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.
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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.
Oobesttings error is the blue screen of death error caused by some faulty settings inside the Windows registry. The good news is that this is not a hard error to fix and if by any chance you are one of the unfortunate people getting this dreaded annoying error, please do keep reading because we have several things that you can do in order to eliminate this issue from your computer.
DEL /F /A <file path with extension>Note: In the given command, “/F” is the force delete command, while “/A” is the command that selects the files with the ready for archiving attribute. Step 4: After that, go to the location where you can find the folder you want to delete by using the “cd” command again. And then execute the following command right after:
RD /S <folder path>Note: In the given command, “RD” is the command that removes the folder from the directory, while “/S” removes all of its sub-folders and files. On the other hand, if you also use the “/Q” parameter, you won’t see the “Y/N” confirmation but if you didn’t use it, then simply tap the Y button to proceed.
“We collect information about you, your devices, applications and networks, and your use of those devices, applications, and networks. Examples of data we collect include your name, email address, preferences, and interests; browsing, search and file history; phone call and SMS data; device configuration and sensor data; and application usage.”There are several ways you can disable the utcsvc.exe process. You can disable it using the Service Manager, Registry Editor, and Group Policy Editor. For more details, refer to the instructions laid out below.
“The Connected User Experiences and Telemetry service enables features that support in-application and connected user experiences. Additionally, this service manages the event-driven collection and transmission of diagnostic and usage information (used to improve the experience and quality of the Windows Platform) when the diagnostics and usage privacy option settings are enabled under Feedback and Diagnostics.”
Error 0xc0000142 can occur in any of the Windows versions and usually occurs when an application fails to properly initialize.
This error can be critical for a computer as it signifies that the system is unstable. Error 0xc0000142 can cause slow performance in a PC, system freeze, startup and shutdown issues, blue screen and errors in installation.
Error CausesWindows/Application Error 0xc0000142 can occur because of a number of reasons.
When a computer is an overload with data, or when system files get broken or missing, this error can occur and will result in startup and shutdown issues as well as the blue screen. Another reason, and one which is quite common, is improper computer maintenance.
This will cause a PC to perform slow, system freezes, and installation errors. This error displays ‘failed to initialize’ on either a Windows error box or the blue screen of death.
Error 0xc0000142 can occur at any time, but there are many ways to resolve it. For instance:
A corrupted registry is one of the major reasons why this error occurs. The registry is used by Windows to store information and settings on the computer, which is why it has a large database.
This database contains emails, wallpapers, saved passwords and much more in ‘file path references’. These allow Windows to run the common files in your system. A registry cleaner can fix any errors in the registry database.
Viruses can cause certain applications to not function properly. Hence, download a strong antivirus and run a deep scan on your system and remove any potential infections and spyware.
Non-critical applications in a computer are those that are installed by the user. If error 0xc0000142 displays in any of your installed programs, then you should reinstall these programs. Often applications have damaged or corrupted files which can slow them down. To resolve this, follow these steps:
The third step is not recommended in case the error is caused by cmd.exe
If the error is still on display despite following the previous steps, then you can repair Windows. This process allows Windows to retain all your data and information by simply replacing the program files and settings with fresh ones. This can stop error 0xc0000142 by allowing the programs access to use necessary files smoothly and effectively.
If you cannot resolve the error in any of these steps, then there is another way to do so if you have a computer that runs the Microsoft Internet Security and Acceleration (ISA) Server 2000. Follow these steps in order to resolve it:
Good thing is that website or web application will prompt you to allow it to use this feature like when a site/application wants to use your microphone or web camera. Developers are on board with this feature since it can provide them with more telemetric data on how users are interacting with their website/application but there are some that are strongly voicing against this.
Tantek Çelik, Mozilla Standards Lead, commented on GitHub, saying:
As it is currently specified, I consider the Idle Detection API too tempting of an opportunity for surveillance capitalism motivated websites to invade an aspect of the user’s physical privacy, keep long-term records of physical user behaviors, discerning daily rhythms (e.g. lunchtime), and using that for proactive psychological manipulation (e.g. hunger, emotion, choice)… Thus I propose labeling this API harmful and encourage further incubation, perhaps reconsidering simpler, less-invasive alternative approaches to solve the motivating use-cases.Others who have spoken against this feature are people from the WebKit development team inside Apple. Ryosuke Niwa, an Apple software engineer who works on WebKit said:
That doesn’t seem like a strong enough use case for this API. For starters, there is no guarantee that the user won’t immediately come back to the device. Also, who is such a service supposed to know what another device user might be using at any given point? We’re definitely not going to let a website know all the devices a given user might be using at any given point. That’s a very serious breach of the said user’s privacy. It seems to me that such a suppression/distribution mechanism is best left for the underlying operating systems/web browsers to handle.Of course, technology itself as always can be used for good or for bad and time will tell if this feature has brought good stuff or it has paved another brick in surveillance and privacy manipulation. As said for now option will prompt for agreement and let's hope that it will be used for good causes from this day into the future.
Rollback using system restore