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.
reg add HKLMSYSTEMCurrentControlSetControlBackupRestoreFilesNotToBackup
net stop wuauserv net start cryptSvc net start bits net start msiserver
net start wuauserv net start cryptSvc net start bits net start msiserver
From the settings screen, choose Personalization.
Under personalization options click on START.
And then on the right part click on the button under Use Start full screen to turn it ON
That's it, your start menu is now full screen. VSSControl: 2147467259 Backup jobs failed. Cannot create a shadow copy of the volumes containing the writer’s data. VSS asynchronous operation is not completed. Code: [0x8004231f]This message pops up when you are creating a snapshot system restore, usually, the issue is tied with insufficient space or service stopping. We will go into detail about how to fix both so you can finish the operation without any issue.
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The look is also similar with Scorpion being more sinister-looking but overall Steel frame and chair are the same.
Error code 0x800ccc0f is an error that occurs when users attempt to send/receive emails in Outlook or Outlook Express. Though information regarding the error is limited and sometimes difficult to decipher to those unfamiliar with error code issues, the following are possible symptoms users can expect when this error occurs:
Error CausesErrors in Outlook or Outlook Express may occur due to a multiplicity of reasons. It may be due to a problem with your network connection or the server. You may also encounter this problem after an extended period of inactivity.
Since the error could be due to one of many issues, several solutions are recommended. However, note that these suggestions require you to make changes that come with various risks. Be sure to implement these instructions correctly to avoid causing more problems to occur.
If you are not confident that you will be able to successfully implement the solutions below, get help from a certified Windows technician or IT professional.
As with other error codes, manual procedures are available which users can take to correct the problem. To implement manual repair, follow the methods suggested below:
Since error code 0x800ccc0f may manifest itself due to an issue with your network, you can seek to rectify the problem by first checking your connection. To do this, open an Internet browser. Type a valid web address in the address bar and click Enter.
If you are unable to access the website, you may then seek to fix the Internet connectivity issue by using Microsoft Automated Troubleshooting Services. These free tools are available for download on Microsoft’s website.
Not only can these tools fix your Windows Firewall – if this is the cause of your connectivity issues. These automated troubleshooting tools can also resolve other issues related to your Internet browser or network.
However, if after downloading and running these tools error code 0x800ccc0f still persists in Outlook or Outlook Express, implement the solution below.
Verifying your network connection is another way you can resolve your Outlook issues, i.e. once the issue is in fact a network-based problem.
To verify your network connection, make sure your computer’s network devices are turned on and fully functioning. Also ensure that the cables that connect your computer to a network are secure. You may also contact your Internet Service Provider (ISP) to verify your connection.
If there is no issue with your network and error code 0x800ccc0f persists, you will need to implement method three.
Problems with sending or receiving email messages based on the 0x800ccc0f error code could also be due to configuration issues for individuals who connect using a router. If this is a misconfiguration issue, you may be able to resolve the problem by bypassing the router and connecting through your modem.
Before doing this, however, be sure to check if your firewall is turned on as connecting directly can leave your machine vulnerable. Prevent attacks by checking your Windows Firewall setting. After making adjustments where necessary to ensure the firewall is turned on, test your connectivity to ensure you can access a connection. Also, check Outlook to see whether the error message has been resolved. If the error persists, consider the next solution.
Third-party apps like anti-virus software can sometimes cause interference, leading to errors. For this reason, check if the antivirus on your device is the source of the issue. Start by disabling the antivirus software. You may also turn off the software’s email scanning feature to verify whether or not that is the cause of the error.
Note that disabling your antivirus is only a temporary solution as it is not recommended that you use your computer without such protection in place. Consider replacing your antivirus or uninstalling and reinstalling for a permanent fix if indeed your issue with error code 0x800ccc0f was caused by interference from third-party apps.
Also, consider downloading a powerful automated tool to protect your machine from possible errors in the future.
Error CausesCHKDSK [volume [[path] filename]] [/F] [/V] [/R] [/X] [/C] [: size]]Note: In the command given above, “[/F]” will try to fix the system errors while “[/R]” will be the one to fix the bad sectors.
