Computer worm

Source: Wikipedia, the free encyclopedia.
This article is about coding of a worm. For the data storage device, see write once read many. For other uses, see Worm (disambiguation).
Not to be confused with Computer virus.
CEO Bill Gates
by the worm's creator
Conficker worm

A computer worm is a standalone malware computer program that replicates itself in order to spread to other computers.[1] It often uses a computer network to spread itself, relying on security failures on the target computer to access it. It will use this machine as a host to scan and infect other computers. When these new worm-invaded computers are controlled, the worm will continue to scan and infect other computers using these computers as hosts, and this behaviour will continue.[2] Computer worms use recursive methods to copy themselves without host programs and distribute themselves based on exploiting the advantages of exponential growth, thus controlling and infecting more and more computers in a short time.[3] Worms almost always cause at least some harm to the network, even if only by consuming bandwidth, whereas viruses almost always corrupt or modify files on a targeted computer.

Many worms are designed only to spread, and do not attempt to change the systems they pass through. However, as the Morris worm and Mydoom showed, even these "payload-free" worms can cause major disruption by increasing network traffic and other unintended effects.

History

Morris worm source code floppy diskette at the Computer History Museum

The term "worm" was first used in

John Brunner's 1975 novel, The Shockwave Rider. In the novel, Nichlas Haflinger designs and sets off a data-gathering worm in an act of revenge against the powerful men who run a national electronic information web that induces mass conformity. "You have the biggest-ever worm loose in the net, and it automatically sabotages any attempt to monitor it. There's never been a worm with that tough a head or that long a tail!"[4] "Then the answer dawned on him, and he almost laughed. Fluckner had resorted to one of the oldest tricks in the store and turned loose in the continental net a self-perpetuating tapeworm, probably headed by a denunciation group "borrowed" from a major corporation, which would shunt itself from one nexus to another every time his credit-code was punched into a keyboard. It could take days to kill a worm like that, and sometimes weeks."[4]

The second ever computer worm was devised to be an anti-virus software. Named

Creeper
program (the first computer worm, 1971).

On November 2, 1988, Robert Tappan Morris, a Cornell University computer science graduate student, unleashed what became known as the Morris worm, disrupting many computers then on the Internet, guessed at the time to be one tenth of all those connected.[5] During the Morris appeal process, the U.S. Court of Appeals estimated the cost of removing the worm from each installation at between $200 and $53,000; this work prompted the formation of the CERT Coordination Center[6] and Phage mailing list.[7] Morris himself became the first person tried and convicted under the 1986 Computer Fraud and Abuse Act.[8]

Conficker, a computer worm discovered in 2008 that primarily targeted Microsoft Windows operating systems, is a worm that employs 3 different spreading strategies: local probing, neighborhood probing, and global probing.[9] This worm was considered a hybrid epidemic and affected millions of computers. The term "hybrid epidemic" is used because of the three separate methods it employed to spread, which was discovered through code analysis.[10]

Features

Independence

Computer viruses generally require a host program.[11] The virus writes its own code into the host program. When the program runs, the written virus program is executed first, causing infection and damage. A worm does not need a host program, as it is an independent program or code chunk. Therefore, it is not restricted by the host program, but can run independently and actively carry out attacks.[12][13]

Exploit attacks

Because a worm is not limited by the host program, worms can take advantage of various operating system vulnerabilities to carry out active attacks. For example, the "Nimda" virus exploits vulnerabilities to attack.

Complexity

Some worms are combined with web page scripts, and are hidden in HTML pages using VBScript, ActiveX and other technologies. When a user accesses a webpage containing a virus, the virus automatically resides in memory and waits to be triggered. There are also some worms that are combined with backdoor programs or Trojan horses, such as "Code Red".[14]

Contagiousness

Worms are more infectious than traditional viruses. They not only infect local computers, but also all servers and clients on the network based on the local computer. Worms can easily spread through

shared folders, e-mails,[15] malicious web pages, and servers with a large number of vulnerabilities in the network.[16]

Harm

Any code designed to do more than spread the worm is typically referred to as the "

payload". Typical malicious payloads might delete files on a host system (e.g., the ExploreZip worm), encrypt files in a ransomware attack, or exfiltrate data such as confidential documents or passwords.[citation needed
]

Some worms may install a

spam or performing DoS attacks.[17][18][19]

Some special worms attack industrial systems in a targeted manner.

SIMATICWinCC systems to attack the embedded programmable logic controllers of industrial machines. Although these systems operate independently from the network, if the operator inserts a virus-infected drive into the system's USB interface, the virus will be able to gain control of the system without any other operational requirements or prompts.[20][21][22]

Countermeasures

Worms spread by exploiting vulnerabilities in operating systems. Vendors with security problems supply regular security updates

zero-day attack
is possible.

Users need to be wary of opening unexpected email,[24][25] and should not run attached files or programs, or visit web sites that are linked to such emails. However, as with the ILOVEYOU worm, and with the increased growth and efficiency of phishing attacks, it remains possible to trick the end-user into running malicious code.

anti-spyware software are helpful, but must be kept up-to-date with new pattern files at least every few days. The use of a firewall
is also recommended.

Users can minimize the threat posed by worms by keeping their computers' operating system and other software up to date, avoiding opening unrecognized or unexpected emails and running firewall and antivirus software.[26]

Mitigation techniques include:

Infections can sometimes be detected by their behavior - typically scanning the Internet randomly, looking for vulnerable hosts to infect.[27][28] In addition, machine learning techniques can be used to detect new worms, by analyzing the behavior of the suspected computer.[29]

Worms with good intent

A helpful worm or anti-worm is a worm designed to do something that its author feels is helpful, though not necessarily with the permission of the executing computer's owner. Beginning with the first research into worms at

Nachi family of worms tried to download and install patches from Microsoft's website to fix vulnerabilities in the host system by exploiting those same vulnerabilities.[31] In practice, although this may have made these systems more secure, it generated considerable network traffic, rebooted the machine in the course of patching it, and did its work without the consent of the computer's owner or user. Regardless of their payload or their writers' intentions, security experts regard all worms as malware. Another example of this approach is Roku OS patching a bug allowing for Roku OS to be rooted via an update to their screensaver channels, which the screensaver would attempt to connect to the telnet and patch the device.[32]

One study proposed the first computer worm that operates on the second layer of the OSI model (Data link Layer), utilizing topology information such as Content-addressable memory (CAM) tables and Spanning Tree information stored in switches to propagate and probe for vulnerable nodes until the enterprise network is covered.[33]

Anti-worms have been used to combat the effects of the

Blaster worm, Welchia infected computers and automatically began downloading Microsoft security updates for Windows without the users' consent. Welchia automatically reboots the computers it infects after installing the updates. One of these updates was the patch that fixed the exploit.[35]

Other examples of helpful worms are "Den_Zuko", "Cheeze", "CodeGreen", and "Millenium".[35]

Art worms support artists in the performance of massive scale ephemeral artworks. It turns the infected computers into nodes that contribute to the artwork.[36]

See also

References

  1. ^ Barwise, Mike. "What is an internet worm?". BBC. Archived from the original on 2015-03-24. Retrieved 9 September 2010.
  2. PMID 25978309
    .
  3. PMID 22711861
    .
  4. ^
    ISBN 978-0-06-010559-4
    .
  5. ^ "The Submarine". www.paulgraham.com.
  6. ^ "Security of the Internet". CERT/CC.
  7. ^ "Phage mailing list". securitydigest.org. Archived from the original on 2011-07-26. Retrieved 2014-09-17.
  8. ISBN 978-0-314-17719-3
    .
  9. PMID 25978309
    .
  10. PMID 25978309
    .
  11. ^ "Worm vs. Virus: What's the Difference and Does It Matter?". Worm vs. Virus: What's the Difference and Does It Matter?. Retrieved 2021-10-08.
  12. OCLC 897634290
    .
  13. S2CID 2242419
    .
  14. ISBN 978-3-319-56972-7
  15. S2CID 243976629
    .
  16. S2CID 15572850
    .
  17. ^ Ray, Tiernan (February 18, 2004). "Business & Technology: E-mail viruses blamed as spam rises sharply". The Seattle Times. Archived from the original on August 26, 2012. Retrieved May 18, 2007.
  18. ^ McWilliams, Brian (October 9, 2003). "Cloaking Device Made for Spammers". Wired.
  19. ^ "Hacker threats to bookies probed". BBC News. February 23, 2004.
  20. S2CID 154754335
    .
  21. S2CID 154019562
    .
  22. ISBN 978-94-6252-012-7
    .
  23. ^ "USN list". Ubuntu. Retrieved 2012-06-10.
  24. ^ "Threat Description Email-Worm". Archived from the original on 2018-01-16. Retrieved 2018-12-25.
  25. ^ "Email-Worm:VBS/LoveLetter Description | F-Secure Labs". www.f-secure.com.
  26. ^ "Computer Worm Information and Removal Steps". Veracode. 2014-02-02. Retrieved 2015-04-04.
  27. doi:10.1109/tdsc.2007.70230
    .
  28. ^ "A New Way to Protect Computer Networks from Internet Worms". Newswise. Retrieved July 5, 2011.
  29. S2CID 1097834
    .
  30. S2CID 1639205
    .
  31. ^ "Virus alert about the Nachi worm". Microsoft.
  32. ^ "Root My Roku". GitHub.
  33. S2CID 3260588
    .
  34. ^ "vnunet.com 'Anti-worms' fight off Code Red threat". Sep 14, 2001. Archived from the original on 2001-09-14.
  35. ^ a b c The Welchia Worm. December 18, 2003. p. 1. Retrieved 9 June 2014.
  36. ^ Aycock, John (2022-09-15). "Painting the Internet". Leonardo. 42 (2): 112–113 – via MUSE.

External links


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