Two sources of computer viruses

Source: Shutterstock Well, in malware was a bit of a myth. MyDoom MyDoom is considered to be the most damaging virus ever released—and with a name like MyDoom would you expect anything less? Tip: never open a link in an email unless you know exactly what it is. Cost of the malware: An exact cost is yet to be calculated. Slammer While most of the malware on this list strictly hit computers, Slammer was created with broader ambitions.

Source: Stocksnap 8. Stuxnet Stuxnet is easily the scariest virus on the list as it was built by government engineers in the US with the intention of obstructing nukes from being built in Iran. Yes, you read that right. Who needs to target email when they can gun for nukes? Cost of the malware: Unknown. Opt-in to Cyber Safety. Read all reviews. Watch the TV ad. Norton Deluxe. Learn More.

Price subject to change. Subscription details below. Norton Secure VPN. Connect to Wi-Fi at home and on-the-go with the reassurance of bank-grade data encryption. Android and iOS are susceptible to various forms of malware, too. Fortunately, most cybersecurity companies like Malwarebytes offer protection for Windows, Mac, Android, and iOS today. What fun! Is a Trojan a virus? Trojans can be viruses. A Trojan could be a seemingly benign file downloaded off the web or a Word doc attached to an email.

Think that movie you downloaded from your favorite P2P sharing site is safe? Think twice, because they could contain a virus. Is a worm a virus? Worms are not viruses, though the terms are sometimes used interchangeably. Even worse, the terms are sometimes used together in a strange and contradictory word salad; i. As mentioned earlier, a virus needs a host system to replicate and some sort of action from a user to spread from one system to the next.

Once on a system, worms are known to drop malware often ransomware or open a backdoor. Is ransomware a virus? Ransomware can be a virus. In fact, the very first ransomware was a virus more on that later.

Nowadays, most ransomware comes as a result of computer worm, capable of spreading from one system to the next and across networks without user action e. Is a rootkit a virus? Rootkits are not viruses. Is a software bug a virus? Software bugs are not viruses. A software bug refers to a flaw or mistake in the computer code that a given software program is made up of.

Software bugs can cause programs to behave in ways the software manufacturer never intended. The Y2K bug famously caused programs to display the wrong date, because the programs could only manage dates through the year After the year rolled over like the odometer on an old car to While the Y2K bug was relatively harmless, some software bugs can pose a serious threat to consumers.

Cybercriminals can take advantage of bugs in order to gain unauthorized access to a system for the purposes of dropping malware, stealing private information, or opening up a backdoor. This is known as an exploit. Preventing computer viruses from infecting your computer starts with situational awareness. By staying on the lookout for phishing attacks and avoiding suspicious links and attachments, consumers can largely avoid most malware threats. Regarding email attachments and embedded links, even if the sender is someone you know: viruses have been known to hijack Outlook contact lists on infected computers and send virus laden attachments to friends, family and coworkers, the Melissa virus being a perfect example.

A simple call or text message can save you a lot of trouble. Next, invest in good cybersecurity software. Antivirus AV refers to early forms of cybersecurity software focused on stopping computer viruses. Just viruses. Your usual homepage may change to another website, for instance. Plus, you may be unable to reset it. Mass emails being sent from your email account. A criminal may take control of your account or send emails in your name from another infected computer.

Frequent crashes. A virus can inflict major damage on your hard drive. This may cause your device to freeze or crash. It may also prevent your device from coming back on. Unusually slow computer performance.

A sudden change of processing speed could signal that your computer has a virus. Unknown programs that start up when you turn on your computer. You may become aware of the unfamiliar program when you start your computer. Unusual activities like password changes. This could prevent you from logging into your computer. How to help protect against computer viruses?

How can you help protect your devices against computer viruses? Here are some of the things you can do to help keep your computer safe.

What are the different types of computer viruses? Boot sector virus This type of virus can take control when you start — or boot — your computer. Web scripting virus This type of virus exploits the code of web browsers and web pages. Direct action virus This type of virus comes into action when you execute a file containing a virus. Polymorphic virus A polymorphic virus changes its code each time an infected file is executed.

File infector virus This common virus inserts malicious code into executable files — files used to perform certain functions or operations on a system.

Multipartite virus This kind of virus infects and spreads in multiple ways. Macro virus Macro viruses are written in the same macro language used for software applications. How to remove computer viruses You can take two approaches to removing a computer virus. Separately, Norton also offers a free, three-step virus clean-up plan. Once a virus is installed on your computer, the process of removing it is similar to that of removing any other kind of malware — but that isn't easy. CSO has information on how to remove or otherwise recover from rootkits , ransomware , and cryptojacking.

We also have a guide to auditing your Windows registry to figure out how to move forward. If you're looking for tools for cleansing your system, Tech Radar has a good roundup of free offerings , which contains some familiar names from the antivirus world along with newcomers like Malwarebytes. And it's a smart move is to always make backups of your files , so that if need be you can recover from a known safe state rather than attempting to extricate virus code from your boot record or pay a ransom to sketchy Eastern European gangsters.

The first true computer virus was Elk Cloner , developed in by fifteen-year-old Richard Skrenta as a prank. Elk Cloner was an Apple II boot sector virus that could jump from floppy to floppy on computers that had two floppy drives as many did.

Every 50th time an infected game was started, it would display a poem announcing the infection. But most of the big-name malware you've heard of in the 21st century has, strictly speaking, been worms or Trojans, not viruses.

That doesn't mean viruses aren't out there, however — so be careful what code you execute. Here are the latest Insider stories. More Insider Sign Out. Sign In Register. Sign Out Sign In Register. Latest Insider. Check out the latest Insider stories here. More from the IDG Network.

What is a computer virus? Computer virus definition A computer virus is a form of malicious software that piggybacks onto legitimate application code in order to spread and reproduce itself.