
cc licensed flickr photo shared by Enric Martinez
In the relatively short history of computers and Internet usage, there have been some seriously pervasive computer viruses which have disrupted the lives of companies, individuals, and government institutions. Antivirus companies invest millions each year in studying past viruses, adding new layers of protection based on this research. Computer viruses come in many different forms, causing different kinds of problems and different degrees of severity, depending on the virus and the length of time before it is removed from the operating system. Below are five of the worst offenders ever recorded.
The MyDoom Virus
It started ominously enough. You open a message in your inbox, and it reads, “andy; I’m just doing my job, nothing personal, sorry.” This virus was opened by thousands of people across the world, accessing address books and using the infected computer’s email host to send itself to thousands of others. It contained a worm which took control of infected computers, using search providers to look up more email addresses which were then affected by it. While unconfirmed, it has been speculated that the virus originated from Russia.
The SQL Slammer Virus
Referred to by some as the Sapphire virus, this virus caused over one billion dollars in total damage. It attacked Microsoft’s server software, affecting thousands of servers, quickly doubling the number of machines affected with each passing second.
The Storm Worm
This virus came in an email bearing the subject, “230 dead as storm batters Europe.” It was a trojan horse that contained huge amounts of malware, rendering many operating systems useless. The virus came enclosed as an attachment in the email, and each infected computer became part of a network of computers containing the virus, doing its damage very quickly. While the Storm Worm still exists, it is fairly easy for any antivirus software program to detect, saving further frustration.
The Sasser Virus
This is one of two viruses that were traced back to a teenage boy in Germany. The Sasser virus found its way onto people’s computers through their IP addresses, taking advantage of a security weakness in Windows XP.
The Netsky Virus
The Netsky virus, engineered by the same perpetrator responsible for the Sasser virus, was sent via email, having many different results similar to those of the Sasser virus. These two viruses were significant enough to warrant a $250,000 bounty from Microsoft as an incentive to help track down the person who wrote both of these programs. After his arrest, he was tried as a minor, receiving a suspension of his twenty-one month prison sentence.
All such viruses no longer pose a serious threat to current Internet users, but users should always be on the lookout for these types of problems. Avoidance is the best measure which can be taken, which is why it’s important to have antivirus software installed on your computer, keeping it up-to-date. Routine maintenance at a computer repair store, performed by a technician or an IT specialist, will help to keep your system running efficiently, without the threat of viruses.
Stephen Holyman is a network administrator and contributor at Best Computer Science Degrees, a site with information about getting an online computer science degree.



I agree; avoidance is definitely the first and most sensible line of protection. Internet users should be aware of the sites and files they are accessing, and always ask themselves: do I trust this source?
These viruses can not only cause harm to the privacy of data, but they are capable of ensuring that no information on your system in left untouched. They can cause havoc and if by mistake you have your banking details saved, then be assured that they will not be safe anymore with these viruses.