365 Computer Security Training

A computer worm should not be confused with a computer virus. Like viruses, worms are self-replicating programs that use the network to send copies of themselves to other nodes. But unlike viruses, worms do not need to attach themselves to existing programs. They can self-replicate, completely without user intervention. Worms cause damage in the form of consuming network bandwidth while viruses corrupt and damage existing files on a targeted machine.

The very first computer worm was unleashed accidentally in 1988 by Robert Tappan Morris. Another well-known computer worms was the SQL Slammer Worm of 2003, which owing to vulnerability in the Microsoft SQL, spread itself across the Internet.

The Blaster Worm used the Microsoft DCOM RPC, which is a technology for communication among software components across networked computers, in order to spread itself.

Some worms like the 1999 Melissa Worm, the 2003 Sobig Worms and the 2004 Mydoom worms used email to spread. These worms had some qualities of Trojans whereby they attached themselves to an email attachment and prompted the end user to open the attachment thereby causing infection to the computer.

To prevent computer worms infection and spreading:
• Keep the operated system, hardware, and software patched and up to date.
• Never open unsolicited email attachments because there could be a Trojan-like worm inside. The worms in attachments are not just limited to .exe files but can also be contained in Word and Excel sheets.

Worms can also spread through Instant Messaging services. There also may be links, which lead to malicious sites. Once clicked, the worm may be transferred through the network to your computer.

However worms are not always malicious. There have been ‘good’ worms as well! For example, the Nachi family of worms had been created to perform useful functions like download and install patches from Microsoft’s website to fix vulnerabilities in the host system.

However, the most important protection against this especially dangerous type of malware is caution and good antivirus software.