15 Shocking and Damaging Computer Viruses That Plagued The World

Hackers and the viruses they've created have now become cultural icons in their own right. The term 'hacking' was once used to describe criminal activities. Now it is becoming a popular verb. There are former hackers giving TEDx Talks available on YouTube, showing you basically how it's done and giving the public the knowledge to create new viruses and other types of malware.

The most popular and modern examples of hackers are of fun, young, billionaire entrepreneurs, along with cool, intimidating activist hackers. As a result, hackers have become more associated with pop culture and geopolitics, as opposed to shadowy criminals who live behind screens. The places they once occupied in the popular imagination have been taken over by the likes of Mark Zuckerberg, Julian Assange, and the group known as 'Anonymous.' It is easy to forget the heady days of the 1990s and early-2000s. During this time, computer viruses were being randomly and widely spread, affecting anyone with an email address.

Despite the cultural makeover, hackers are very different in 2017, even in the wake of cybersecurity firms increasing their efforts to fight malware and breaches.

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14 The 'Skulls.A' Virus

The 'Skulls.A Trojan' targeted mobile devices running on the SymbOS operating system.

Launched in 2004 the virus would breach a system via an innocuous-looking app download and shut down the phone's functions, except for the call function. In an added creepy touch, the virus replaced all the onscreen icons with a pixilated, early-Nintendo style skull and cross-bones. An anti-technology computer hacker. How ironic is that?

Pop culture is a powerful thing in the modern world. This is why celebrity endorsements work. This was likely the reasoning behind the 'Anna Kournikova' virus.

More of a practical joke along much the same lines as the 'Skulls.A Trojan,' the Anna Kournikova virus was launched in 2009. Playing on the celebrity culture of the day, the virus infected a computer following an attempt by the target to download, what they thought would be, sexy pictures of the popular tennis star. What they actually got was a worm infection.

While damages brought by the virus were minimal, the event had ripple effects through pop. culture. Even reaching out beyond the web, into the realm of traditional news media and episodic television comedy.

13 Sircam

A relatively new invention in terms of tech history, malware is now one of the most common types of computer viruses. One of the worst examples of malware was the Sircam attacks at the dawn of the new millennium.

For the greatest amount of damage, the virus attacked and infected random Microsoft Office files on the target's computer. Once installed in the system, the virus acted as a sort of chain letter from hell, sending itself to all the people on the victim's contact list. An analysis done by the University of Florida estimated the clean-up of the Sircam virus at $3 billion.

12 Melissa

One of the first mass-damage viruses of the modern computer age, the 'Melissa' virus was a self-propagating virus written in 1999. A brilliant piece of computer engineering, it would resend itself to the first 50 names in the Outlook address book of any user who opened it. Making sure that the virus would spread fast and wide before anyone could stop it.

The designer of the virus, David L. Smith was arrested by the F.B.I. Despite infecting 20% of the world's computers and doing $80 million worth of damage, Smith served just over a year and a half in prison and paid $5,000 in fines.

This was the same year that saw notorious hacker Kevin Mitnick sentenced to nearly 4 years in prison plus 3 years probation.

11 MyDoom

Though hackers can be cliché at times, it is still not clear what reasoning was behind the name of the MyDoom virus. Though there is no question about the damage it did.

Unleashed in 2004, the MyDoom virus spread like a brush fire in the summer. Not going after each computer but entire systems, the damage reached down to the core of net itself.

The worm doubled the average page loading time on a global scale. It also ran a shockingly successful denial of service campaign against Microsoft. Written to have a sense of self-preservation, the virus also made it impossible for infected computers to download anti-virus software to get rid of it.

10 Cryptolocker

Not all viruses are so random or system focused. Combining the 'IRL money-making tactics' of traditional kidnapping and classic “give me the money or else” extortion, the creators of the Cryptolocker virus had more of an old-school approach to cyber crime.

Created in 2014, Cryptolocker encrypts an infected computer's hard-drive holding the files for ransom. Taking full advantage of the new bitcoin digital currency, the hackers then demand up to $300 from the owner of the affected system. Those who pay the ransom are sent an encryption key to unlock their hard-drive. Those who cannot pay or refuse to bend to the hacker's demands have all of their files erased.

9 Zeus

Looks like the old joke about hacker egos might have a grain of truth to it. While not quite as cliché as setting one's password as “God”, naming your embezzlement virus after the Greek King of the Gods comes pretty close.

The Zeus virus was launched in 2009 and was widely thought of as a product of organized crime. While most malware infections lead to data loss and a headache, this program surpassed all expectations of modern malware infections. This sneaky virus, once inside a system, would use phishing and keylogging protocols to document online banking details and then empty the targeted account. Before it was shutdown, the program stole a total of $70 million from private bank accounts.

8 Sasser Worm

In April of 2004, Microsoft became aware of a weak point in the Windows Local Security Authority Subsystem Service (LSASS). Recognizing this as a hack waiting to happen, the company released a 'patch' to re-enforce Windows systems against any potential threat. They did not act fast enough, however. Before the patch could be fully used, a teenage computer hacker launched a worm designed to go after unpatched systems.

Aside from the financial damages, estimated at $18 billion, the worm was responsible for destroying several different company networks in the airline, hospital and transportation industries.

7 Conficker

It should come as little surprise that someone in the international hacking community figured out a way to go after anti-virus software. One of the most effective programs was the Conficker virus, also known as 'Downup,' 'Downadup' and 'Kido.'

While no one knows when it was first launched, it was first detected in late-2008 and was meant to disable any anti-virus software on affected computers, as well as automatic updates to those programs.

The spread was so fast and uncontrolled that the virus soon transcended domestic computer systems and attacked vital networks of the British, French and German armed forces. The overall damage estimated at $9 billion.

6 The Sobig.F Virus

In yet another example of the age-old advice, the Sobig.F Trojan malware virus did a lot of damage. Despite its stupid, distinctly juvenile moniker, this stealthy bit of bytes was one of the most effective and indestructible computer viruses ever.

Unleashed in 2003, back before anyone knew what Facebook was, the Sobig.F Trojan infected an estimated 2 million PCs worldwide. The overall impact was the grounding of all flights from Air Canada. It also caused severe slowdowns in internet servers worldwide.

The virus was so cleverly disguised, many targets didn't know it was a virus until it was too late. So ingrained was the code into the affected systems and wide-spread was damage that the cost of the clean up ran up to $37.1 billion. One of the most expensive and extensive malware cleanups in history.

5 Storm Trojan

As computer networks get more common and complex, cyber-security has tried to protect them. Though dark side hackers have also put increased effort into breaching them.

Unleashed upon an unsuspecting world at the beginning of 2007, this one piece of email distributed malware, was one of the most successful virus attacks of the internet age. It created a massive botnet of up to 10 million computers by the time it finally destroyed. Designed to change its code very 10 minutes, the virus was almost untraceable.

It was so well designed and distributed that it made up 8% of all computer infections. In three days. The architect of this code of mass destruction was never caught and remains unknown to this day.

4 The ILOVEYOU Virus

This modern virus was launched when the authorities couldn't tell a webserver from a serving tray. The 'ILOVEYOU' worm was so clever it was almost mad. Launched in May of 2000, the creator was trying to make up for the let down of the Y2K anti-climax, by wreaking own sort of cyber Armageddon on the world.

Exploiting the sort of human oddness that makes secret admirers seem endearing and not creepy, the 'ILOVEYOU' worm disguised itself as an anonymous love letter. It spread so fast, infecting 10% of the world's computers. It was one of the most destructive viruses in history, causing estimated damages to the tune of $15 billion.

3 Nimda

Causing the sort of damage that angry, high-school Anarchists can only dream about, the Nimda worm attack came from someone with a genius IQ and a serious problem with authority. Launched, in the most militant sense, days after the September 11th attacks, conspiracy theorist believed the virus had been a plot by Al Qaeda. Whoever it was that wrote the code was never caught. It targeted institutions as opposed to spreading randomly among people on privately owned networks. Spreading through multiple vectors, it infected several viral systems including banks and federal courts. The bill for scrubbing all the systems affected was $500 million.

2 Code Red

In one of the few examples of a virus named not by its creator, the Code Red worm was first launched in July of 2001, allegedly by hackers working for the Chinese government. Eventually discovered and diffused by Marc Maiffret and Ryan Permeh, they named it after the flavor of Mountain Dew they were drinking at the time.

The worm spread quickly, infecting an estimated one-third of Microsoft ISS web servers on the day of its release. That comes out to about 359,000 servers in 24 hours. It even breached security at the White House, and the official site was replaced with message boasting: “Hacked by Chinese!” The cost of the damages associated with the virus ran into the billions globally and the hackers who designed it were never identified.

1 SQL Slammer/Sapphire

The 'Slammer/Sapphire' is a little-known virus with an awkward name, and shows that size does not matter.

Composed of a scant 376 bytes of data, the SQL Slammer/Sapphire virus was launched in late January of 2003. 'The little virus that could' caused worldwide damage a decade ago. Effects include slowing 9/11 call centers, disabling up to 12,000 Bank of America ATMs and knocking the majority of South Korea offline. Most disturbing this is that the virus crashed the safety network at the Davis-Besse Nuclear power plant in Oak Harbor, Ohio.

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