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.
Visual studio code is a code editor available for Windows, Linux, and macOS. It is a completely free tool offering you to code in any language without the need to switch to another editor.
Visual Studio Code is part of Microsoft Visual Studio which is a complete integrated development environment (IDE). Take notice that Visual studio itself has more advanced tools for developing and testing, it has 24/7 support, training, and Azure for WEB apps.
Visual Studio Code is an editor lacking in some advanced features Visual Studio offers.
net stop wuauserv net start cryptSvc net start bits net start msiserver
net start wuauserv net start cryptSvc net start bits net start msiserver
Some Windows 7 and Windows 8.1 users reported experiencing a Compare Exchange128 error when trying to upgrade to Windows 10. The error reads, “You can’t install Windows 10 because your processor doesn’t support CompareExchange128”. In order to upgrade to Windows 10 (64-bit), the CMPXCHG16B instruction must be present. If you receive this error, this mostly means that your CPU doesn’t have the CMPXCHG16B instruction.
Error CausesThe CompareExchange128 error normally occurs due to two possible reasons:
One main requirement to upgrade to Windows 10 is for your CPU to have the CMPXCHG16b instruction. You also need the right BIOS version to guarantee a smooth installation. See below on how to manually fix this issue.
NOTE: If you don’t feel confident using the manual methods listed below, it’s highly advisable to get help from an expert technician. If you don’t know someone, you can also use an automated tool to fix this.
Before performing any fixes, try to determine first if the cause of the error is due to your CPU lacking the CMPXCHG16b instruction. You can use a CPU Info tool that provides complete details about your processor, memory, and motherboard. If you’re looking for more in-depth information, you might also try command-line utilities. But, the safest and easiest way to check this is by simply searching online. Try using the search query: <CPU Model> CMPXCHG16b
This method will download the latest BIOS from your motherboard’s manufacturer. This makes sure your CPU has the CMPXCHG16b instruction needed to complete the Windows 10 64-bit installation. To update your computer’s BIOS, complete the following steps:
If updating the BIOS doesn’t work, what you can do is install a 32-bit version of Windows 10 instead of the 64-bit version. Here’s how to do this:
If the above two methods don’t work, there’s a great chance that this error occurs because of an outdated processor/motherboard. Your next possible solution is to buy an updated model that’s fully compatible with 64-bit Windows 10.
If all else fails, you might want to consider using this powerful automated tool to quickly fix the problem and any other computer-related issues.
Error code 0xc000021a occurs when the system is unable to start or there’s a failure in critical system processes. Normally, it would take about several seconds for the system to boot and while on the startup process, error code 0xc000021a may take place to block the system to boot up. Users will get a blue screen of death (BOSD) when this error occurs. When upgrading to Windows 10, be careful; you might encounter other error messages such as error code 8007002c.
Error CausesThere are several reasons why error code 0xc000021a occurs. It is important to have a full understanding of what caused the blue screen of death before attempting to fix the error by yourself. See below for a few common causes:
• Computer malware has infiltrated your device.
• Important files such as Winlogon.exe and Csrss.exe are damaged. Winlogon.exe file is responsible for handling the login and logout processes while Csrss.exe is a vital part of Microsoft Client or Server ‘Runtime Server Subsystem’. Once one of these files is damaged or deleted, a stop error will occur.
• When there are mismatched system files installed or system upgrading process failed or still incomplete.
• Premature unloading of Wbemprox.dll
• Newly installed third-party software is not compatible with the operating system.
• There are corrupted, outdated, or incorrectly configured device drivers.
• There’s insufficient space in the system partition. Once the system partition is full, certain errors such as error code 0xc000021a will manifest.
• Windows registry is corrupted or damaged due to a software or system change. This means there are registry entries that are not cleared after uninstalling an application.
In fixing error code 0xc000021a, you might want to try and manually do so. Manual repair methods can give users effective and efficient solutions, addressing the root problems in relation to Windows error codes. Once the manual repair method is correctly implemented, users will be able to resolve issues immediately. However, there might be instances when a Windows professional is needed. In such cases, seek help from a certified Windows expert or you might want to consider using an automated tool whenever necessary.
As more and more people get into insider preview of upcoming Windows 11 we will see more and more different takes and opinions on it.
Generally speaking, the first wave was quite positive when it was previewed but how time is passing more and more limitations and frustration comes to the surface.
Some of the limitation that is inside it, which have been confirmed by Microsoft itself includes features missing that we had in Windows 10 like moving the application to the taskbar in order to pin it, moving the file in the taskbar to open it in default application and some big annoyances like Windows opening widgets always in Edge no matter what is your default browser. Not being able to move the taskbar from the bottom is also one of many illogical things.
There is not really a point in these missing features since they were working fine in Windows 10 and many users liked them since they could customize Windows more to their liking, now with this new look at limitations it reminds me personally much of apple macOS and I will be honest, I am not a big fan of that kind of thinking.
If I wanted that kind of OS I would have gotten myself a MAC, not custom build PC, but hey, Linux is always a free alternative, and how Microsoft itself is pushing limitations and in my opinion bad design choices along with awful system requirements that might just be a case for a lot of users.
I am really not sure what is logic behind these moves and I am sure they have their reasons but this time it seems that their take on the new OS is not resonating well with the overall user population, well at least what I have heard so far. Things of course can still be changed and made for the better and I would rather see release postponed and issues addressed than getting more system hogging and limited new OS that at its current state looks like reskinned Windows 10 with limitations. “Windows could not start the service on Local Computer. Error 1079: The account specified for this service differs from the account specified for other services running in the same process.”If you got the error message above, then here’s how you can fix it:
Desk 365 is a program developed by 337 Technology Limited and is classified as a potentially unwanted application by a number of Antiviruses. While not technically malware, for many users it is unwanted as it is often distributed as a bundle with other downloads. It allows a fast way to access your shortcuts and applications. Upon installation this program will insert itself into the system registry, adding startup strings to allow it to automatically start every time your system is restarted. The software adds a scheduled windows task to allow it to reopen itself even when closed. The applications also access the internet and add firewall rules to your system, that allow it to access anything without restrictions.
The main executable file for this application is Dock365.exe. It is possible to delete this file preventing the application to run, but its monitoring services and registry entities remain hidden inside your computer.
The software sends browsing information back to its ad servers, displaying custom ads and sponsored products instead of the usual search results. And the app itself pins itself to the start menu and cannot be removed.
You probably heard about switches for LAN but not a lot of people heard about KVM switches. So what exactly is KVM switch?
If we look at the name, it is a shortcut for Keyboard, Video & Mouse and the original idea was to have multiple computers but one keyboard, mouse, and monitor. These peripherals would be connected to the KVM switch and other computers could all use one set of these on the fly when needed.
The technology behind the switch is a little interesting since it will actively fake signals to other computers that are not using peripherals. Once they are switched to them the transition is smooth and not noticeable. In old days these switches were more important than today since on every mouse or keyboard disconnection you had to reboot the computer, and although today that is not the case CPU will still detect disconnection and on the next connection it will run through the ID of the device and try to use the existing driver and if peripheral was connected in other USB port, it will install the same driver but connect it to the new USB port.
This type of reconnection can slow down work and place unnecessary load on the CPU so that is why KVM will fake connection in order to make switching externals on the computer smooth and in nick of a time.
These days modern KVM switches will offer you more options than just being able to switch between keyboard, mouse, and monitor. Modern switches now offer Lan, audio, and many more various options.
There are also different kinds of switches offering you only one option, like for example just a Video switch that will let you use one monitor on three computers and many more other specialized options.
So far we talked about Hardware switches, a real device being able to take peripherals into it and switch computers on the fly. On the other line, we have software switch solutions that will have specific software installed on all computers and have it run at all times, and switching between them will be through specific software.
There are two very good and main advantages of using software solutions instead of a hardware one. First, of course, is the price, since the most popular Synergy is an open-source solution, completely free of charge. The second big advantage is that software switch is not limited to how many computers can you use. Hardware switches tend to go to a large number like 16 but if you have a large cluster of computers over a LAN, let's say 30 then the box solution might be difficult.
On the other hand software solution will switch only keyboard and mouse since each other computer will have to have some screen on it in order to work. Both solutions have their strong advantages and disadvantages and it is up to you to choose one that best suits you.
If you are multitasking with a lot of computers or just need your peripherals from time to time to connect to another machine then the KVM switch is something that you might find the use of. Just be aware that if you go for some cheap switch you might experience some lag on your peripherals, but if that is not a concern you can get hardware one for as low as $50 USD.
