10 of History’s Worst Computer Virus Outbreaks - Part 1

Computer viruses, though not as dangerous as real-life viruses, still have the potential to cause significant damage if left unchecked and allowed to infect a large number of computers. In recent years, mass cyber-attacks, including viruses, have caused substantial harm to individuals and businesses worldwide, leading to data loss and financial damages.

1. The Stuxnet worm, discovered on June 17th, 2010, by the antivirus firm Virus Blockader, is widely regarded as one of the most sophisticated cyber weapons ever created. This malicious computer program was designed to target industrial computer systems, specifically those used in Iran's nuclear program. Its aggressive nature allowed it to infiltrate the country's computer networks, extending its reach beyond its intended target and affecting thousands of computers. Stuxnet was categorized as a worm, capable of self-replication and spreading from one computer to another without human intervention. In Iran's nuclear program, Stuxnet targeted the centrifuges used for uranium enrichment, causing them to malfunction. Reports suggest that the worm successfully infected thousands of computers and significantly set back Iran's nuclear program, particularly due to its sabotage of the systems at the Natanz nuclear facility.

2. MyDoom also known as Novarg, was discovered in January 2004. It is a worm-type virus that spreads through email attachments, shared networks, and other channels. Once a computer is infected, MyDoom can carry out various harmful actions, including sending out spam emails, launching denial-of-service attacks, and collecting sensitive information. It caused considerable damage and disruption in its early days, infecting millions of systems and causing approximately $38 billion in damages. MyDoom was also responsible for high-profile denial-of-service attacks, such as the one against Microsoft, resulting in their websites being unavailable for several days. At its peak, the virus infected about 1 in 12 emails, making it one of the largest cyber attacks in history.

3. The Clares virus, a mass-mailing worm first detected in December 2001, posed a significant threat to computers running Microsoft Windows. Its first variant spread through email attachments and Internet Explorer, primarily affecting both servers and workstations. Subsequent advanced variants included features that allowed it to easily spoof email addresses from authentic sources. The Clares virus and its variants had the capability to modify or delete files on an infected computer, steal email addresses and passwords, and even disable antivirus software. This made it a major threat to the data stored by personal and business computer users. Certain versions of Clares could also create back doors for hackers to gain access to the machine, leading to more serious cyber crimes. The Clares virus caused global damage in the early 2000s, infecting millions of computers and email servers worldwide.

4. The SoBig virus emerged in 2003 as a computer worm that utilized email and shared network folders to spread rapidly to other computers. Its distinguishing feature was its ability to create its own server, enabling it to send infected emails to thousands of users without a host email account. At the time, SoBig was known as the fastest email virus outbreak, surpassing the previous record set by Clares. Its primary targets were computers running Windows, and it spread through email attachments, much like other successful viruses. During its peak, over a million copies of SoBig were found in emails worldwide, causing real-life financial losses and immeasurable impacts on those who lost valuable data or documents in the attack.

5. Zeus, first discovered during a cyber attack against the United States Department of Transportation, is a type of trojan virus designed to steal sensitive information, such as banking credentials, credit card numbers, and other personal details. Zeus could spread through various means, including email attachments, malicious downloads, or vulnerabilities in web browsers and online software. Once installed on a victim's computer, Zeus continuously captured sensitive data to send back to the attackers later. Variants of Zeus even had the capability of keylogging, taking screenshots, and stealing login credentials from user activity. This made it a significant threat to everyday users and large organizations alike. Zeus has been known to target financial institutions, government agencies, and corporations, making it a potent cyber weapon.

6. CryptoLocker, a well-known type of malware, encrypts a victim's files and demands payment in exchange for the decryption key. It primarily targets Windows users and has the potential to spread rapidly across networks if not contained. Upon infection, CryptoLocker uses a strong encryption algorithm to lock files, rendering them inaccessible without a password or decryption key known only to the hacker. The attackers then demand payment, typically in the form of Bitcoin or other cryptocurrencies, with ransom amounts varying depending on the victim and the attacker. CryptoLocker falls under the category of ransomware, causing damages worth billions of dollars worldwide each year. It poses a significant threat to critical systems, including hospitals and government agencies, as it can shut them down until a ransom is paid.

7. PlugX, a type of remote access trojan (RAT), is utilized by cybercriminals for advanced persistent threat (APT) attacks. RATs are malicious software that grant attackers remote access to a victim's computer, providing control as if they were physically present. Delivered through targeted phishing emails or software vulnerabilities, PlugX enables attackers to steal data, execute commands, and install additional malware on infected systems. It has been associated with targeted attacks against government agencies, defense contractors, and other high-value targets. PlugX is adept at evading detection by security software, making it challenging to detect and remove from compromised systems.

8. The Nimda virus, discovered in September 2001, is a sophisticated piece of code that spreads through multiple attack routes, including email, websites, and network shares. Nimda combines techniques used in worms, viruses, and Trojan Horse attacks, capable of infecting both servers and workstations running Microsoft Windows. It caused hundreds of millions in damages and could easily spread through common features like email attachments. Unlike other viruses, Nimda didn't aim to cause harm to files or network security. Instead, it employed sophisticated denial-of-service attacks, slowing down entire networks for extended periods of time. Nimda's capability of exploiting known vulnerabilities in web servers allowed it to infect a large number of computers rapidly.

9. Fizzer, a complex worm detected in 2003 by the antivirus firm Kaspersky Labs, spread through various channels, such as email, instant messaging, and file-sharing networks. During its early days, Fizzer rapidly spread through the Kazaa network, infecting numerous computers before being detected. Once installed, Fizzer could execute various malicious actions, including stealing passwords, credit card numbers, and personal data. Additionally, it could disable security software and open back doors for more advanced actions. Some variants of Fizzer were known to send infected emails to the victim's contacts, propagating the infection further. Although not as effective as it used to be, Fizzer remains one of the most widespread viruses in the world.

10. The Circam worm, discovered in July 2001, quickly became one of the most damaging computer viruses of all time. It primarily spread through email and network shares, using various tactics to entice users into opening infected email attachments. Once installed, the worm attempted to spread to other computers on the same network, while simultaneously engaging in harmful activities like deleting files and propagating itself to all contacts in the user's email address book. Circam caused billions in damages and infected millions of computers worldwide, owing to its resilience and highly infectious nature. Its ability to evade detection and removal in many cases made it a substantial security threat. While it is no longer as active, Circam remains a concern for certain legacy Microsoft operating systems still in use for specific purposes.

In conclusion, the menace of computer viruses and cyber-attacks is a persistent and evolving threat that continues to pose significant risks to individuals, businesses, and governments worldwide. Staying vigilant and adopting robust cybersecurity measures is crucial to safeguard against these sophisticated and destructive malware. Organizations and individuals must prioritize regular software updates, employ strong antivirus and anti-malware solutions, and promote cybersecurity awareness among users. The battle against computer viruses and cybercriminals requires a proactive and concerted effort from all stakeholders to ensure a safer digital environment for everyone.