Is your computer acting weird? Are boxes popping up on your screen, telling you your computer is infected? Are you hearing strange sounds? Your computer may have been infected with malware or a virus.
It’s not always easy to determine whether your computer has become infected with a virus, worm, Trojan or spyware; authors of malicious software do their best to disguise their work. However, you can look out for certain signs that your computer is infected.
Definition of Computer Virus
A computer virus is a type of malware that attaches to another program (like a document), which can replicate and spread after a person first runs it on their system. For instance, you could receive an email with a malicious attachment, open the file unknowingly, and then the computer virus runs on your computer. Viruses are harmful and can destroy data, slow down system resources, and log keystrokes.
Cybercriminals aren’t creating new viruses all the time, instead, they focus their efforts on more sophisticated and lucrative threats. When people talk about “getting a virus” on their computer, they usually mean some form of malware it could be a virus, computer worm, Trojan, ransomware or some other harmful thing. Viruses and malware continue to evolve, and often cybercriminals use the type that gives them the best return at that particular time.
Computer Virus vs. Malware
The terms “virus” and “malware” are often used interchangeably, but they’re not the same thing. While a computer virus is a type of malware, not all malware are computer viruses.
The easiest way to differentiate computer viruses from other forms of malware is to think about viruses in biological terms. Take the flu virus, for example. The flu requires some kind of interaction between two people like a handshake, a kiss, or touching something an infected person touched. Once the flu virus gets inside a person’s system it attaches to healthy human cells, using those cells to create more viral cells.
A computer virus works in much the same way:
- A computer virus requires a host program.
- A computer virus requires user action to transmit from one system to another.
- A computer virus attaches bits of its own malicious code to other files or replaces files outright with copies of itself.
It’s that second virus trait that tends to confuse people. Viruses can’t spread without some sort of action from a user, like opening up an infected Word document. Worms, on the other hand, are able to spread across systems and networks on their own, making them much more prevalent and dangerous.
Famously, the 2017 WannaCry ransomware worm spread around the world, took down thousands of Windows systems, and raked in an appreciable amount of untraceable Bitcoin ransom payments for the alleged North Korean attackers.
Computer viruses don’t typically capture headlines like that—at least not anymore. They are still a harmful type of malware, but they are not the only type of threat out there today, on your computer or mobile device.
What is a worm?
A worm is computer code that spreads without user interaction. Most worms begin as email attachments that infect a computer when they’re opened. The worm scans the infected computer for files, such as address books or temporary webpages, that contain email addresses. The worm uses the addresses to send infected email messages and frequently mimics (or spoofs) the “From” addresses in later email messages so that those infected messages seem to be from someone you know. Worms then spread automatically through email messages, networks, or operating system vulnerabilities, frequently overwhelming those systems before the cause is known. Worms aren’t always destructive to computers, but they usually cause computer and network performance and stability problems.
What is a trojan horse?
A trojan horse is a malicious software program that hides inside other programs. It enters a computer hidden inside a legitimate program, such as a screen saver. Then it puts code into the operating system that enables a hacker to access the infected computer. Trojan horses do not usually spread by themselves. They are spread by viruses, worms, or downloaded software.
What is spyware?
Spyware can install on your computer without your knowledge. These programs can change your computer’s configuration or collect advertising data and personal information. Spyware can track Internet search habits and can also redirect your web browser to a different website than you intend to go to.
How do I prevent a computer virus?
Preventing computer viruses from infecting your computer starts with situational awareness.
“As it applies to cybersecurity, situational awareness is your first line of defence against cyberthreats. 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.
If an email reads oddly, it’s probably a phishing scam or malspam. When in doubt about the authenticity of an email, don’t be afraid to reach out to the sender. A simple call or text message can save you a lot of trouble.
Next, invest in good cybersecurity software. We’ve made a distinction between computer viruses and malware, which now begs the question, “Do I need antivirus software or anti-malware software?”.
Antivirus (AV) refers to early forms of cybersecurity software focused on stopping computer viruses. Just viruses. Anti-malware refers to all-encompassing threat protection designed to stop old-fashioned viruses as well as today’s malware threats. Given a choice between traditional AV with limited threat detection technology and modern anti-malware with all the bells and whistles, invest in anti-malware and rest easy at night.
As mentioned previously in this piece, traditional AV solutions rely on signature-based detection. AV scans your computer and compares each and every file against a database of known viruses that functions a lot like a criminal database. If there’s a signature match, the malicious file is thrown into virus jail before it can cause any damage.
The problem with signature-based detection is that it can’t stop what’s known as a zero-day virus; that is, a virus that cybersecurity researchers have never seen before and for which there is no criminal profile. Until the zero-day virus is added to the database, traditional AV can’t detect it.
If it looks like a virus and behaves like a virus, then it’s probably a virus.
Don’t be tricked into downloading malware
Here are some tips that can help protect you from downloading software that you don’t want:
- Only download programs from sites that you trust. If you’re not sure whether to trust a program that you want to download, enter the name of the program into your favorite search engine to see whether anyone else has reported that it contains spyware.
- Read all security warnings, license agreements, and privacy statements that are associated with any software that you download.
- Never click “Agree” or “OK” to close a window that you suspect might be spyware. Instead, click the red “x” in the corner of the window or press Alt + F4 on your keyboard to close a window.
- Be wary of popular “free” music and movie file-sharing programs, and make sure that you understand all the software packaged with those programs.
- Use a standard user account instead of an administrator account. An administrator account can access anything on the system, and any malware run with an administrator account can use the administrator permissions to potentially infect or damage any files on the system.
How to deal with a computer virus or malware
When it comes to preventing computer viruses or malware infections, you should always be proactive. The following best practices are just some ways you can work to make sure your computer remains free of malware and viruses.
Maintain your installed programs.
One of the main ways viruses gain access to a system is through security lapses in existing software. Therefore, as the first step to prevent your computer from getting infected in the first place, you should make sure your applications, antivirus software and operating system are up to date. This is doubly important when it comes to your operating system since Apple, Microsoft and other providers regularly release security patches to deal with potential weaknesses. You can also reduce the number of potential vulnerabilities for cybercriminals to exploit by uninstalling applications you don’t use.
Only install one antivirus solution.
It may seem wise to have multiple layers of antivirus protection on your computer, but this is a case of “less is more.” If you have more than one antivirus software program installed on your machine, you run the risk of them cancelling each other out because each thinks the other is a virus. This can result in limited antivirus protection at best, file corruption at worst.
Automate virus scans.
You don’t always have to be beside your computer when it conducts a virus scan. Most modern antivirus software has automation features that let you set a specific time for the computer to conduct its virus scan. By setting the process for a time where you don’t need to use the computer – like when you’re sleeping – you can make sure your system is safe without it hindering your productivity.
Pop those pop-ups.
If you’re dealing with rogue pop-ups on your computer, you can take these steps to address them, according to Kaspersky:
- Go into the Task Manager and stop the process that’s running the pop-up.
- Windows users can hit the Ctrl, Alt and Delete keys at the same time to find the Task Manager quickly.
- Mac users can go to the Apple menu on the top left and select Force Quit to find it.
- Note that this doesn’t remove the infection.
- Next, you should install and/or run antivirus software to fix the problem, if possible.
Restart your computer in safe mode.
Starting your computer in safe mode gives you a chance to run your antivirus software and take a closer look at what the issue may be. Begin by rebooting the computer. On a Windows PC, press and hold F8 as soon as the reboot begins. Then, choose safe mode from the menu that appears. On a Mac, hold down the Shift key while rebooting. Then, perform an antivirus scan to eliminate any other potential infections.
How do I remove a computer virus?
Going back to our virus analogy one final time, removing a virus from your body requires a healthy immune system. Same for your computer. A good anti-malware program is like having a healthy immune system. As your immune system moves through your body looking for and killing off invading viral cells, anti-malware scans for files and malicious code that don’t belong on your system and gets rid of them.
The FREE version of Malwarebytes is a good place to start if you know or suspect your computer has a virus. Available for Windows and Mac, the free version of Malwarebytes will scan for malware infections and clean them up after the fact. Get a free premium trial of Malwarebytes for Windows or Malwarebytes for Mac to stop infections before they start.
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