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.
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.
ConvertDocsOnline is a Browser Extension for Google Chrome developed by Mindspark Inc. This extension offers users a quick and easy way to convert documents without any additional applications installed on their computer, it also has quick access links to popular websites that the average user might find interesting. While all this may look appealing and nice, this extension injects itself into your browser.
While installed, ConvertDocsOnline will monitor your browsing activity and record visited websites, clicked links, downloads, and even viewed products. All this information is later used/sold to Mindsparks Ad network to better serve user-targeted ads.
Browsing the internet with this extension installed will result in ad placement throughout your browsing sessions. These ads might appear as normal links (sponsored content), ad links, or even pop-up ads.
ConvertDocsOnline has been marked as a Browser Hijacker by several Anti-Virus scanners and is therefore recommended for optional removal from your PC.
C00D1199: Cannot play the file
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.
Error CausesAre you trying to update your Windows 11 OS and are receiving a 0x800f0905 error? Do not sweat and do not worry we have a couple of solutions that you can try in order to fix this issue. How this error is tied to various things like misconfigured settings, corrupt system files, and more there is no way to present one simple solution that will solve everything in one click.
Therefore we are presenting a couple of solutions that will fix your issue, it is advisable to follow them as presented since they will go from the most common to the more complex one.
The most common fix and one that will actually repair things most of the time is simply running the Windows Update troubleshooter.
If the previous solution did not work we will need to do things manually. Follow the steps as presented in order to reset Windows update components.
Well, that was a lot of typing or copy and pasting line by line followed by ENTER after each one but hopefully, your issue is solved. These provided solutions fixed most users' issues with this error but if for some reason this is not the case for you, move to the next step.
If you are still having 0x800f0905 error after previous attempts do the following:
If for any reason previous solutions have not provided you with the solution we will try to fix the issue by performing system restore.
If for any reason Windows still cannot install the update, try installing it manually.
If nothing worked, reset your Windows 11 to its factory settings to fully repair and reset the whole operating system.
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.EasyPDFCombine is a browser extension by Mindspark Inc. This extension claims to offer users an easy and fast way to combine different PDF documents into a single file for easy access and sharing.
When installed this extension changes your default search engine to MyWay.com, it also hijacks your home page and new tab page, also changing it to search powered by MyWay. While browsing the internet with this extension you will see additional pop-up ads, injected ads in search results, and sponsored content throughout your browsing sessions. This extension has been marked as a Browser Hijacker by several anti-virus programs and it is not recommended to keep on your computer.
In today's modern world many households have internet access, most of the connection nowadays is done via Wi-Fi or wireless but there is a high probability that you have also a few devices connected via cable. There are of course many disadvantages and advantages between cable connection and wireless connection.
The main advantages of a hard cable connection are of course faster speed and stability compared to Wi-Fi. But if we look into the cables themselves there is also a big difference between them. Not all cables are the same and quality as well as speed vary a lot between them. Choosing the right cable is essential in order to make a maximum of your internet and we have some great tips and explanations of what cables do so you can make the right choice and enjoy your full internet potential.
Cheap cables and expensive ones are not the same no matter what everyone tells you. The old proverb you get what you pay is true and more expensive cables will be made from better materials and will have a higher transfer rate.
Quality network cables are separated into different categories with proper markings and when buying one you should always look for these markings on the cables themselves, do not buy cables that do not have markings since they will often provide lower transfer rates or will not be shielded from outside influences resulting in packet drops and instability in a network.
Unless stated, these standards are typically rated at their quoted speeds for a run of around 100 meters (around 330 ft) and use a standard RJ-45 Ethernet connector. Each generation of cable is designed to be compatible with the generations that came before it, so it’s possible (for example) to use a Cat-6a cable with a router that only supports speeds of 1Gbps.
When purchasing higher quality cable you might not be able to choose if you have shielding or not since some standards like Cat-6a, Cat-7, and Cat-8 are always shielded. But if you do not have the need for these and you are satisfied with Cat-5e for example you can choose.
Shielded cables are a little more expensive but they will provide you with a coating that will eliminate interference from outside waves making cables more reliable. Of course, if the cable will go through a room that does not have many radio waves or some other interferences then buying a shielded cable is a waste of money.
Usually, there are two types of connector platings on connectors, silver, and gold, and people usually think that gold is much better but there are major differences between silver and gold platings and truth to be told there is no better one, both are different and should be considered depending on your need.
Silver plating will provide you with faster speed since its conductivity is larger than gold, but gold is slower on the oxidation front so its life span is longer. On the other hand, if your cables are always connecting and disconnecting gold will be first to be scrubbed off from the surface since the gold coating is much thinner.
Overall if you would only connect cable once and have slower internet than cable capacity gold is the way to go, in another case if you would use the cable as always connecting and switching and your internet plan is the same as cable transfer capacity you might want to go with silver one.
Network cables are made from copper, your standard conduction material but even here there are differences in quality and therefore the chance of pocket losses over it. More quality less loss and more stable connection and this will depend on the purity of copper that is used in the cable itself. More purity in copper, more stability, simple as that.
So as you can see, there are a lot of different things that will influence your pick of proper network cable but the overall best advice is to get one that will fit well into your needs and setup. pair it up with your router and your internet plan since just simply buying something that you can not use is really a waste of money.
