If you depend on the information stored on your personal computer, you need to understand how computer viruses spread, and you should use anti-virus software to reduce the chance that a computer virus will infect your programs and files.

A computer virus is a program that makes copies of itself and infects files. Computer viruses can spread to other computers and files whenever infected files are exchanged. Often infected files come as email attachments, even from people you know. The email senders have no idea that they are passing…

Perhaps most frustrating, however, was that Sasser infection was very easy to prevent. The vulnerability which the attack exploited had been patched for months, and all users had to do was install the most recent security updates from Microsoft.
Sasser was a stark warning that has yet to be heard by many. Unpatched systems are still pervasive around the world, leaving…

4. Nimda

The reason for this speed was that Nimda used every trick in the book to spread itself. It used email, open network shares, IIS vulnerabilities and even web sites to spread. It hit pretty much every version of Windows available and appeared all over the place.

In the paranoid days after…

6. Storm

The huge botnet was also influential for its continued use of social engineering tactics. The malware disguised itself as everything from video files to greeting cards, and attacks were continuously refreshed to coincide with holidays and current news events.

While Storm has since been eclipsed by newer botnets, the name still brings…

8. Conficker

The premise was pretty simple: Conficker.C would spread to as many machines as possible throughout March. Each infected machine was given a huge list of domains, one of which would be contacted by 1 April.

The deadline made all the difference. Now, Conficker wasn’t just a simple malware infection, it was a ‘ticking time bomb’, and a looming menace that would unleash carnage. Or at least that’s what the story turned into…

The virus was developed for the Apple II system and was a boot sector virus that spread via floppy discs. Apparently Skrenta was a fan of pirated games and would swap them with his friends, sometimes with little messages added. After one too many of these infected discs, he devised a way to alter discs automatically and the Elk Cloner virus was invented.

It had little in…

The viruses below may not have been the most widespread or effective, although many of them were. Instead they are the ones that stick in the mind as being particularly notable. There are been so many over the years, and viruses will always be a part of computing now, but…

Beyond that, there are some simple, common sense procedures that everyone should use, whether at work or in the home computing environment. Never open a file whose origins are unknown. In a simpler day, that wisdom only applied to executable files, or files that did something. They have the suffixes .exe, .com and .bat and each can start a program on your computer. These viruses spread through games…

Once you have purchased an anti-virus program, use it to scan new programs before you execute or install…