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.
Wondering what makes the world’s most secure computers so safe? See the Tech@Work guide: Upgrade to the World's Most Secure and Manageable PC
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.
Need to up your remote work security game before there’s another entry on the list of most deadly computer viruses? See our guide: How to Work Remotely and Securely
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.
This is the second large game company acquisition by Microsoft, Acquiring Bethesda first and a big hit to Sony since Xbox will now have more games in its catalog and as exclusives.
Of course, the sale has to go through the standard closing conditions and completion of regulatory review and Activision Blizzard’s shareholder approval before it’s finalized. Assuming that all goes well, the deal is slated to be completed during the fiscal year 2023, which is July 1, 2022, through June 30, 2023. resource setautoreset true C:
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A runtime error is commonly an error that's created after the PC is operating software and encounters a problem of some form. For instance, a runtime error like run-time error code 7 reveals an "out of memory" dilemma.
Run-time errors are normally brought on by clashes with TSR (Terminate and Stay Resident) applications or additional operating applications, software problems, storage problems, or pc viruses.
First, enter the run-time error signal into a search engine to see what info you will get about the precise runtime issue you are receiving. Next, end - job all running applications and TSRs to make sure these aren't the origin of the issue. You can certainly do so by obtaining the job manager by striking Control Alt Delete.
In case your issue is regularly occurring with a unique program, go to that system programmer's site and obtain any upgrades and patches. If unavailable, try uninstalling the application involved and reinstalling it.
In the event the issue is occurring with the os, you may consider reinstalling it although it is a huge commitment. A much better idea would be to try a fix for both Windows XP or Windows 2,000. It is possible to fix and scan files by typing : sfc / scannow, heading to the Begin switch, Run, and then pushing enter. Make certain to put an area between sfc and the reduce.
You might have an equipment or storage dilemma if these measures have not resolved your run-time errors. If that is the situation, contact the support of the application under consideration for potential support accompanied by the pc or motherboard manufacturer.
Many run-time problems can be solved by upgrading the application that's creating the problem. This is only because the programmer's frequently releasing patches and improvements for their applications as insects are found and repaired.
Storage problems may frequently be fixed by rebooting the pc. Consider a reboot a short-term repair. Rebooting clears the memory but in case your COMPUTER does not have adequate memory for your applications you're operating, or sufficient hard-drive space you'll immediately run out of memory again. Something less than this sum may cause memory issues since the computer's swap file isn't in a position to expand in dimension as required.
To assess the quantity of free area, available My Computer and right-click on the HDD, generally the D: drive. Select Attributes in the menu and see the disc's ability. Perform the disk clean-up function by following prompts and pressing the Disk Clean-up button, if the room is reduced.
You may be getting run-time errors, in case your storage chip is really failing. Eliminating and changing the awful memory chip will solve the difficulty. If you're encountering other runtime-related errors, like an install runtime issue, try cleaning away the portions of the registry with some software solution.
Error code 0x803f7001 results when users fail to update their Windows operating system. This often occurs when they seek to update from Windows 8 or 8.1 to Windows 10. Users will be able to identify error code 0x803f7001 because of the following common symptoms which occur:
Error CausesThe causes for error code 0x803f7001 are usually associated with the use of an unlicensed version of Windows 8 when upgrading to Windows 10. In such cases, the error code occurs when there is no valid Windows license or product key on your device.
To fix error code 0x803f7001, users may not necessarily need technical knowledge or the help of a Windows repair technician. Usually, the process is simple and can be resolved with the use of a valid product key. However, if users have trouble implementing the instructions found in the manual repair methods listed below, contact a Windows repair specialist for help or use an automated tool that provides the best solutions for problems like error code 0x803f7001.
A product key is a 25-character code that enables users to activate their Windows operating system. To successfully activate your operating system and resolve error code 0x803f7001, enter the product key in the correct order. Once you have a valid product key in your possession, begin to resolve the error code by following the instructions below:
Once you type in the valid product key, you should be able to successfully upgrade to the latest version of Windows. However, this method is only effective if the error code 0x803f7001 on your device is caused by issues related to the product key.
If the error code reappears after attempting manual repair method one, move to the next manual method suggested below.
This method is crucial for you to perform if method one was not successful. Begin the reinstallation process by ensuring you have a genuine version of Windows 8. After reinstalling this version of your Windows operating system, attempt to upgrade to Windows 10 by following the instructions below:
If this method is successful, you will no longer see error code 0x803f7001 pop up in a message box. You will also be able to access Windows 10, and all the benefits it provides users, on your device.
Automated tools help PC users eliminate common issues such as Windows error codes. To address or rectify error codes like error code 0x803f7001 download a powerful automated tool on your machine. This tool enables users to access quick solutions. It also scans for and corrects issues that may result in error codes or poor PC performance.
“Windows cannot start new hardware devices because the system hive is too large (exceeds the Registry Size Limit), (Code 49)”There are instances when it may so happen that the device or devices are no longer attached to the computer but they are still listed in the system hive of the registry. For instance, if you were removing hardware and application for years but they weren’t removed from the registry then the size of the system hive keeps on growing until it hits the maximum limit. As you know, making changes in the registry manually, no matter how knowledgeable you are on such things is not sage since the registry is not only important but also complex. In addition, the System Hive is also a permanent part of the Registry associated with a set of files that contain information related to the configuration of the computer on which the OS is installed. To resolve this error, you must remove or uninstall any hardware devices that are no longer in the system. In fact, the Device Manager hides them by default so you need to enable hidden or non-present devices. Follow the instructions given below to set the Devices Manager to display devices that are no longer connected to the computer. Step 1: Tap the Win + R keys to open the Run dialog box. Step 2: After that type in “cmd” and hit Enter to open the Command Prompt. Step 3: Type “set devmgr_show_nonpresent_devices=1” in the Command Prompt and hit Enter to enable the hidden devices option. Step 4: After that, exit Command Prompt and tap Win + X + M to open the Devices Manager. Step 5: After opening the Devices Manager, click on View and then select the “Show hidden devices” option. This will show you all the devices that are not connected to the computer but are still mentioned. Step 6: Next, select a non-present device and click Uninstall from the Driver tab. Step 7: After that, repeat what you’ve done on step 5 for any other device that you no longer use. Step 8: Restart your computer. You can check the device Properties dialog box in the Device Manager after you’re done removing all the useless devices, to check if the error is now fixed or not. Moreover, you can also try running the Hardware and Devices Troubleshooter as it can also help resolve hardware-related problems. To use it, refer to the steps below.
Windows 7 features Troubleshooting Wizard, an automated tool that helps users resolve several PC-related problems such as accessing shared files or internet connectivity to name a few.‘An unexpected error has occurred’- The troubleshooting wizard can’t continue
Error code: 0x80131700'
