Anytime you hear the word “virus” in conjunction with your computer, you automatically cringe. You never know what the damage will be or how difficult the virus will be to remove. Not every computer virus is considered to be a real threat. However, these next ten computer viruses will definitely make you want to add extra security to your computer.
LoveLetter
For such as sweet name, this virus packed a nasty punch. LoveLetter was a worm first introduced in 2000. LoveLetter targeted users through email, chat clients and peer to peer networks. The worm attacked addresses in Microsoft Outlook and sent a malicious executable within an email titled ILOVEYOU. LoveLetter overwrote file types such as .jpg and .gif, modified registry keys and moved other files. LoveLetter caused over $5.5 billion in damages to computer users.
Melissa
Melissa is another nasty virus that attacked computers in 1999. The first fifty names of a users Outlook contact list were sent an infected Word document. This virus ran rampant on corporate networks causing approximately $1 billion in damages. Melissa inserted Simpons’s quotes into documents and corrupted or deleted Windows system files.
ChernobylVirus
Chernobyl first appeared in 1998. This was considered one of the worst virus types because it could remain undetected in your computer’s memory until the damage was done. A software vendor accidentally distributed the virus, which resulted in a mass infection. Users of early Windows operating systems were infected. Chernobyl infected every application and executable a user ran. The worst part of Chernobyl was the fact that once it reached its trigger date, it erased all files on the user’s hard drive and overwrote the system’s BIOS. Chernobyl was responsible for over $20 billion in damages.
Slammer was introduced in 2003. Over half a million servers were infected and South Korea was offline for over twelve hours. Slammer didn’t affect personal computers, but did wreak havoc with servers. Slammer overloaded servers and routers, causing outages. Within ten minutes, Slammer had already infected 75,000 computers.
MSBlast
After an announcement from Microsoft in 2003 about a possible vulnerability, MSBlast was launched to exploit it. This worm displayed a message on infected machines stating the computer would shut down in after a few minutes. Infected computers remained on the restart cycle until installing the patch. Hundreds of thousands of computers were infected and caused over $2 billion in damages.
MyDoom
First introduced in 2004, MyDoom spread itself through emails. One method of attacking email addresses was through a Mail Transaction Failed message. Once the email was opened, all contacts were sent infected emails. MyDoom caused the Internet’s overall performance to slow, with web site load times delayed by as much as fifty percent.
Sasser
Unlike many of the viruses on this list, Sasser was not spread through email. The Remote Procedure Call vulnerability in Windows 2000 and Windows XP was Sasser’s target. This was the same vulnerability exploited by MSBlast. The two viruses were similar, with Sasser causing thousands of computers to shut down in just a few days. Sasser’s damage was must worse; however, with some Delta flights being cancelled, some satellite communications being shut off and numerous companies temporarily shutting down due to infection.
Sobig.F
Following on the heels of Blaster, or MSBlast, in 2003, Sobig.F caused Internet gateways and email servers to crash. This resulted in the slowing of the entire Internet. Sobig.F didn’t just infect Outlook contacts. Infected computers were searched for email addresses stored in various documents. Within a few hours, millions of copies of the virus had been sent to users. By the fall of 2003, the virus deactivated itself as it was programmed to do. During its run; however, almost $1 billion in damage was done.
Code Red was first introduced in 2001. Code Red attacked computers running IIS, or Internet Information Server. Infected computers received a message on their modified websites stating “Welcome to http://www.worm.com! Hacked by the Chinese!” After a short period, denial of service attacks were launched by the virus.
Conficker
Conficker was first introduced in 2009 and still hasn’t been stopped. Conficker allows its creators to install software on infected computers. This virus is used as a portal for cybercrime. Though Conficker doesn’t damage your computer, little is known about it other than the ability to steal personal information from your computer. Conficker is also used to send SPAM and lead users to online scams. This is perhaps one of the most dangerous on the list since the remotely installed software could be used to do almost anything to infected computers.
Prevent most viruses from ever reaching your computer by installing anti-virus software. If you ever notice your anti-virus software running slow or not running at all, save all open files and immediately run a full system scan with your computer in Safe Mode. This will prevent the spread of the virus while the scan runs. You may need to use a friend or family member’s computer to download removal instructions and patches.
No one wants a computer virus. The above list shows some of the most common and worst problems caused by viruses. Most viruses are variations on the ones listed above. Always stay safe. Don’t download files illegally, never open emails from anyone you don’t know and never visit suspicious sites in order to keep your system as safe as possible.
