Worms are malicious computer programs 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, and 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 can send copies of itself to other computers without any user involvement or being detected.
There are two significant categories of computer 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 consume network bandwidth and may even be 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 include 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 significant network breakdown or crashing of computer systems attached to that network.
Worms may also turn the computer into ‘zombie’ computers or bots 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. Viruses must be embedded in apparently useful programs or hidden inside other files. Still, worms can spread and reproduce independently without user involvement or the need for media such as files or programs.
Worms spread like an uncontrolled nuclear chain reaction and can infect computers globally within a brief period. 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 use an updated version of the operating system, Internet browser, and anti-spyware program to maximize your security against computer worms. Computer worms are also called malware.