The recent hysteria surrounding swine flu has brought viruses into the public consciousness again. Most people forget about the damage that a computer virus can cause. We take a look at the 8 most costly computer viruses.

Businesses and government departments have all been affected by computer viruses wreaking havoc through systems that resulted in small and large corporations alike losing vast sums of money. Here are 8 viruses that will have your CEO and tech support team running to the hills

Nimda $370 million

The nimda virus was released on September 18th 2001. Media outlets speculated that due to the release date of the virus it was somehow linked to Al Qaeda, although this was proved to be unfounded. It is estimated that the Nimda virus caused $370 million dollars worth of damage. Despite the damage caused, the name of the virus indicates a lack of imagination – it’s just “Admin” backwards.

SirCam $460 million

The SirCam virus caused around $460 million worth of damage to businesses. The virus was included in an email attachment. The subject lines of the emails included, “I send you this file in order to have your advice”, “I hope you like the file that I send you”, “I hope you can help me with this file that I send”, “This is the file with the information you ask for”

Sasser virus $500 million

Sasser first started spreading on the 30th April 2004. This worm was named Sasser because it spreads by exploiting a buffer overflow in the component known as LSASS (Local Security Authority Subsystem Service) on the affected operating systems. Sasser went on to disable the British coastguards mapping system along with causing Delta Air Lines to cancel transatlantic flights.

Melissa Virus $1.2 billion

Melissa shut down Internet mail systems and caused approximately $1.2 billion dollars worth of damage. The virus is probably the most sleazy ever invented as creator, David L. Smith, named the virus after a stripper he met in Florida. Melissa was spread and was spread from the Usenet discussion group “alt.sex”.

Code Red Virus $2 billion

The code red worm attacked computers running Microsoft’s IIS web server. It was named code red because the discoverers of the virus, Marc Maiffret and Ryan Permeh, had been Pepsi’s Mountain Dew CodeRed over the weekend as they tracked the virus.

ILOVEYOU $15 billion

The ILOVEYOU virus hit computers in 2000. When a user opened up an email with the subject line “I LOVE YOU” there was a file attached called “LOVE-LETTER-FOR-YOU.TXT.vbs”. When that file was opened it would send a virus to user’s email list and appeard that it had actually been sent by the user. It is estimated the the ILOVEYOU virus cost around $15 billion in damages.

SoBig Virus $37.1

According to BusinessWeek, “SoBig proxy software acted like sleeper cells in a terror network” The BBC even reported that at one point the SoBig virus was the fastest growing virus of all time. It is estimated that SoBig caused around $37.1 billion worth of damage.

MyDoom Virus $38.5 billion

The MyDoom Virus as first sighted on January 26, 2004 and became the fastest-spreading e-mail worm ever eclipsing the previous record set by the SoBig virus. Security experts believe that the worm originated from a professional underground programmer in Russia. It’s estimated that the virus caused $38.5 billion worth of damage.