When we talk about computer viruses , what will come to your mind is malicious software that infects your device and causes some damages such as file loss, device slowdown, spyware and information theft and other technical damage that does not exceed the limits of your computer, but have you ever thought whether computer viruses can Causing significant damage on the ground and affecting the real lives of millions of people around the world? Or even causing a global pandemic? In fact, computer viruses cause severe annual losses estimated at billions of dollars, but there are some names that have made a mark in the history of the computer, and deserved the title of the worst and most lethal computer viruses in history due to the enormous damage they caused on the ground, we will mention 5 names in this article .
Mydoom
Mydoom is a computer worm that appeared in 2004 that infects computers running Windows. This worm spreads through e-mail messages, as it appears as a message titled “Error sending e-mail” (“Error”, “Mail Delivery System”, “Test”, “Mail Transaction Failed”...) and inside that message is the infected email attachment which, after running, the worm sends infected emails to every email in the address book of the infected machine and publishes itself within the network, so Mydoom becomes one of the fastest Email worms are prevalent.
And if you're wondering what exactly the virus is doing, it has been connecting infected machines to a network of computers that are carrying out DDOS attacks whose goal is to shut down a targeted site or server. The Mydoom virus has caused financial losses estimated at US$38 billion on the ground, possibly originating in Russia.
ILOVEYOU
ILOVEYOU Another virus (computer worm) that has earned the title of one of the worst computer viruses in history due to the losses it caused, estimated at 10 billion US dollars, appeared in the year 2000 and originated in the Philippines. You receive the virus on the e-mail via a normal message with the address ILOVEYOU , its content is one line urging you to open the attached file, which is supposed to contain a “love letter” from the sender, and of course this is only a bait to make the recipient open the attached file (the virus), which is the phrase about script.
Well, what does a virus do after running it? . . . It simply copies itself into the system folders and then the registry to run every time you start the system, and then tampers with the Internet Explorer browser (remember that we are talking here about the year 2000) to download a Trojan that steals passwords and of course then adjusts the registry to make the Trojan work in every time the system is started. Then the Trojan performs its job, which is to steal the saved passwords on your device and send them to a specific email that belongs to the owner of the virus, who is a university student who lacks money. He created this virus so that he could steal accounts and use Internet services for free. After that, the virus sends itself to all the mailing list saved on the infected device, and finally the virus begins to tamper with the files on the device and overwrite them (create new files and delete the original files) .
In addition to the $10 billion losses, it is believed that 10% of the world's computers were infected with the ILOVEYOU virus , although the numbers are not sufficient to reveal the extent of the damage caused by the ILOVEYOU virus on the ground, knowing that a number of governments and large companies (British Parliament, Ford Company ...etc) turning off their email systems to protect against the virus will suffice.
WannaCry
All of the previous viruses may not have been heard of because they are a bit old, but the WannaCry ransom virus has certainly heard about it in recent years, specifically from 2017, when it was similar to a global epidemic. WannaCry is a malicious program used to extort money, as it seizes the Windows computer, with all the files inside it and encrypts them or holds them hostage, if you will, in exchange for a ransom of $ 300 in Bitcoin (later it became $ 600) that the victim demands to pay To decrypt its files and restore them. If the victim does not pay the claimed ransom within 3 days, their files will be permanently deleted.
The WannaCry ransomware virus has spread to about 150 countries, infecting a huge number of computers (about 230,000 devices), causing paralysis in many companies, hospitals, and government organizations, as well as causing huge losses estimated at 4 billion US dollars around the world.
CryptoLocker
Before WannaCry, specifically in 2013, a fierce ransomware virus known as CryptoLocker appeared, and it was one of the most dangerous types of ransomware. CryptoLocker is a Trojan that targets Windows machines and spreads via emails (infected attachment) . When it infects your device, it encrypts your files and asks you to pay a certain ransom via Bitcoin ($400) in exchange for decrypting your files and returning them to you again. .
After the arrest of the leader of the group that created this virus, the decryption keys were released and made available to the public so that the 500,000 victims were able to decrypt their files for free. As for the losses, there is no specific number, but the closest thing is what the famous ZDNet website has done . Bitcoin addresses are posted by users infected with the CryptoLocker ransomware , and the results are $27 million transferred to those addresses (some sources have reported double figures based on the average cost of losses caused by ransomware attacks to businesses).
Sasser
Sasser is a computer worm that appeared in 2004, infects Windows devices, made by a 17-year-old German computer science student at the time named Sven Jaschan , and the cost of damage caused by the Sasser virus was estimated at 18 billion dollars. When the Sasser virus infects the computer, it slows it down and causes it to crash, and it also makes it very difficult to shutdown without cutting off the power to the device. This may seem to you a simple thing and will not have that significant impact on the ground, but the reality was exactly the opposite, with more than a million computers infected with this virus, it had a severe impact on airlines, public transportation, news agencies, companies, Hospitals, banks... and others, all of this had devastating effects on people's real lives.
Unlike other computer worms, Sasser was not spread via e-mail, but rather by means of a vulnerability present in the Windows system at the time. When the virus infects your computer, it searches for other systems that are weak or not immune from the vulnerability, then contacts them and infects them with the virus.
In conclusion, as you can see, computer viruses may have destructive damage on the ground, and they may transfer to your device quite easily, so it is better to take your precautions first, as you know “prevention is better than cure” , and therefore I advise you to read the very important topic Five steps to protect your device from viruses computer . Finally, I would like to tell you that the list is random and not ordered on any basis, and of course there are many other viruses that deserved the title of the worst computer virus, but I did not mention them, and I contented myself with only what I found interesting.