Almost all of us have heard the terms computer worm, virus, and trojan. What are worms, viruses, and trojans? How do they infect a system? And how can we prevent them? Let’s discuss that in this article.

What is malware?

Malware is an abbreviated form of Malicious Software. It indicates any software that is used for malicious purposes like stealing private data, corrupting files, crashing hard disks, extorting money, etc. They infect a computer stealthily without the user’s knowledge. And then they spread themselves. Worms, viruses, and trojans are types of malware.

Worm vs Virus vs Trojan – What is the difference between Worm, Virus, and Trojan?

How are worms, viruses, and trojans different from each other? Let’s try to understand that.

What is a computer worm?

A computer worm is malware that infects a computer without the user’s knowledge. And then it spreads through self-replication.

But unlike computer viruses, worms do not need to attach themselves to an existing program. They often use computer networks and spread themselves by taking advantage of security vulnerabilities present in existing software.

Worms almost always cause some harm to the network by taking lots of bandwidth. After infecting a computer, they can delete files, use the computer as a botnet (What is a botnet?), and use the infected computer’s computational resources for illegal activities, send spam, or even blackmail companies by threatening DoS or Denial of Service Attacks.

What is a computer virus?

Computer virus also infects a computer and then spreads itself to infect more computers. It normally attaches itself to another computer program so that when a user executes the program on his computer, the virus silently infects the computer. Just to give a common example, Microsoft Word Document supports macros, and it can execute macros while opening the document. A virus can attach itself to a Word Document as a macro so that whenever a user opens the document, the code of the virus is executed, and the computer is infected.

Computer viruses can attach themselves to data files also. For example, a virus can attach its code to a …