicating mobile-phone virus and since then there has been a consistent increase in mobile viruses.


To protect yourself against viruses, you should always keep your BullGuard software up-to-date and your operating system and applications patched.

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