Most Dangerous Computer Viruses In History

Today we are going to look at five of the most costly computer viruses ever.  
Slow computer random shutdown, must be a virus. Most of us have probably experienced a computer virus in one form or another. However not all viruses are created equal most can be sorted with a quick cleanup and an update of your antivirus, others though can spread like wildfire cause billion of dollars worth of damage and even be compared to a weapon of mass destruction. 

On May 4th, 2000 the ILOVEYOU computer virus exploded onto the internet leaving behind in a trail of destruction crashed computers and deleted files causing around $10 billion of damage. The virus was created by two programmers from the Philippines. It worked its way onto unsuspecting people’s computers through an email with a subject line “I love you” and an attachment titled “love letter for you”, people who opened the email and attachment unlocked the virus onto their system which would proceed to overwrite all their files steal their passwords and automatically send copies of itself to the victim’s list of contact. Despite going into hiding the pair who created the virus were eventually tracked down and arrested however neither were ever charged thanks to insufficient evidence and a lack of Philippines law prohibiting the creation of computer malware. I love you is considered as one of the most aggressive computer virus ever created and is thought to have affected over 10 million of the world’s computer including those of governments and large corporations.


The infamous code red hacked by Chinese computer worm. This little number was discovered by two EI digital security employees who named it after the cans of code red flavor mountain dew that they were sipping on at the time. This devastating virus attacked at multiple angles racking up billions of dollar worth damages. The code red worm targeted computers with specifically with the Microsoft IIS web server installed, exploiting a small problem that would end up having huge consequences. Once the computer gets infected from code red worm it would duplicate itself hundreds of times until the majority of the computer’s system were eaten up. The worm would then proceed to launch a denial of service attack on several IP addresses which even led to the bug attacking the white house website. Code red also allows for back door access to the hosted server allowing for remote computer access. The virus seemed to chew through everything in its path peaking just six days after its launch when it was discovered to be hosted on over 359000 computers simultaneously. The only trace code red left behind was a message on affected web page that read simply “Hacked by Chinese”. A message that has become viral meme I its own right, it’s estimated that code red affected up to 30% of six million Microsoft IIS Servers at the time causing around $2 billion in lost productivity.



Sasser is another windows worm that first started hijacking computers in 2004. Sasser was created by a computer science student Sven Jackson when he was just 18 years old. Teenage Sven was also the mastermind who created the equally devastating netsky computer worm. The sasser worm infiltrated computers operating on windows XP and windows 2000, rapidly spreading from one computer to another the internet, thanks to an open port found in the system’s vulnerable buffer overflow. Sasser caused infected computers to crash and shut down without warning. Now for the average user that would be really annoying but seeing assassins spread to over a million computers the effects were significantly worse than just an annoyance. The computer worm affected important global infrastructure from airlines to hospitals taking the estimated damage costs skywards of $18 billions, despite putting out a patch the virus continued to spread due to many computers neglecting to update. Microsoft eventually offered a $250000 bounty for information leading to the creator which saw Sven being arrested on May 7th, 2004. Despite the sasser-worm’s insane financial cost Sven luckily tried as minor and received just a 21-month suspended sentence. 


Conficker also known as down up is a computer worm of unknown origin that made its first appearance in 2008. Since its discovery conficker has infected millions of computers around the world and continues to do so to this day. Conficker is often regarded as the most persistent computer virus of all time by infecting and essentially linking millions of computers. Conficker has built itself up to be a fully fledged botnet a black market supercomputer if you will, at its height conficker had its claws sunk into at least 10 million individual IP addresses and as it grew stronger. There were very few computers network in the world secure enough to withstand a targeted attack. The director of FBI cyber division said that the virus has the potential for damage equal to a weapon of mass destruction and yet conficker has only ever been used once to spread a rather minor strain of scareware intended to frighten unsuspecting users into downloading fake antivirus software not exactly what we were expecting. Despite the one incredibly tame conficker attack due to how widespread the virus was its still estimated to of course $9 billion worth of damages. Three Ukrainian men were apparently arrested in 2011 in relation to the creation of conficker. They lived in penthouse apartments drove blacked out Porsches and yet they all claimed to only earn $30000 a year, strong links were found on the men’s computer’s however it’s unknown whether or not they were ever charged. 

1.     MYDOOM 

A fitting name for this highly destructive computer virus, after emerging in 2004 mydoom is still one of the fastest spreading most costly computer worms of all time. The virus spreads by collecting email addresses from infected windows computers and sending itself to victim’s contact list via a malicious attachment; if the attachment was opened by the receiver the process would repeat itself indefinitely. The virus quickly roped millions into a powerful botnet that was capable of a range of denied service attacks. In mid 2004 Mydoom even managed to take down Google preventing users from making searches for almost an entire day and other popular search engines at the time were also affected including Yahoo. The virus’s creator is/are unknown however it’s widely believed that the person responsible was paid or forced to do so. In the virus text there is a message reading “Andy I’m just doing my job nothing personal sorry”. Why the creator remains anonymous probably has something to do with the $ 38.5 billion in damages the worm has caused. It’s not hard to see that he/she wants to stay well hidden. Mydoom once accounted for up to a quarter of all emails being sent worldwide and still generates around 1% of the total today.

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