Worms are malicious computer programs that are engineered to replicate themselves and spread to other computers over a network.

Computer worms can create copies of themselves on the local drive of a computer, removable media like flash drives, on the internet like attachments.

The primary objective of a worm is to spread itself to as many computers as possible using all the available resources it can use.

Over a network a worm is able to send copies of itself to other computers without any user involvement or being detected.

There are two major categories of computers worms. Some computer worms are only designed to spread themselves to other computers without changing the files on that computer or causing any significant damage to data stored on that computer.

Worms like this cause no damage to the computers or nodes but they do consume network bandwidth and may be even used for denial of service attacks or in the least harmful way they may make a network slow by consuming the bandwidth.

The second category of computer worms is more sophisticated and dangerous. Worms of this category can have payloads. In the payload section a worm may contain a virus or even may contain a code that would manipulate the files on a computer.

Worm like this can corrupt files, delete files, modify registry entries and replicate itself very quickly causing a major break down of network or crashing of computer systems attached to that network.

Worms may also be used to turn the computer into ‘zombie’ computers or bots that are then used for sophisticated and high tech attacks on targeted websites and servers. Worms are also used to gain backdoor access to a computer and then use it as a proxy to conceal identity while doing harmful or illegal operations on the Internet.

In its design and functionality it may resemble a computer virus. But worms are different from computer viruses, because viruses need a medium or source file to replicate and spread themselves. Viruses must be embedded in apparently useful programs or hidden inside other files, but worms can spread and replicate on their own without any user involvement or need of a media such as files or programs.

Worms spread like an uncontrolled nuclear chain reaction and within a very short period of time can infect computers globally. One example of such a worm is the email worm. To protect our computers against worms we must use standard and updated antivirus software and must not download or open email attachments from unknown senders or attachments that look suspicious.

You must used updated version of operating system, Internet browser and anti spyware program to maximize your security against computer worms. Computer worms are also called malware. Here it is ironic to know that the first computer worm was created accidentally.