This document defines and describes computer worms. It notes that worms are a type of malicious software that spreads to infect other computers without user interaction by exploiting vulnerabilities. It provides examples of different types of worms like email worms and bot worms. The document explains how worms spread and differ from viruses, noting worms can replicate independently while viruses typically require human interaction. It concludes by recommending measures to prevent worm infections like keeping software updated, using firewalls and antivirus, and being cautious of email attachments.
2. What is Worm?
• A computer worm is a type of malicious software program whose primary function is to infect other computers
while remaining active on infected systems. A computer worm is self-replicating malware that duplicates itself to
spread to uninfected computers. Worms often use parts of an operating system that are automatic and invisible to
the user. It is common for worms to be noticed only when their uncontrolled replication consumes system
resources, slowing or halting other tasks.
3. How computer worms spread?
• A computer worm infection spreads without user interaction. All that is necessary is for the computer worm to
become active on an infected system. Before widespread use of networks, computer worms were spread through
infected storage media, such as floppy diskettes, which, when mounted on a system, would infect other storage
devices connected to the victim system. USB drives are still a common vector for computer worms.
4. Types of computer worms
• There are several types of malicious computer worms:
A computer virus or worm hybrid is a piece of malware that spreads like a worm,
but that also modifies program code like a virus -- or else carries some sort of
malicious payload, such as a virus, ransomware or some other type of malware.
A bot worm may be used to infect computers and turn them into zombies or bots,
with the intent of using them in coordinated attacks through botnets.
Instant messaging, or IM worms propagate through instant messaging services and
exploit access to contact lists on victim computers.
Email worms are usually spread as malicious executable files attached to what appear
to be ordinary email messages.
5. Differences between worms and viruses
Worms Virus
Spreads independently Requires a host
Doesn’t require human interaction Triggered by human interaction
Often arrives through a software vulnerability Often arrives through an infected file or program
(file-infector)
6. How to prevent a computer worm
• Measures that will help prevent the threat of computer worm infections include:
Keeping up to date with operating systems and all other software patches and updates
will help reduce the risk due to newly discovered vulnerabilities.
Using firewalls will help reduce access to systems by malicious software.
Using antivirus software will help prevent malicious software from running.
Being careful not to click on attachments or links in email or other messaging
applications that may expose systems to malicious software.
Encrypt files to protect sensitive data stored on computers, servers and mobile devices
7. Conclusion
• In conclusion, Computer worms are among the most common types of malware. They spread over computer
networks by exploiting operating system vulnerabilities. Worms typically cause harm to their host networks by
consuming bandwidth and overloading web servers. Computer worms can also contain “payloads” that damage host
computers. Payloads are pieces of code written to perform actions on affected computers beyond simply spreading
the worm. Payloads are commonly designed to steal data or delete files. Some payloads even create backdoors in
host computers that allow them to be controlled by other computers. Malicious parties can use networks of these
infected computers (“botnets”) to spread spam and perform denial-of-service attacks. So we should be aware of it.