7 Of The Most Dangerous Computer Viruses Of All Time

Are you looking to defend against computer viruses, or bolster your overall network security for better cyber resilience and protection?

The answer’s probably “yes” – and even if it’s “no”, you may find that you change your mind after reading about how expensive the most dangerous computer viruses in history were to those affected by them.

Read on below to learn about the biggest threats that ever existed in the world of I.T. services and personal computers, starting with…

1. MyDoom (2004)

MyDoom was released in the early 00s; long before most users had a computer security system in the form of an antivirus or firewall. As a result, millions of Windows users became affected and 25% of all e-mails sent in 2004 contained the virus.

What truly made MyDoom lethal was that it allowed hackers to access infected computers, causing massive I.T. security issues. This made it one of the most dangerous computer viruses ever – and resulted in $38 billion in damages worldwide.

It might be tempting to write these losses off as a product of a time when there was little protection against I.T. security threats… But bear in mind that the next virus on our list, despite coming out even earlier, only did around half the damage!

2. ILOVEYOU (2000)

Despite its cute name, ILOVEYOU made technology news for all the wrong reasons. It infected around 500,000 computers in 2000, when the internet had far fewer users… And caused damages worth $15 billion, becoming one of the most expensive network security threats in history.

What made ILOVEYOU particularly dangerous was that it didn’t simply rely on technology to spread. Instead, it used basic psychology to persuade users to open an infected file.

Specifically, the virus would send itself to an infected users’ entire contact list via an attachment called “LOVE-LETTER-FOR-YOU”. A file like this from a trusted individual was enough for internet users to double-click immediately, resulting in the fast spread of ILOVEYOU.

Unfortunately, not everyone developed an I.T. security strategy after this experience – and I.T. news saw another major threat the very next year, in the form of…

3. Code Red (2001)

Discovered by an I.T. security consultant enjoying a Code Red Mountain Dew, this worm attacked Microsoft IIS web server installations.

With a tiny size of 3,569, it relied purely on Random Access Memory to spread and didn’t require much hard drive space, which allowed it to bypass most contemporary data security measures, and resulted in tens of thousands of servers crashing.

The scale of Code Red may have been somewhat smaller than those of the previous two entries. Nevertheless, this was one of the most dangerous computer viruses of the 00s because it affected web servers, which were expensive and difficult to fix back in 2001.

4. Stuxnet (2009-2010)

Stuxnet is one of the worst computer viruses in I.T. history. It’s almost completely unique in that it attacked real-life objects as opposed to virtual property.

Specifically, Stuxnet targeted Iran’s uranium enrichment equipment in Natanz, ostensibly causing most of Iran’s centrifuges to self-destruct.

This makes Stuxnet one of the most expensive I.T. security risks ever, and we can only hope that the hackers behind it don’t figure out a way to do the same to other physical objects in the future.

5. Conficker (2008)

With $9.1 billion in damages caused, Conficker is one of the most expensive computer viruses of the last decade. It’s also one of the most widespread and persistent – and the worst part is that unlike regular viruses, Conficker is a “trojan” that gives hackers remote access to infected computers.

Even though Conficker came out at a time when I.T. security products were widespread, and tech news let us know of the threat, up to 15 million computers were affected.

As the old saying goes, “defence is the best offence” – and with viruses like Conficker, the best thing you can do is have an I.T. security strategy that prevents infection in the first place.

6. Melissa (1999)

Melissa was the first virus that mailed itself to users’ contact lists. Since it came out at a time when information security standards were lax, and most people didn’t know how to protect from computer viruses, it spread quickly and easily.

The positive news is that, by computer virus standards, Melissa was fairly benign. It “only” resulted in 80 million dollars worth of damages, making it one of the less pricey cases in the history of computer viruses.

7. Zeus (2009)

Unlike past computer viruses, Zeus was so sophisticated it made infected Windows computers engage in criminal tasks.

It was also made with the express goal of generating a profit, and resulted in the criminals who made it getting up to $70 million dollars.

Large companies like Amazon, Oracle, Bank of America and others were affected, despite powerful security computer services, which shows you just how dangerous a virus could be in the past…

Even for companies equipped with the best information security services.

As you can see from the examples above, I.T. security compliance can’t be underestimated.

Even large conglomerates and advanced internet users can fall victim to a virus. Make sure to always stay up to date with regular I.T. security audits and refer to information security companies to prevent and reverse I.T. threats fast.

Do you want your network and devices to be safe from various online threats? For more information on IT security call 1300 530 609 today!

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