The dirty digital dozen – 12 worst computer viruses in history

Ali Qamar Last updated: September 19, 2022 Read time: 16 minutes Disclosure

These 12 worst computer viruses have generated billions of dollars via stealth malicious activities.

Did you know the world’s first virus actually emerged more than three decades ago? Yes, apparently, the mother of all viruses, “Brain,” first surfaced online in 1986. Since then, many harmless or harmful malware have emerged and disappeared as cybersecurity people learned to cope with them. Nonetheless, a few of these are still the worst computer viruses in the history of computer security.

This article tells you about the top 12 devastating computer viruses to hit the digital arena. Furthermore, these viruses are all ranked according to the extent of financial damages they inflicted on the world. Hence, while they might not look so sophisticated, they undoubtedly proved to be the most successful viruses for cybercriminals.

The top 12 worst computer viruses in digital history

Below we give you the costs, reach, key facts, and other details surrounding each virus. Nonetheless, this is by no means an extensive list of all digital viruses. Instead, they’re just the worst known malicious programs known to exist so far.

Every day, we have about 127 million pieces of malware attacking the digital denizens. So the list is infinite for any practical purposes. Our top twelve are the very worst but are not representative at all.

Not all the viruses listed below may fall into the category of “viruses” (technically). Instead, we have used the words “virus” and “worm” interchangeably here. This list merely intends to let you know the most devastating malware that have incurred huge financial damages until now.

1. Mydoom (38 billion)

The Mydoom outbreak is the worst virus attack ever to happen. Its estimated damage went as high as 38 billion USD (which would be 52.2 USD in current terms after adjusting for inflation). It also went by the name of “Novarg.” It was a worm that found its way around the internet mass emails. As this worm was active, it was responsible for about a quarter of the world’s email traffic.

As Novarg arrived into a system, it would scan it for fresh addresses. Then it sent copies of itself to those addresses. It also linked the infected computer into a botnet whose purpose was to carry out DDoS (Distributed Denial of Service) attacks. These attacks managed to shut down a website, or a server, by overwhelming it with junk traffic.

The funny thing about Mydoom is that it’s still around. But, unfortunately, it’s behind about 1% of the world’s phishing emails. If 1% strikes you as a meager fraction of those activities, think about this: the phishing traffic is currently about 3.4 billion emails daily. So that one percent represents thousands of millions of emails. So even 16 years after it was at the center of the world, Mydoom still has a life of its own, infecting those devices with the worse protection possible and still producing 1.2 billion copies of itself every year.