What is a Computer Worm? Definition of Computer Worm?
Worms is a type of virus and malicious piece of code that replicates itself and it needs no hosted file or program to spread or work and mostly it spreads via the network.
What are types of Computer Worm? Different Types of Computer Worms?
Types of Computer worms
Email Worms: This type of worm spreads via email. This worm embedded itself in an email as an attachment to an email message or in a file as a link on a network resource such as a URL in an infected file or a website.
This activate when the recipient opened the email attachment or anyone opens the link inside the infected file. In both cases after opening the code is activated. When worms installed it will searched the email addresses inside the host computer. Then it starts the process and sending the worms without the intervention or input of the user. Famous examples are ILOVEU, Morris Worm.
Instant Messaging worms: It is a malicious code that replicates itself and spread via an instant message in a network after detecting the vulnerabilities (loopholes) in a network. After infecting the computer, it searches the contact list of the user and sends itself to all the contacts of the list. Famous Examples are Choke (first attaches to MSN messenger), CoolNow, and NewPic.
Internet Worms: It is a type of malicious program, code or script that replicates itself and spread using the internet without the intervention or knowledge of the user.
IRC (Internet Relay Chat) Worms: It is a program that spread through chat room and forums. There are two ways of its spreading via IRC Channels. First is sending the URL of the worm which contains the copy of the worm and second is infected file that
File sharing network worms: Most user, companies share the files and folders. This type of worm copies itself in the sharing folder or file with a harmless name. When file is shared the worm also spread via the shared folder or file and infected the receiver computer via file sharing.
How computer worms spread? How does Worm infect the computer?
Worm spreads and infects the system resources in following steps
1: Worms mostly spread via software or system vulnerabilities, in first stage the worm is a malicious code that detects the vulnerability (weakness) inside the system for exploit the system resources. It acts as penetration tool; once it detects the weakness it transfers the malicious code to your system or PC.
2: After infected the PC the worm discover other computer using network and detect vulnerabilities (weakness) of other computers to get access inside the system. This behavior of worm to spread of itself to other computer is known as payload.
3: In addition to damage the other file it replicates itself, so it occupies the memory space and use system resources like hard disk, memory and slow down the system performance. It can steal data or install a backdoor to give access to hacker to control a computer and its system settings.
When Computer Worms Started? History of Computer Worms?
The first computer worm program was not a harmful code instead it was designed to facilitate better usage of the computer network.
In 1971 the first worm program was written by Bob Thomas is called “creeper”. It was an experimental program written to prove the “Theory of self-reproducing automata” of John von Neumann’s. Creeper got access through ARPANET and infected DEC PDP-10 computers running the TENEX operating system and displayed the message “I’m the creeper, catch me if you can!”.
John Shock and Jon Hepps of Xerox’s Palo Alto Research Center, in the early 1980’s, designed the 5 worms to perform helpful task in a network.
In 1984 the first self replicating program code is written by Ken Thompson.
The first virus that spread through internet is Morris worm that is designed by the Robert Tappan Morris in 2nd November 1988. It worked by exploiting the vulnerabilities of UNIX send mail, finger and weak password features. It was not destructive worm, it just slow down the computer due to unnecessary processing.
Why computer worms are used? Disadvantages of computer worms?
- Worms is a malicious program that mainly designs to replicate itself and infects the computer on the network.
- It can breakdown the security of the network and steal the confidential data and password.
- Worms slow down the system performance because during replicating it uses the system resources and halt or crash the system unexpectedly.
- Unexpected termination of programs, unusual sounds, images can appear suddenly.
- Warning messages from antivirus program appears and the email sends to contact list without the knowledge of the user.
- Operating system malfunction and system error messages appear.
- Firewall warning display.
- Web browser performance slows down.
- Programs open and run automatically.
- Files missing or deleted, unknown files and icon appear on desktop.