What is a Computer Worm Virus?
A computer Worm is a standalone program that spreads itself autonomously across a network. To spread, worms typically exploit a vulnerability on a computer's operating system or computer software. Unlike viruses, which are dependent on host programs to operate, worms are capable of self-replication without human input.
A computer worm virus will cause a plethora of problems once it has gained access to a system. This includes the consumption of memory and bandwidth, which inevitably leads to overloads and malfunctions. Computer worms are also capable of stealing sensitive data, installing backdoors for unauthorized access and corrupting files. This poses a significant threat to not only the individual system in question, but also the network infrastructure.
Computer worms display opportunistic behavior, much like their biological counterparts. They rely on deception to infect hosts and display ruthless destructiveness when doing so. They have a tendency to rapidly infect inadequately protected systems.
Classification of worms: What are the different types of worm viruses and how do they spread?
Worm viruses are classified into different types based on how they propagate and transmit. Here are a few examples of the most common types of computer worm virus classifications:
- Email Worms: Email worms spread via files attached to email messages. Once the infected attachment is opened, the worm replicates itself and sends copies to every contact in the user's contact list, thus propagating further.
- IM Worms: IM (Instant Messenger) worms spread through IM networks by sending copies of themselves to all contacts within the user's address brook. IM worms tend to exploit the trust associated with IM platforms in order to deceive users into opening malicious links and files which further enable their spread.
- IRC Worms: IRC (Internet Relay Chat) Worms utilize IRC networks to transmit themselves to other host machines. The most common way in which IRC worms transmit is by dropping a script into the IRC client directory of the infected machine, which allows them to spread to other users that are connected to the same network.
- Net Worms: Net worms locate new hosts by exploiting shared files that exist across a network, including servers and hard drives which accessible by multiple machines via a local-area network (LAN). Exploiting vulnerabilities within network protocols allows net worms to spread incredibly quickly to interconnected devices.
- P2P Worms: P2P (peer-to-peer) worms spread through peer-to-peer networks, taking advantage of the decentralized nature of P2P connections. This allows them to distribute copies of themselves to users sharing files. They typically disguise themselves as legitimate files in order to evade detection and continue wreaking havoc.
Real world example of computer worms
Computer worm viruses have caused widespread havoc and damage across a multitude of sectors and industries in recent history. Here are just a few notable examples that made the headlines:
- Morris Worm: Released in 1988, the Morris Worm is understood to be the first ever computer worm to spread across the early internet. This was created by Robert Tappan Morris Jr. and targeted vulnerabilities in Unix programs. Ultimately, the Morris Worm infected approximately 10% of the systems connected to the ARPANET (The Advanced Research Projects Agency Network – the forerunner of the internet), which led to significant disruptions.
- ILOVEYOU: Launched in 2000, the ILOVEYOU worm virus spread via email attachments that were disguised as text files and instant messaging scripts. Due to its ability to spread rapidly through Microsoft Outlook contacts, it infected millions of users worldwide, causing billions of dollars' worth of damages while disrupting enterprise email services across the globe.
- Bagle Worm: The Bagle worm quickly accrued notoriety in early 2004 for its mass-mailing capabilities and subsequent rapid spread. Having disguised itself in a variety of file types, Bagle worm spread via email attachments. The initial strain, known as Bagle.A, infected numerous systems before dying out by the end of January 2004. This was then replaced by its more dangerous variant Bagle.B, which ran for a similar timescale before eventually halting propagation on February 25, 2004.
- Stuxnet: Initially identified in 2010, Stuxnet was a complex worm specifically designed to interfere with the production of nuclear weaponry in Iran. This was one of the first viruses of its kind to reach the public domain. After spreading through various vile-sharing services, it exploited Windows operating system flaws to disrupt Iran's nuclear centrifuges.
- WannaCry: WannaCry ransomware is not a worm per se, but it did use a worm to infect Windows computers and encrypt files, demanding ransom payments for the relevant decryption keys. It caused substantial financial and operational havoc in large corporations and critical infrastructure worldwide.
The examples above illustrate the diverse capability and potential havoc that worm viruses can wreak if they are allowed to propagate and transmit.
How do I know if I have a computer worm virus?
The symptoms of a computer worm are very similar to that of a virus. Infected computers will typically display a few tell-tale signs, such as:
- Slow computer speed and performance
- Unexpected crashing of programs
- Missing files
- Files replaced with an alternative
- Free hard drive space getting eaten up
- Alerts from your firewall
- Programs and websites opening automatically
- Irregular browser performance
- Emails sent to your contacts without knowledge
- Unusual sounds
- Unusual warning messages
How to avoid infection by a worm virus
Make sure you have an update anti-virus or anti-spyware application installed with real-time protection enabled to block worms from entering your system or at least scan and remove the worm if you are infected by one.
Remember to keep your Windows operating system current using a supported version of Windows and having the latest updates installed.
Do not open emails and attachments from unknown senders; you are better safe than sorry!
If you can, disable JavaScript within your web browser. This will ensure rogue scripts on websites pose no threat to you, but will stop some legitimate sites from working properly.
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FAQs
Q: What is a worm virus? [+]
A: A worm virus refers to a type of malicious software that replicates without human input, autonomously spreading across various networks and systems.
Q: How do computer worms spread? [+]
A: Computer worms typically exploit vulnerabilities in software to spread. They can transmit through email attachments, instant messages, spam emails and local area networks, to name just a few examples. Once the infected file or link is opened, the worm is able to automatically download on to the device without being detected.
Q: How do computer worms harm your device? [+]
A: There are a number of ways in which computer worms may harm your device. This includes the consumption of memory and bandwidth, the theft of sensitive information, the installation of unauthorized backdoors and the creation of corrupt files. Due to their autonomous nature, the speed with which they can impact entire networks and cause major disruption is alarming.
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