What are Computer Worms? And What to Do When You’re Infected?


Computerworm Spam Mail LaptopA computer worm, or simply worm, is a type of malware that can infect computers and spread automatically. The difference with regular computer viruses is that worms don’t have to be installed by the owner. The worm uses vulnerabilities in networks and operating systems to spread. Worms often have harmful software attached to them. Below you can read what type of worms there are and how you can protect yourself against them. Moreover, you can find out what to look for to see if your device has been infected with a worm.

How do you get Infected with a Computer Worm?

A computer worm doesn’t need to be installed by the owner of the device. Back in the day, computers were infected by floppy discs with worms attached. Of course, this doesn’t happen anymore, but sometimes they will use a USB stick for the first infection. However, nowadays worms mostly enter your computer through harmful emails or links.

When a computer or network is infected with a worm, the worm will automatically look for other devices to infect. This means that, when you connect your infected laptop to your home network the worm will try to infect the network. Next the worm will try to find other devices through the network such as laptops, smartphones, and tablets. This means you can get infected just by connecting to an infected network. Below you can see how this works.

Computerworm Infection Netwerk

Different Types of Computer Worms

There are worms for every operating system. So, whether you have Windows, Linux, iOS, or Android device, you can always get infected. However, some worms are made specifically for one type of operating system. This means it will only be able to infect, for instance, Windows devices. Moreover, you can distinguish between some different types of worms. Below you can read about these different worms.

Payload Worms

The most common worm is the one that infects your device with harmful software. That type of worm is a hybrid that both actively tries to find new devices and install malware at the same time. Hackers can use this type of hybrid worm to read or delete files. The adware, spyware, ransomware, or other types of malware that are attached to the worm are called the “Payload”. In a way they just use the worm as a way into devices to spread harmful software.

Bot Worms

Besides the type of hybrid worms there are also bot worms. Bot worms turn the infected device into a “zombie” or “bot”. These infected devices form a network which we call a botnet. A hacker or “botmaster” controls this network and with it, all the infected computers. The devices can carry out any command the botmaster gives them. This way the botmaster can use the botnet to visit a website with a large number of devices at the same time, causing the servers to give in. This type of attack is a so-called DDoS attack.

Email Worms

Email worms are becoming quite common. These worms spread by automatically sending an email to all the addresses in your contact list, once your computer is infected.. This used to happen mostly through emails but nowadays social media are ideal for these worms. Maybe you’ve had strange messages from a Facebook contact you hadn’t spoken to in years. This probably was a worm trying to get access to your device.

Ethical Worms

Finally, there is also a type of worm we call “ethical” worms. These worms don’t have harmful software attached to them but updates or patches for known security leaks. They infect older systems that show security leaks to try and patch these. This sounds like a good way to solve these problems, but in reality, hardly anybody uses this type of worm anymore. Some people object to the use of ethical worms because they still invade their system without permission.

What can you do to Prevent Infection?

The most important thing you can do to prevent infection is to always update your operating system, software, and virusscanner. Worms use security breaches in these systems to gain access to your device. Older systems that haven’t been updated recently often have many weak spots because the manufacturer has stopped updating it. New systems are constantly improved and updated accordingly. For this reason, new systems have less chance of being infected.

Secondly, you always have to be watchful of strange emails, files attached to emails, and messages on social media. Sometimes you will find links in there that contain worms. You can do the following things to prevent infection:

  • Never open emails you do not trust.
  • Don’t download files attached to strange emails
  • Never click on links you don’t trust (in emails, on websites, or on social media).

Finally, it is important to have a good virusscanner. A good virus scanner is ideal if you want to spot worms and place them in quarantine. A virusscanner will let you know when it has discovered a worm and take the appropriate actions to delete it.

How do you Know if you are Infected with a Computer Worm?

It can be quite difficult to find out if your device has been infected with a worm or not. Some symptoms of a computer worm can also apply to other types of malware, or they might even mean that your computer is simply getting old. However, if your computer shows more than one of these symptoms there is a good chance it is infected:

  • Worms magnifying glassYour computer freezes or crashes
  • Your computer is making strange noises or shows strange messages or pictures
  • You get a message from your Firewall
  • Files have been altered, but not by you
  • You get an error message from your operating system
  • You are missing important files
  • Strange files or shortcuts appear on your desktop
  • Your computer is slow
  • Your browser is slow or doesn’t work
  • Messages are sent to people from your contact list without you knowing, through email or social media

How can I get rid of a Computer Worm?

If a worm infects your device it can be very difficult to get rid of it. The best thing you can do in such a situation is check online how you can best get rid of this specific type of worm. As you have been able to read, there are many different types of worms, which means there’re also different methods for getting rid of them. One step that is always important is to take your device off the local network immediately. This way you can prevent the worm from spreading to other devices in your network. Also check all external storage devices, such as USB sticks, separately for worms.

Final Thoughts

Computer worms are harmful types of malware that can bring a lot of trouble with them. These worms can automatically find their way around a network to spread malware over all the connected devices. There are many types of worms so if you do get infected you need to find out how to deal with your specific worm accordingly. You can protect yourself against worms by keeping your operating system and software up-to-date and by keeping an eye out for strange messages or links.

Tech journalist
Tove has been working for VPNoverview since 2017 as a journalist covering cybersecurity and privacy developments. She has broad experience developing rigorous VPN testing procedures and protocols for our VPN review section and has tested dozens of VPNs over the years.