Currently entire World is hit by Ransomware, but there are many more Computer viruses which are equally dangerous. A computer virus is any kind of code that is designed to do harm and spread itself to other systems. It is a malware that, when executed, persistently replicates by reproducing itself or infecting other programs by modifying them. It is created by malicious programmers to use other’s computers to hack other targets or to steal personal information of infected hosts. These computer viruses have inundated computer users for a long time now. Here is a list of the most dangerous computer viruses that have troubled users around the world:
1. Ransomware
It’s a malware designed to steal money from individuals, businesses and other organizations by holding their data hostage. And you know, it is a big business where cyber criminals demands money that range from a few hundred to thousands of dollars and are usually paid in the “virtual” currency Bit coin, which is nearly impossible to trace.
However, this is not the first time this type of attack occurred. In February 2016, L.A.’s Hollywood Presbyterian Medical Center paid a ransom of $17,000 to get its computer systems unlocked. More about Ransomware and its attacks and precautions are here.
2. Melissa Virus
Melissa was the first mass-mailing macro virus for the new age of e-mailing which became the breaking news across the world on March 26, 1999. Melissa was spread in the form of an email attachment by the name “list.doc.” When a person clicked upon the attachment, the virus would find the Microsoft Outlook address book and email itself to the first 50 contacts on the list having a message “Here is that document you asked for. Do not show anyone else.” The virus caused a loss of around $ 600 million. The creator of Melissa, David L Smith was arrested following the biggest internet manhunt of that time and was slapped with 20 months in prison and a fine of $5000.
3. I love You Virus
Perhaps the most virulent computer virus ever created, the I LOVE YOU virus managed to wreck PCs all across the world. Infecting almost 10% of the world’s PCs connected to the Internet, the virus caused a total damage of around $10 billion. The malware traveled the Internet by e-mail and belonged to the worm category. The original worm had the file name of LOVE-LETTER-FOR-YOU.TXT.vbs. The moment someone opened the file, the virus emailed itself to the first 50 contacts available in the PC’s Windows address book. The creators of this virus were two programmers from Philippines. They were arrested but later released.
4. SQL Slammer
On 25 January 2003, the internet broke causing South Korea to lose both internet and cell phone service. Around 300000 people in Portugal could not connect to the internet, airlines were unable to process tickets and had to cancel flights and Bank ATMs went down. All this was caused by a computer virus called Slammer. Slammer was a worm that targeted SQL servers, which store data by using Microsoft software called Microsoft SQL Server. It spread using a bug in the server which reprogrammed the server to replicate the same worm. The worm spread faster than any virus ever had, infecting 75000 servers in just 10 minutes. All this servers were sending requests to thousands of other servers which could not hold all the traffic and eventually broke down. It is estimated to have cause a damage worth $1.2 billion. The programmer behind it was never caught.
5. Storm Worm
The Storm Worm Virus struck the cyber world as a malicious Trojan horse program in late 2006 when users began receiving e-mails with a subject line “230 dead as storm batters Europe,” Which is where the virus gets it name from. The email contained the link to a website which automatically downloaded the virus. The virus was designed to be as invisible as possible. The virus could easily turn any Windows PC into a Bot-net, letting someone offsite operate it remotely. This was used to do all kind of things like sending spam mails, coordinated attacks that could slow down or disable web servers which keep a company going or stealing banking passwords & identity information. This malicious virus is supposed have infected around 2 million computers around the world. The programmers of this virus could not be tracked.
6. Mebroot Virus
Mebroot was a sophisticated Trojan horse program that used stealth strategies to hide itself from the user. The virus opened a back door on the victims computer which allowed the attacker complete access over the computer. The program used to get downloaded without the user noticing it. It woul steal all the information and send it to the Torpig server. By 2008, this virus was estimated to have stolen account information connected to 500000 bank accounts. And again the people who programmed the virus were never caught.
