Malware isn’t limited to viruses. While viruses typically rank as the most common form of malware, there are other forms of malicious software that can affect your computer, such as worms. Worms share many of the same characteristics as viruses. They are both self-replicating, and they are both designed to cause harm. But worms have their own unique features that distinguish them from viruses and all other forms of malware. Here are five things you need to know about worms and how they work.

#1) Doesn’t Require a Host Program

Unlike viruses, worms don’t need a host program. Worms operate as independent programs or pieces of malicious code. This means worms can affect your computer without attaching themselves to legitimate programs.

#2) Spread Quickly

If your computer is infected with a worm, you should isolate it immediately to mitigate the damage. Worms can quickly spread when left unchecked. They have the ability to self-replicate, meaning they will copy their malicious code and write it to other connected drives or devices. By isolating your computer, you can prevent the worm from spreading. The sooner you isolate the infected computer, the easier it will be to recover from the worm infection.

#3) Leverage Network Connections

There are different types of worms, but most of them leverage network connections to spread. In other words, they spread over the internet or local area networks (LANs). A typical worm will exploit a weakness, such as unpatched software or a default username and password combination. After gaining access to the computer, it will begin to self-replicate while simultaneously carrying out its destructive activities.

#4) Come With a Payload

Worms come with a payload. What is a payload exactly? When used in the context of malware — worms, viruses, etc. — a payload is a destructive activity. All forms of malware are designed to cause harm. The mechanics by which they cause harm is determined by their payload. Some worms are designed to erase data, whereas others are designed to steal data, consume resources and more. The worm’s payload will determine its destructive activity or activities.

#5) Drive-By-Downloads

Some worms are designed to spread via drive-by-downloads. Drive-by-downloads involve a user clicking a malicious download link. The user may think he or she is downloading a legitimate program. If the download link is malicious, though, the user will end up downloading a piece of malware, such as a worm. Drive-by-downloads are commonly used by hackers to deploy malware like worms.