Computers viruses, worms, ransomware, etc. are kinds of malicious software that no user should take lightly. On several occasions, we have touched upon security steps that each user should take in order to protect its identity and data. Sadly sometimes even when all precautions are taken some malware can still slip through and wreak havoc. Today we are looking at some of the worst or the best, depending on your view that has indeed wreaked plenty of havoc.
10 worst computer viruses in historyIn the list of the 10 most famous computer viruses below, we show the costs, dates, reach, and other key facts. First a note about terms: we use the words “virus” and “worm” interchangeably because most readers search for them that way. But there’s a subtle difference that we explain after the list.
The worst computer virus outbreak in history, Mydoom caused estimated damage of $38 billion in 2004, but its inflation-adjusted cost is actually $52.2 billion. Also known as Novarg, this malware is technically a “worm,” spread by mass emailing. At one point, the Mydoom virus was responsible for 25% of all emails sent.
Mydoom scraped addresses from infected machines, then sent copies of itself to those addresses. It also roped those infected machines into a web of computers called a botnet that performed distributed denial of service (DDoS) attacks. These attacks were intended to shut down a target website or server.
Mydoom is still around today, generating 1% of all phishing emails. That’s no small feat considering the 3.4 billion phishing emails sent each day. By that figure, Mydoom has taken on a life of its own, infecting enough poorly-protected machines to send 1.2 billion copies of itself per year, 16 years after its creation.
Though a $250,000 reward was offered, the developer of this dangerous computer worm was never caught.
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The 2003 Sobig computer virus is actually another worm. It is second only to the Mydoom virus in its scope. The $30 billion figure is a worldwide total, including Canada, the U.K., the U.S., mainland Europe, and Asia. Several versions of the worm were released in quick succession, named Sobig.A through Sobig.F, with Sobig.F being the most damaging.
This cybercriminal program masqueraded as legitimate computer software attached to emails. It disrupted ticketing at Air Canada and interfered with countless other businesses. Despite its widespread damage, the creator of the successful bug was never caught.
Klez is a close third on the list of the worst computer viruses ever created. With nearly $20 billion in estimated damages, it infected about 7.2% of all computers in 2001, or 7 million PCs. The Klez worm sent fake emails, spoofed recognized senders and, among other things, attempted to deactivate other viruses.
As with other viruses and worms, Klez was released in several variants. It infected files, copied itself, and spread throughout each victim’s network. It hung around for years, with each version more destructive than the last.
Windows has come a long way since most of the computer viruses on this list hit the web. Thankfully, built-in protection with Microsoft Defender is always on the watch.
The year 2000’s ILOVEYOU virus worked by sending a bogus “love letter” that looked like a harmless text file. Like Mydoom, this attacker sent copies of itself to every email address in the infected machine’s contact list. Shortly after its May 4 release, it had spread to more than 10 million PCs.
The virus was created by a college student in the Philippines named Onel de Guzman. Lacking funds, he wrote the virus to steal passwords so he could log into online services he wanted to use for free. He reportedly had no idea how far his creation would spread. This virus is also known as Loveletter.
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The 2017 WannaCry computer virus is ransomware, a virus that takes over your computer (or cloud files) and holds them hostage. The WannaCry ransomware ripped through computers in 150 countries, causing massive productivity losses as businesses, hospitals, and government organizations that didn’t pay were forced to rebuild systems from scratch.
The malware raged like wildfire through 200,000 computers worldwide. It stopped when a 22-year-old security researcher in the U.K. found a way to turn it off. Computers with out-of-date operating systems were hit especially hard. That’s why security experts always recommend updating your systems frequently.
In September 2020, one of the potentially largest computer virus attacks in medical history hit Universal Health Services. The U.S. hospital chain, which has more than 400 locations, was reportedly struck by damaging ransomware. The attack forced the cancellation of surgeries and made healthcare workers switch to paper records.
The Zeus computer virus is an online theft tool that hit the web in 2007. A whitepaper by Unisys three years later estimated that it was behind 44% of all banking malware attacks. By then, it had breached 88% of all Fortune 500 companies, 2,500 organizations total, and 76,000 computers in 196 countries.
The Zeus botnet was a group of programs that worked together to take over machines for a remote “bot master.” It originated in Eastern Europe and was used to transfer money to secret bank accounts. More than 100 members of the crime ring behind the virus, mostly in the U.S., were arrested in 2010. It’s not as prominent today, but some of the virus’ source code lives on in newer botnet viruses and worms.
Zeus caused documented damage of $100 million. But the real cost in terms of lost productivity, removal, and undocumented theft is undoubtedly much higher. A $3 billion estimate, adjusted for inflation, puts this virus at a cost of $3.7 billion in today’s dollars.
First observed in 2001, the Code Red computer virus was yet another worm that penetrated 975,000 hosts. It displayed the words “Hacked by Chinese!” across infected web pages, and it ran entirely in each machine’s memory. In most cases it left no trace in hard drives or other storage.
Financial costs are pegged at $2.4 billion. The virus attacked websites of infected computers and delivered a distributed denial of service (DDoS) attack on the U.S. White House’s website, www.whitehouse.gov. In fact, the White House had to change its IP address to defend against Cod Red.
Can your printer get a virus? See our cool infographic: The State of Printer Security
The SQL Slammer worm cost an estimated $750 million across 200,000 computer users in 2003. This computer virus randomly selected IP addresses, exploiting vulnerabilities and sending itself on to other machines. It used these victim machines to launch a DDoS attack on several internet hosts, significantly slowing internet traffic.
The Slammer worm hit banks in the U.S. and Canada especially hard, taking ATMs offline in many locations. Customers of Toronto’s Imperial Bank of Commerce found themselves unable to access funds. The attack reared its ugly head again in 2016, launching from IP addresses in Ukraine, China, and Mexico.
Thankfully, ransomware attacks like the 2013 CryptoLocker virus have dipped since their 2017 peak. This malware attacked upwards of 250,000 machines by encrypting their files. It displayed a red ransom note informing users that “your important files encryption produced on this computer.” A payment window accompanied the note.
The virus’ creators used a worm called the Gameover Zeus botnet to make and send copies of the CryptoLocker virus. According to a report by security firm Sophos, the average ransomware attack costs a business $133,000. If we estimate that CryptoLocker hit 5,000 companies, that would put its total cost at $665 million.
Where will cybersecurity go next? See our guide: The Future of Cybersecurity
The Sasser worm was written by a 17-year-old German computer science student named Sven Jaschan. He was arrested at the age of 18 in 2004 after a $250,000 bounty was posted for the computer virus’ creator. A friend of Jaschan’s tipped authorities that the youth had penned not only the Sasser worm but also the damaging Netsky.AC attack.
Jaschan was given a suspended sentence after it was found he was a minor when he wrote the malware. The Sasser worm crashed millions of PCs, and though some reports put damages at $18 billion, the relatively low infection rate suggests a more likely cost of $500 million.
Other notable viruses
The top 10 worst computer viruses above are just the ugly tip of a gargantuan digital iceberg. With a million new malware programs popping up every 3 years, we may miss the forest for a few outstanding trees. Here are just a few more viruses that have wreaked havoc over the years:
Mimail: This worm tried to harvest data from infected machines to launch a string of DDoS attacks, but was relatively easy to remove.
Yaha: Yet another worm with several variants, thought to be the result of a cyber-war between Pakistan and India.
Swen: Written in C++, the Swen computer worm disguised itself to look like a 2003 OS update. Its financial cost has been pegged at $10.4 billion, but not reliably.
Storm Worm: This worm showed up in 2007 and attacked millions of computers with an email about approaching bad weather.
Tanatos/Bugbear: A 2002 keylogger virus that targeted financial institutions and spread to 150 countries.
Sircam: A computer worm from 2001 that used counterfeit emails with the subject line, “I send you this file in order to have your advice.”
Explorezip: This worm used fake emails to spread to every machine on thousands of local networks.
Melissa: The most dangerous computer virus in 1999, Melissa sent copies of itself that looked like NSFW pics. The U.S. FBI estimated cleanup and repair costs at $80 million.
Flashback: A Mac-only virus, Flashback infected over 600,000 Macs in 2012 and even infected Apple’s home base in Cupertino, Calif. In 2020, there’s now more malware on Macs than on PCs.
Conficker: This 2009 virus still infects many legacy systems and could do significant damage if it ever activates.
Stuxnet: This worm is reported to have destroyed Iranian nuclear centrifuges by sending damaging instructions.
Microsoft has announced Windows 365, a new cloud-based operating system aimed mainly at businesses of all sizes.
Just after Windows 11 announcement and presentation, we are seeing another Windows announcement from Microsoft. Dive into the following text in order to find out what exactly is new Windows 365, its role in today's IT world, and do you need it?
This specific Windows 8.1 or Windows 10 error code has to do with the number of times you can use your license number to install windows programs on computers. All windows activation codes are licensed to be used one time for a device, to control piracy, but what happens when your PC crashes, or you have to change a hard drive component and are forced to re-install Windows Operating System. Luckily, there is an easy fix for this issue.
Error CausesBasically, when you need to re-install the Windows operating system that you have previously bought and installed on another computer an error code will be displayed with a message telling you that the activation server determined that the specific key could not be used for activation. This occurs because the key has already been used on that computer, or a different one, to install operating systems. There are a few easy fixes for this issue, and most of them should be easily completed on your own.
There aren’t many explanatory ways to repair Error Code 0xc004c008. Below are two methods to go about addressing this issue.
If the first method did not work, the only other option is to call Microsoft and walk through the process with a technician. To do this, dial “1-800-936-5700”. Explain the error that you received and the steps in the update process during which it was displayed. The technician will be able to walk through the steps from getting a new product key to finishing the installation.
If you're not a tech-savvy individual but would like to solve this problem without the aid of a technician, download a powerful automated tool to fix error code 0xc004c008.
Stop c000021a {Fatal System Error} The session manager initialization system process terminated unexpectedly with a status of 0xc0000017 (0x00000000, 0x0000000) The system has been shut down.
jZip is a software utility published by Bandoo Media and is classified as a Potentially Unwanted Program. The software is an archive tool that used to compress and extract files in the rar, zip, and other formats. The program is typically bundled upon installation with other unwanted applications and is itself often installed in co-bundles. As of publication time, over 40 AntiViruses have flagged jZip as malicious or potentially unwanted.
It injects itself in Windows shell, providing quick access to the program by right-clicking on any file. jZip displays it's advertising in your browser, instead of the default search results, to better do this, it collects information about your browsing history and your current browsing session, so it can better target ads. This software, upon install, defines an auto-start registry key in your system, this allows the software to launch every time your computer is rebooted, no matter what Windows account you log in to, it also adds Windows Tasks, to allow it to launch by itself at random times, even when closed.“C:>Dism /Online /Cleanup-Image /RestoreHealth /Source:c:testmountwindows /LimitAccess Deployment Image Servicing and Management tool Version: 10.0.10586.0 Image Version: 10.0.10586.0 [==========================100.0% Error: 14098 The component store has been corrupted. The DISM log file can be found at C:WINDOWSLogsDISMdism.log C:>”There are several fixes you can check out to fix the DISM Error 14098, “The component store has been corrupted”. You can try to run the Restore Health command or reset the Windows Update components, or whitelist the dism.exe in your antivirus program, as well as try to uninstall any recently installed updates. Follow the options provided below for more details.
Problem signature: Problem Event Name: BlueScreen OS Version: 6.0.6002.2.2.0.16.7 Locale ID: 1033When the error occurs, the computer screen turns blue and the user is unable to view or access the program. It is advisable to fix the error right away, virtually because BSoD is a critical PC error, it can pose serious threats to your system.
You don’t need to hire a technician or be a computer whiz to resolve Blue Screen Locale ID1033 error code. Here are some methods that you can try to resolve this error on your PC. These methods are easy to perform and result-driven.
Nectar Toolbar is a Browser addon for Internet Explorer developed by AIMIA Coalition Loyalty. This addon changed your default search provider to Yahoo UK. While installed, you might see additional unwanted ads and sponsored links injected in the search results.
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Several anti-virus scanners have marked this addon as a Browser Hijacker and are therefore not recommended to keep on your computer.
Error Causes“Sfc /scannow”
Error Code 0x8007001 occurs during installations that take place in Windows 10. Various versions of this same error have also been present in previous editions of the software and the methods to resolve the error across these versions are the same
Common symptoms include:
Several solutions for Error Code 0x8007001 require the user to complete semi-complex tasks. If you aren’t comfortable with the processes necessary to finish the methods below, make sure that you get in touch with a certified professional who is familiar with the Windows operating system to assist you in the resolution of the error code.
Error CausesIn many cases, Error Code 0x8007001 is caused by an installation disk that is not functioning properly or installation files that have been corrupted or changed. When this is the case, the operating system will not be able to begin actually installing the files and will instead hang up as the files are unpacked from the installation set.
For Error Code 0x8007001 to be repaired properly, the missing or corrupted installation files need to be repaired or the system needs to be able to recognize the files that it is missing. This can require some advanced computing knowledge. If you don’t feel comfortable with the idea of undertaking the methods below on your own, contact a computer repair technician who can assist you in following these steps.
In some cases, the operating system simply cannot recognize the installation files that are present on the disk in question, whether it is on a hard drive, a set of downloaded files, or files from a flash drive. If this is the case on your particular machine, the simplest way to work around the problem is to load the installation files onto an alternative disk source, whether it be a flash drive, CD, DVD, or secondary hard drive. After these files have been properly loaded onto that alternative disk, attempt to run the installation from the alternative source instead.
If this method is successful, it means that the system may have had trouble recognizing the files involved in the installation from the first source, but that the files themselves were not corrupted or changed.
Make sure that you save the alternative disk source after your installation is complete in case you ever need to do a fresh installation on your machine.
If you are installing files from a DVD or CD, check to make sure that the back of the disc is free from scratches and dust. If there are no visible marks on the disc, you may need to open up your disk drive to see if there is a build-up of dust or debris inside of the drive. If this is the case, simply clean your drive and re-attempt your installation process from the included disk.
If the error code is still appearing on your machine, you can open up your Windows Update tool and run the troubleshooting wizard, which will then scan your machine to see if there are any potential problems that it can fix. Next, run the Update tool itself if there are any updates that need to be performed. Sometimes, this can resolve the error at hand. Make sure to restart your computer after any updates or changes have been made so that you can ensure that they are applied by the operating system appropriately.
