Computer Worms and How to Prevent Them

Almost all computer users have heard of 'worms' in a technological context before. These pieces of malicious software are hard to catch, but they can be dangerous to your system if left to spread undetected. They steal data, crash computer operating systems, and destroy entire computer networks. All computer users should be aware of these devious viruses and how to avoid them.

What is a computer worm?

Computer worms are a form of contagious malware. They replicate themselves independently across entire networks of computers. That allows them to take over entire computer networks. They exploit vulnerabilities in the network, specifically software vulnerabilities, in order to replicate and destroy.

The first worm was created by Robert Morris in 1988, and though he didn’t intend for it to be a malicious creation, the Morris worm infected its host machines many times over, resulting in computer shutdowns and nearly rendering the Internet unusable.

Since then, there have been several other notorious large-scale worm infections—such as the ILOVEYOU worm at the turn of the century in 2000 and the more recent 2017 WannaCry worm—but worm infections on smaller scales happen across the Internet all the time.

Computer worms are unfortunately difficult to catch and eliminate, since they aren’t dependent on software or a specific program to spread. Some worms are specifically used to evade a computer’s security system, while others are meant to perform explicitly malicious tasks: deleting files, stealing personal data, or acting as ransomware.

What is the difference between a virus and a worm?

The difference is that worms don’t require a host file, which sets them apart from computer viruses. The primary goal of a worm is to replicate itself as much as possible, ultimately overwhelming the network and slowing down the infected computers on it. Viruses cannot self-replicate and require host action: someone has to send it to another computer or network, download the infected file, or perform an action in some respect. Worms, however, need no user action to cause serious harm.

Types of computer worms

Internet worms

Internet worms attack popular visits with weak security. The worm replicates onto any device that visits the website. From there, the Internet worms distribute themselves to other computers connected via that Internet and local area network connections.

Email worms

Similar to phishing emails with compromised links, email worms distribution occurs via compromised email attachments or links. The attachments appear as media files. However, they are actually malicious programs that infect the victim’s contact list as soon as they click on the attachment. The emails can also just take the victim to an infected website, which will also start downloading malicious software onto the user’s laptop or computer.

Instant messaging worms

These worms, also known as social media worms, disguise themselves as links or attachments accompanied by a short message. Users often receive them from messaging apps such as Messenger or WhatsApp. They are also commonly send through direct messages on social media sites like Instagram or Twitter.

The messages appears to be from a friend. Furthermore, the message is typically rather friendly and inviting, like “Check out this picture of you!” or “This is hilarious!” Once the message is opened, the message gets replicated. It is sent out to their contacts, continuing the cycle and spreading the virus.

How to tell if you have a computer worm

Worms are difficult to detect on a computer. However, locating them and eliminating them is not impossible. If you’re dealing with computer worms, there will likely be telltale signs—though subtle—that indicate you have a problem.

Your computer starts to slow down abnormally. Some worms take up all of a computer’s resources by design. This decreases the device’s speed and performance because there isn’t enough processing power to properly run normal functions. If you notice that your computer isn’t moving as quickly or your programs are frequently crashing, it could indicate that you have a worm.

You notice files are missing from your desktop or folders. As mentioned above, worms have the ability to delete files off of your device. If you realize that you’re missing files off of your computer that you didn’t delete yourself—or you see them replaced with strange new files—it could indicate that a worm is at work.

Your computer runs out of storage faster than expected. Worms repeatedly replicate themselves. That means that the copies they make need to be stored on your device. This eats up your hard drive space, so if it seems that your storage is lower than it should be, look into it.

You discover messages sent to your contacts that you didn’t send yourself. Instant messaging or social media worms will send out strange messages to people you know without your awareness or permission. If you discover these messages in your ‘Sent’ folder, or if a friend reaches out to ask you about the weird message they got from you, it’s likely a computer worm causing the problem.

If your device is experiencing these problems and you think you may have a computer worm, run a virus scan as soon as possible to check for sure.

How to prevent computer worms

Though computer worms aren’t the same as computer viruses, a strong antivirus and anti-phishing security software program can still help prevent threats. Check to ensure that your program provides protection against viruses, ransomware, and spyware.

Invest in antivirus software early. That way, you can run a scan if you think you’ve been infected and remove the infected files. It’s also a good practice to encrypt files to make it harder for worms to attack.

Keep your system up-to-date to avoid all forms of malware, including worm infections, Trojan horses, keyloggers, and viruses. Install updates immediately, as soon as your provider makes them available. You can also use automatic updates to avoid performing manual updates on your own.

Do not open any suspicious emails or messages. Furthermore, avoid opening messages sent from someone you don’t know. These messages can be worms, and deleting them rather than clicking the links they contain help limit computer worm spread.

How to get rid of computer worms

If you’ve found that your computer is already infected with a worm, your best course of action is to use an antivirus program or scanner to clear your device. Microsoft provides a guide for dealing with all types of malware on infected systems, including worms, Trojan horses, and spyware. But, as always, the best defense is good offense; keep your computer software up-to-date to protect against malware and always practice good Internet safety.