A virus is a piece of code that inserts itself into an application and executes when the app is run, allowing it to steal data, launch attacks, or conduct ransomware attacks. Viruses require an infected application to run but worms can operate independently. Computer viruses and worms are often spread through email attachments and downloads and exploit vulnerabilities in software and security settings. Antivirus software, firewalls, updating systems regularly, and caution about suspicious files and emails can help prevent infection.

1. VIRUSES
• A virus is a piece of code that inserts itself into an application and executes
when the app is run. Once inside a network, a virus may be used to steal
sensitive data, launch DDoS attacks or conduct ransomware attacks.
• A virus cannot execute or reproduce unless the app it has infected is running.
This dependence on a host application makes viruses different from trojans,
which require users to download them, and worms, which do not use
applications to execute. Many instances of malware fit into multiple
categories: for instance, Stuxnet is a worm, a virus and a rootkit.
• Computer viruses require human action to infect computers and mobile
devices and are often spread through email attachments and internet
downloads.

2. What does a computer virus do?
• Some computer viruses are programmed to harm your computer by damaging
programs, deleting files, or reformatting the hard drive. Others simply
replicate themselves or flood a network with traffic, making it impossible to
perform any internet activity. Even less harmful computer viruses can
significantly disrupt your system’s performance, sapping computer memory
and causing frequent computer crashes.
How does a computer get a virus?
• Sharing music, files, or photos with other users
• Visiting an infected website
• Opening spam email or an email attachment
• Downloading free games, toolbars, media players and other system utilities
• Installing mainstream software applications without thoroughly reading
license agreements

3. Computer virus protection
• Use antivirus protection and a firewall
• Get antispyware software
• Always keep your antivirus protection and antispyware software up-to-date
• Update your operating system regularly
• Increase your browser security settings
• Avoid questionable Websites
• Only download software from sites you trust.
• Carefully evaluate free software and file-sharing applications before
downloading them.
• Don't open messages from unknown senders

4. NETWORK WORMS
• A worm virus refers to a malicious program that replicates itself, automatically
spreading through a network. In this definition of computer worms, the worm
virus exploits vulnerabilities in your security software to steal sensitive
information, install backdoors that can be used to access the system, corrupt
files, and do other kinds of harm.
• Worms consume large volumes of memory, as well as bandwidth. This results in
servers, individual systems, and networks getting overloaded and
malfunctioning. A worm is different from a virus, however, because a worm can
operate on its own while a virus needs a host computer.
• To get a worm in a computer, the worm is often transmitted through
vulnerabilities in software. They could also be sent through email attachments
or within instant messages or spam emails. After a file is opened, it may link the
user to a malicious website or it could download the worm to the user’s device
automatically. After the worm is on the device, it infects it without the user
being able to tell.

5. How a Worm Spreads
A computer worm takes advantage of system vulnerabilities to accelerate its
spread. It can jump from one device to another through different means, be that
an email attachment, malicious link, or local area network (LAN). Here are the
most common ways a computer worm spreads:
The internet: Most devices connect to the internet via a network, which is a
convenient superhighway for computer worms to spread. Once a worm
infiltrates a device, it can spread to other devices throughout the LAN.
Emails: Have you ever received a suspicious email with a link or an attachment
from a stranger? That’s how some hackers spread malware, including worms.
There are also worms that can make email programs such as Outlook send
emails containing the malware to contacts autonomously.
File-sharing platforms: Unless you know where it’s from, there’s really no
way to tell if the file you’re downloading from a peer-to-peer file sharing
platform contains malware. That’s why worms spread easily through such
platforms.
Smartphones: Smartphones are ideal worm carriers because we tend to
connect our phones to multiple Wi-Fi networks, which could accelerate the
spread of worms.
Removable drives: A flash drive or a removable hard drive can get infected if
plugged into an infected computer. Subsequently, infected removable drives can
spread the worm when they are connected to different computers.

6. How to Prevent and Get Rid of Computer Worms
On-access scans: Antivirus tools with this feature actively scan your device in
the background to detect and prevent the spread of worms. Since computer
worms self-replicate without human interaction, having your antivirus protect
your device continuously is ideal.
Email scans: The scope of an antivirus’s malware scan includes your email
sometimes. When you open an email that has a link or attachment, the antivirus
scans it first and notifies you if it’s safe to open.
Firewall: Given the ability of computer worms to spread through networks,
an antivirus with a built-in firewall is ideal. If there’s an infected device in your
network, the firewall prevents the worm from entering your other devices.