One day, you are browsing the internet and click on an innocent-looking link for the latest craze, and boom!
You have opened the door for a virus.
Now your computer is infected.
You realize that there are four other devices also connected to your home network and wonder.
Will they be infected with the virus also?
Can A Virus Spread Through A Network?
No, a virus cannot spread through a network without human intervention.
However, the word “virus” has become a type of generic term for something which makes your computer sick and is commonly used to include other types of malware, some of which can be spread through a network autonomously.
What Is Malware?
Malware is a general term used to describe any software designed to cause harm.
Software is just a fancy word for lines of code that are compiled to perform a function.
Malicious software is designed to disrupt the functionality of, steal information from, gain access to, or restrict access on the host device.
Malware can enter a system through emails, removable devices such as USBs or SD cards, hidden inside other programs, infected websites, or through other malware.
This type of malicious software comes in many forms, each with its own unique traits.
Commonly known malware includes viruses, worms, ransomware, rootkits, keyloggers, adware, spyware, bots, and trojans.
Virus: What Is It And How Does It Spread?
A virus is a malicious code that attaches to legitimate code for delivery.
Once delivered, it can spread throughout the infected device, replicating itself and infecting or attaching to other files on the infected system.
Each virus must have a host for delivery to the target device.
This host can be an email, a file, a music download, a website, or a program.
The key aspect of a virus is the method by which it infects a device.
A virus must have user intervention to infect a device.
This means that you must click on the infected portion of the program or file to activate the virus.
The virus must be let in.
It cannot get into the device on its own.
If the infected portion of the file is not activated, it cannot infect the host.
This property of a virus is the key reason why a virus cannot spread through a network autonomously.
How Can A Virus Spread Through A Network?
Now that we have established that a virus cannot spread on its own, how can a virus spread through a network?
Once a device is infected with a virus, the virus can replicate itself and attach to other files on the device.
To spread the virus through the network, the infected device would have to share the infected files or programs with other devices on the network.
However, even if the file or program is shared to other devices on the network, the new devices will not be infected until the virus is activated by user intervention such as opening the infected file or clicking on the link in the infected email.
Another way a virus can spread through the network is by attaching itself to a removable media device such as a USB memory stick.
The virus is now safely on the USB memory stick and will be downloaded to other devices when the USB is inserted and opened on a new device.
Worm: What Is It And How Does It Spread?
A worm is a form of malware that does not require a host to infect a system.
It can be controlled remotely, unlike a virus, and is designed to self-propagate and slow computer function, eat resources, send information out of the device, restrict access to files, or install other types of malware onto the victim machine.
The worm initially enters a device through the same channels as viruses through links, attachments, and infected websites.
Worms can also be directly fed into a system through vulnerabilities in the system itself by hackers.
A vulnerability is a weak spot in the software on the system.
Vulnerabilities can be used by hackers to gain access to a system.
How Can A Worm Spread Through A Network?
A worm can spread through a network autonomously.
Once a worm is introduced into a device on a network, it begins to seek out weak spots in the network by probing for accessible and vulnerable devices also on the network.
Unlike a virus, a worm can enter another device on a network without user intervention.
The worm is designed to seek out ways to enter connected devices and automatically infect those devices.
Through this method of probe and replicate, the worm can grow and infect an entire network by itself.
Malware Infection Signs
Malware can affect your device in numerous ways and may leave signs of infection.
- Excessive pop-up ads and windows. Some types of malware, such as adware, can cause pop-up ads to appear more frequently. New windows may appear on their own or you may be redirected to a site other than the one you were attempting to visit.
- Slowed performance. Many types of malware, such as viruses and worms, can affect the functionality of your device by using up space on your computer or causing numerous processes to run simultaneously.
- Slowed internet connection speed. Malware that is designed to export information such as spyware and worms, can reduce the speed of your internet connection by using up bandwidth. Also, some malware can turn your device into a bot, a slave computer that can be used to target other devices in denial-of-service attacks. The controller of the bot can make your computer send thousands of requests to another target, using up all of your available bandwidth.
- Inability to access your files. Ransomware is a type of malware which locks you out of your files, typically through encryption, and demands payment in return for the decryption key to unlock your files. Ransomware is basically computer extortion.
- Increased data usage when you aren’t using your device. Malware can increase your data usage, especially if the device is being used as a bot or if large amounts of data are being exported or extracted from your device.
- Increased crashes or blue screens. Malware, such as a virus, is usually designed to cause carnage on your system. Viruses and deleted files and corrupt files can cause chaos within the operating system. This chaos can manifest as crashes, blue screens, or error messages.
- Downloads, programs, or applications you did not install. Another kind of malware, such as a Trojan, is designed to install additional programs onto an infected device. A trojan accomplishes this by hiding behind something legitimate like the Greeks did with the Trojan Horse, hence the name Trojan. You think you are downloading a simple game when, in reality, additional programs are being installed along with the desired program.
- Your contacts are receiving emails from you that you did not send. Malware, such as some worms and viruses, can be designed to create and send infected email messages to your contacts. These email messages will appear to come from you but will contain infected links which, when clicked on, will spread the malware to the recipient device.
- Excessively noisy device, even when you are not using it. Excessive noise coming from your device even when it is idle can be a sign that numerous processes are going on without your knowledge. The excessive amount of malicious activity running on your device can cause your computer to run constantly and at a high level, resulting in an overworked system and noise.
If you think your device may be infected with a virus or other malware, the first step to take is to disconnect your device from the internet and your network.
This will isolate the device to prevent spreading the malware to other devices on the network as well as prevent further loss of data or access to the system if it is communicating with another location.
Next, restart your computer in safe mode.
Safe mode allows only the programs necessary for system functionality to run, which will allow you to scan and delete suspicious files more easily.
Once in safe mode, run a full system scan using an antimalware program.
This will scan every bit of data on your system and identify any potential threats it finds.
The antimalware program will list the potential threats and give options of actions to take such as ignore, quarantine, or remove.
Another technique that you can try is to delete all the temporary files or cache from the device.
This may work if you catch the malware early enough.
If either of these methods does not remedy the situation, you can do a system restore to a known uninfected backup point.
The key to this process is to make sure that you are consistently backing up your device to prevent as little loss of information as possible.
If all these options are exhausted and the device is still infected, you may have to reinstall the operating system completely.
This can usually be done by restoring the device to factory condition.
This process essentially provides a clean slate for the device, removing all programs and software installed, including the malware, and only reinstalling the original factory settings.
While there is no single definitive way to protect your device from malware, there are best practices that can be applied to reduce the likelihood of infection.
- Install a robust antimalware solution. Antimalware is software designed to prevent, detect, and remove malware. Antimalware evaluates your entire system as well as incoming data for malware and suspicious activity.
- Use a firewall. A firewall is a program, either hardware or software, which sits between the outside world and your device. A firewall scans all the data which is trying to access your device for suspicious material and blocks that data from entering your device. A firewall should be placed on all devices connected to your network to prevent malware from spreading through the network.
- Change your default router password. Routers are devices which direct the traffic of information within a network. Routers typically come set with a default password for easy access when setting up the device.
These default passwords are common knowledge and can be used to access and infect your network. Always change the default password to a complex password to protect your network. In fact, if any device comes with a preset default password, a good rule of thumb is to always change the default password.
- Avoid public Wi-Fi. Instead, use a personal hotspot, or if you must use public Wi-Fi, use a VPN for internet access. A VPN, or virtual private network, creates a private, secure, and encrypted connection for access to the internet, regardless of whether the Wi-Fi is public or private. VPNs prevent eavesdropping from other devices connected to the same Wi-Fi network.
- Keep the operating system and programs updated. Updates to operating systems and programs are key to keeping them safe. As new exploits, vulnerabilities, and malware is discovered, software companies issue updates or patches to fix the discovered exploit or vulnerability.
Antimalware updates keep the software current with the latest malware threats. Many operating systems, programs, and antimalware have the option to auto-update when new patches and updates are released. Turn this function on and do not put off updating your system.
- Do not click on suspicious links. Suspicious links may be sent via email, SMS, direct message, or on websites and pop-ups. Only click on links you are certain are authentic. For example, chances are you are not related to a foreign prince, your phone bill was not paid for you, and you do not need to act now because your computer is infected.
- Only access banking or other websites containing sensitive information through their official site. Phishing emails, emails that are designed to trick a user into clicking on a link to steal information or install malware, often use reputable entities such as banks, credit card companies, or the IRS to entice or scare people into clicking on an embedded link in the email.
If you receive an email from an entity that you use, such as your bank, telling you that you need to click on a link for any reason, do not click the link. Instead, go directly to the official website of the entity and log in from there. If the email is legitimate, you will be able to access the information from the official website. (Side note: The IRS will not email or call you directly. The IRS only contacts individuals through the services of the United States Postal Service [snail mail].)
- Only download from reputable sites. Avoid downloading games, music, movies, files, or programs from unknown or suspicious sites.
- Back up your device regularly. Creating a backup is essentially taking a snapshot of your device at a specific point in time. This backup can be used as a reload point if your device becomes infected. By regularly backing up your device, you reduce the amount of data that would be lost if you needed to restore your device to a previous point before infection.
Antivirus Or Antimalware
Previously, the majority of computer threats came in the form of viruses.
Due to this fact, software was developed to target the most common cause of computer sickness, the virus.
Hence, antivirus software.
Antivirus software was designed to recognize previously detected viruses through signature-based detection.
With the constant evolution of cyber threats, strictly signature-based protection such as antivirus software became inefficient at protecting against emerging threats since it had to be constantly updated to include the signatures of newly identified viruses.
However, today, most antivirus programs are designed to function like antimalware.
Antimalware is designed to prevent, detect, and remove all types of malware, including viruses.
This type of software uses signature-based detection, heuristic-based detection, AI/ML-based detection, and sandboxing to identify potential malware threats.
Any known malware threats can be identified by their signature, or unique identifier, through signature-based detection just like traditional antivirus software used.
Known threat signatures are uploaded to extensive databases which antimalware software can use to identify these threats.
To identify zero-day, or unknown malware, heuristic-based techniques may be used.
Heuristic-based detection evaluates the behavior of software to decide if it is potential malware.
If a program is behaving suspiciously, it is flagged as malware.
AI/ML, or artificial intelligence/machine learning-based detection uses heuristic-based techniques but combines them with AI/ML to learn how your device as a whole behaves.
This constant learning enables antimalware to better predict which pieces of data are suspicious.
Sandboxing is the process of placing software into an enclosed environment to observe its behavior before allowing it into the main computer.
This is a way for the antimalware to test the validity of the program before allowing it access to the main computer environment.
Today, antivirus and antimalware software offered by reputable providers are fundamentally the same.
Antivirus software is no longer restricted to only virus detection but is designed to use the same methods of detection as antimalware uses to detect, prevent, and eliminate malware.
The term antivirus, however, has continued to be used over antimalware due to the familiarity the general public has with the term virus.
Just like the question, can a virus spread through the network, it is a matter of semantics.
Virus and antivirus have become the accepted blanket terms for computer infection and prevention, even though malware and antimalware are actually more appropriate terms.
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