A worm is a type of malware that replicates without any intervention. It jumps from one digital device to another by leaving a copy of itself on anything that connects to the infected system. 

For instance, it can stay on your computer seemingly harmless until you plug a USB stick. That thumb drive will carry a copy of the worm to other computers it gets plugged in to. Worms can also end up in a computer through a malware-carrying email attachment or when users access a contaminated website.

Digital worms behave very much like the parasitic worms after which they were named. They live within the bodies of animals. Some of them may transfer into other animals that come in contact with their host. So digital worms spread across computers and devices the same way parasitic worms spread throughout the population.

Other interesting terms…

Read More about “Computer Worm”

Computer worms often use areas of an operating system (OS)—the program that lets your system run—where they can remain invisible to the users. Usually, their presence only gets noticed when their continuous replication consumes too many resources, causing a computer to slow down or “hang.”

How does a Computer Worm Work?

Computer worms can get into systems that have software vulnerabilities. At times, they are spread as attachments to emails and sent as seemingly harmless files in instant messages. When opened, they instantly infect devices and start spreading.

Some computer worms can change and delete files. Others can cause the download of even more malware onto devices. The additional malware can do anything from exhausting system resources to stealing data and letting a hacker take total control over affected computers.

Types of Computer Worms

There are various types of computer worms, including:

1. Virus-worm hybrids

These spread like normal computer worms but also alter programs like viruses. They are typically used to distribute other viruses or malware.

2. Bot worms

These convert infected computers and any devices connected to them into zombies or bots. They allow hackers to use the botnet—a group of bots—to spread spam or conduct more destructive distributed denial-of-service (DDoS) attacks (when multiple compromised devices or systems attack a single system)

3. IM worms

These spread through different instant messaging (IM) apps and services. They can access contact lists and spread to your contacts’ devices.

4. Email worms

These spread through emails as attachments or downloads from embedded links.

5. Ethical worms

Not all computer worms are harmful, though. These, for instance, were explicitly designed to spread through networks to deliver patches to address security weaknesses.

How to Protect Against Computer Worms

Computer worm infections can be challenging to remedy. But, the best antimalware solutions can detect and remove them. So if you believe your computer is infected, run a scan, and remove any compromised files. Then, prevent them from ever getting into your computer again by setting up a firewall rule that locks them out. Make sure you avoid downloading suspicious files and clicking suspicious links, too, especially if you don’t personally know who sent them.

Interesting Facts

Did you know that the Conficker/Downad worm, first seen in 2008, is still active to this day? In its heyday, it successfully infected more than 15 million devices, earning it the reputation of being “one of the most dangerous and sophisticated threats” ever seen. We still see warnings about it from the biggest cybersecurity companies to date.