Top 5 Deadliest Computer Viruses in History

Many users have been infected with a computer virus in some form or another. To the majority of individuals, it's just a little irritation that needs a clean-up and the installation of that antivirus program you've meant to install but never did.

In other cases, though, it might be a complete disaster, turning your computer into a costly brick from which no amount of antivirus can protect you.

In this list, we'll look at some of the worst and most well-known computer viruses that have wreaked havoc in real life. Because worms and trojan horses are frequently confused for viruses, we've included them as well. These viruses have cost billions of dollars in damages and have disrupted important real-world infrastructure.

The ten most well-known and dangerous computer viruses are listed here.

1. I LOVE YOU

ILOVEYOU is regarded as one of the most dangerous computer viruses ever devised. It was able to wreak havoc on computer systems worldwide, causing roughly $10 billion in losses. It was estimated that 10% of the world's computers were infected. The situation was so terrible that governments and huge organizations shut down their email systems to avoid contamination.

Leonel Ramones and Onel de Guzman, two Filipino programmers, designed the virus. It used social engineering to get people to open the attachment, which was a love confession in this case. Because Windows at the time obscured the file's true extension, the attachment was essentially a script masquerading as a TXT file.

It will then email itself to everyone on the user's mailing list and overwrite all of the data on the machine, rendering it unbootable. Because there were no laws against viruses, the two were never charged. As a result, the E-Commerce Law was passed to address the issue.

2. Code Red

Code Red was first identified in 2001 by two eEye Digital Security personnel. It was given the moniker Code Red since the two were drinking Code Red Mountain Dew when they discovered it.

The worm preyed on machines using Microsoft's IIS web server, taking advantage of a buffer overflow flaw in the system. It can run totally on memory, with a footprint of 3,569 bytes, leaving a virtually minimal trace on the hard disc.

Once infected, it will generate a hundred copies of itself, but owing to a design flaw, it will replicate, even more, using a large portion of the system's resources.

It will then conduct a denial of service assault against several IP addresses, the most well-known of which was the attack on the White House website. Backdoor access to the server is also possible, allowing for remote access to the system.

The most memorable symptom is the statement "Hacked By Chinese!" that appears on infected web pages and has since become a meme. After a patch was published, it was estimated that $2 billion in productivity was lost. When you consider that there were 6 million IIS servers at the time, a total of 1-2 million servers were affected.

3. Melissa

David L. Smith invented it in 1999 and named it after an exotic dancer from Florida. It began with an infected Word document purporting to be a list of passwords for pornographic websites posted to the alt. sex Usenet group. This piqued people's interest, and when they downloaded and opened it, the macro within would activate and unleash its payload.

The virus will send itself to the top 50 persons in the user's email address book, causing a surge in email traffic and interrupting government and corporate email networks. It also has a habit of corrupting documents by inserting a Simpson's allusion.

When the Word document was traced back to Smith, he was apprehended. The material was uploaded using a stolen AOL account, and law enforcement could apprehend him with their assistance less than a week after the outbreak began.

He worked with the FBI to apprehend other virus creators, including the famous Anna Kournikova virus creator. He spent only 20 months of his ten-year sentence and paid a fine of $5000 in exchange for his cooperation. The virus is said to have cost $80 million in damages.

4. Sasser

Sven Jaschan, a computer science student who also built the Netsky worm, designed a Windows worm initially found in 2004. While the payload itself is irritating (it slows down and crashes the machine and makes it difficult to restore without turning off the power), the consequences were massive, with millions of computers infected and crucial infrastructure disrupted.

The worm used a buffer overflow vulnerability in the Local Security Authority Subsystem Service (LSASS), which manages local account security policies, to crash the computer. It will also use system resources to spread itself across the Internet and infect other PCs automatically.

The virus's effects were widespread because many machines had not been updated even though the exploit had already been patched. More than a million people were infected, and vital infrastructures such as airlines, news organizations, public transit, hospitals, and public transportation were all affected. The total cost of the destruction was projected to be $18 billion. Jascha was sentenced to a 21-month suspended sentence after being convicted as a minor.

5. Zeus

Zeus is a Trojan horse designed to infiltrate Windows systems and perform a variety of nefarious activities. Maman-in-the-browser logging and form snatching is the most common of these tasks. Drive-by downloads or phishing schemes were used to infect the majority of machines.

It was first discovered in 2009 and has since infiltrated hundreds of FTP accounts and computers belonging to huge international organizations and banks, including Amazon, Oracle, Bank of America, Cisco, and others. The Zeus botnet's operators exploited it to steal login credentials for social media, email, and banking accounts.

More than 1 million computers were infected in the United States alone, with 25% of those infected in the United States. The operation was sophisticated, including people from all over the world acting as money mules to smuggle and transfer funds to the Eastern European ringleaders.

A total of $70 million was taken and held by the ring. In connection with the operation, 100 persons were arrested. The developer of Zeus declared his retirement in late 2010, although many analysts believe this is fake.