The first computer worm to spread extensively across the internet was the Morris Worm, released on November 2, 1988.
This computer worm was created by Robert Tappan Morris, a graduate student at Cornell University, it was originally designed as an experiment to gauge the size of the early internet. However, a design flaw caused it to replicate much faster than intended, leading to the first major cyberattack in history.
Within 24 hours, it infected approximately 6,000 computers, which was about 10% of the internet at the time. It exploited vulnerabilities in the Unix operating system, specifically in programs like sendmail and the finger service. The worm didn’t delete data, but it reinfected machines multiple times, consuming so much processing power that it caused systems to crash or become unusable.
SO WHAT IS A COMPUTER WORM?
A computer worm or digital worm is a standalone malware computer program designed to replicate itself and spread across networks without requiring human interaction.
However, unlike computer viruses, these digital worms don’t require a host file or program to latch onto. Instead, they exist as self-contained files or scripts.
While both are types of malicious software (malware) that replicate themselves and damage computer systems, the main difference is how they spread. Computer viruses require a “host” and human interaction to spread, whereas computer worms are standalone programs that spread by themselves across networks.
WHAT ARE THE MAIN DIFFERENCES BETWEEN A COMPUTER VIRUS AND A
COMPUTER WORM?
Computer Virus
A computer virus attaches itself to a clean computer program or file (host) and hides there. It stays completely still until a user accidentally opens the infected file or runs the program. Once activated, the virus infects other files and spreads when the user shares those files with others. Computer virus takes time to spread because it relies on human movement.
Computer Worms
A computer worm is a standalone, independent program. It does not need a host file to exist, nor does it need you to click anything. Once a computer worm gets onto your device (often through a network connection or software loophole), it replicates itself and spread automatically. Computer worms spread rapidly through network connections such as the internet and Local Area Network.
Both computer worm and computer virus can harm your device, delete files, or steal personal information.
To keep your devices and data safe while browsing, you don’t need to be a tech expert—you just need to stay alert. Here are the most effective habits to adopt:
1. Check for the “Padlock”
Always look at the address bar for HTTPS (and the padlock icon) before entering any passwords or credit card info. This means your connection is encrypted, making it much harder for hackers to “listen in” on your data.
2. Be Skeptical of Links and Pop-ups
Think before you click: Hover your mouse over a link to see the actual URL destination in the bottom corner of your browser. If it looks gibberish or slightly misspelled (like g00gle.com instead of google.com), stay away.
Avoid “Free” Traps: Sites offering free movie streams or cracked software are prime breeding grounds for the worms and viruses we discussed.
3. Use a Password Manager
Reusing the same password is a huge risk. Use a password manager (like Bitwarden, Google Password Manager or 1Password) to create and store unique, complex passwords for every site. This way, if one site gets hacked, your other accounts stay safe.
4. Enable Two-Factor Authentication (2FA)
Even if a hacker gets your password, 2FA acts as a second lock. Always choose an authenticator app or a security key over SMS (text) codes when possible, as they are more secure.
5. Keep Your Browser Updated
Those “Update Available” pop-ups are actually critical. They often contain security patches for newly discovered vulnerabilities that hackers are already trying to exploit.
6. Use an Ad Blocker
Many malicious scripts (malvertising) are delivered through shady ads. Using an extension like uBlock Origin can stop these scripts from even loading on your page.
TYPES OF COMPUTER WORMS
1) Email Worms
Also called mass-mailer worms, they propagate by sending copies of themselves (whether as email attachments or malicious links). Upon opening the file or clicking on the link, a worm will activate, and it will have access to contacts of the recipient to continue spreading.
2) File-sharing Worms
Since file-sharing worms allow infected users to hide behind the guise of real media files, they are shared in filesharing aids. Once the file is downloaded by a user, the worm turns the device into an evil server that may accumulate personal data or credentials to be used or sold.
3) Crypto Worms
Crypto worms are like ransomware. They spread through systems, encrypt files of users, and then request that decryption key be returned by payment, typically in cryptocurrency. These worms can lock down entire networks if not contained.
4) Internet Worms
This category of Computer Worms has the specific purpose of targeting widely used websites with weak Cyber Security measures. The goal of these worms is to infiltrate the website’s system, which then allows them to spread to any computer that has accessed the site and infect them as well.
5) Instant Messaging Worms
The worms sent by Instant Messaging Worms exploit an instant messaging program and social media by spitting off impersonation links or files sent by a trusted source. They are usually filled with clickbait, making a user unintentionally infect himself or herself and share it with others.
6) IRC Worms
Internet Relay Chat (IRC) Worms spread into chat rooms or forums through the vulnerability of IRC clients. They transmit virulent links or move orders to the people and propagate at high-speed using real-time chats.
7) P2P Worms
P2P Worms take advantage of peer-to-peer file-sharing programs by assuming the form of desirable downloadable content. After being downloaded, they multiply through shared folders and also linked users, so infection becomes widespread even without the knowledge of the user.
Computer Worm Examples
1) Morris (1988)
Created by Robert Morris, this worm unintentionally overloaded 6,000 UNIX Operating Systems leading to crashes and damages up to £8 million.
2) Mydoom (2004)
Targeting Windows systems, Mydoom became one of the fastest-spreading worms, causing an estimated £30 billion in damages. It persists, accounting for a significant portion of malicious emails.
3) Storm Worm (2007)
Storm Worm was carried by emails with eye catching headlines like 230 killed
as storm swept Europe which even fooled the user into clicking. After
activation, it infected systems, making them a botnet to send spam and
attack computers with millions of computers.
4) ILOVEYOU (2000)
ILOVEYOU was a love letter worm which made itself known as a love letter,
also called the Love Bug. It hit more than 50 million devices within two weeks
of its outbreak and resulted in clean-up and recovery costs which amount to
about 12 billion pounds.
5) Conficker
Also referred to as Downup or Kido, Conficker exploited vulnerabilities in
Microsoft Windows to spread rapidly. It infected millions of computers across
more than 100 countries. It disrupted networks worldwide and demonstrated
how unpatched systems can be compromised at a massive scale.
6) Code Red
Code Red was a widespread Computer Worm that emerged in 2001, infecting
more than 300,000 systems. It targeted Microsoft IIS web servers and
generated massive traffic from compromised machines, even overwhelming
high-profile websites such as that of the White House.
How do I know if I have a computer worm?
Computer worms are a type of self-replicating malware. Because they
consume resources and spread without your knowledge, they typically leave
behind specific red flags.
Signs of a Computer Worm Infection
Sudden Performance Drops: Unusually high CPU usage, frequent
freezing, or a sluggish system.
Rapidly Disappearing Hard Drive Space: Because worms replicate
repeatedly, they can eat up large chunks of your storage.
Network Activity Outburst: Your internet becomes incredibly slow, or
you notice unusually high network traffic even when you aren’t
browsing.
Unfamiliar Emails: People in your contact list receive strange or spam
emails that you never sent.
Missing or Strange Files: System files go missing, or you notice
unknown programs/folders suddenly appearing on your hard drive.
Programs Running Automatically: Web browsers or programs
launching on their own without you clicking them.
How to Confirm and Remove the Worm
Disconnect the Network: Unplug your Ethernet cable or turn off Wi-Fi.
This isolates the computer worm so it cannot infect other devices.
Run an Offline Antivirus Scan:
- Windows: Open the Windows Security app, go to Virus & threat
protection > Scan options, and select Microsoft Defender
Antivirus offline scan. The PC will restart and perform a deep,
15-minute scan while the malware is inactive.
- Check Task Manager:
- Press Ctrl + Shift + Esc to open Task Manager.
- Look for any unusual processes taking up massive amounts of
memory or using unfamiliar names. - If you spot a suspicious process, right-click and open its file
location to delete it.
- Use an On-Demand Scanner:
- Once you have completed the built-in scan, download a reliable
on-demand tool like Malwarebytes. - Free Scan to catch anything the primary antivirus might have
missed.
