Page 141 - DCAP516_COMPUTER_SECURITY

Unit 11: Threats in Network

Host computer worms are entirely contained in the user’s computer and use network Notes
connections only to copy themselves to other computers. Network worms consist of
multiple parts or segments, each running on different machines, uses the network for
several communication purposes. Spreading a part from one machine to another is only
one of those purposes.

Did u know? Surprisingly, the first worm in history was actually designed to do good
rather than to harm networks. The first ever worm was developed for the assistance of air
traffic controllers by Bob Thomas in 1971. This worm program notified air traffic controllers
when the controls of a plane moved from one computer to another. This worm was named
as ‘creeper.’ The major difference from most worms was that this creeper did not reproduce
itself.
10. Blended Threats: Current computer threats are capable of significant damage to systems
and data, but are difficult to classify under a single category, such as a “virus,”\”Trojan” or
even “hacker exploit.” Thus, these threats are combining to create a new type of computer
security concern experts are calling “blended threats.” Hackers, those trying to gain
unauthorized access to computers and computer networks, and malicious mobile code,
computer viruses and worms, are increasingly working in tandem. Because of these new
blended threats, computer professionals and IT administrators must learn about the types
of threats that exist to evaluate their current security strategies and develop comprehensive,
adaptable protection.

11. E-mail Related Threats: E-mail has become one of the world’s most preferred forms of
communication. Billions of e-mail messages navigate the globe daily. Like any other
form of communication, e-mail can also be misused. The ease, speed and relative anonymity
of e-mail has made it a powerful tool for criminals. Some of the major e-mail related
threats are discussed as below.
E-mail spoofing is an effective medium to mislead people. A spoofed e-mail is an e-mail
that appears to originate from one source but has actually emerged from another source.
E-mail spoofing is usually done by falsifying the name and/or e-mail address of the
originator of the e-mail. E-mail spoofing is very often used to commit financial crimes. It
becomes a simple thing not just to assume someone else’s identity but also to hide one’s
own. The person committing the crime understands that there is very little chance of his
actually being identified. E-mail spoofing can also be used to spread misinformation, and
even to secure unauthorised access to computers.

E-mails are the fastest and easiest ways to circulate Trojans, viruses, worms and other
malicious code over the Internet. Hackers often bind Trojans, viruses, worms and other
computer contaminants with e-greeting cards and then e-mail them to unsuspecting persons.
Such mails can also be bound with software that appears to be an anti-virus patch. For
example, a person receives e-mail from a fake address like information@mcaffee.com.
Now, this is a spoofed e-mail but the receiver does not know this. The e-mail simply
seems to be an attachment of a security patch that can be downloaded to detect a certain
new virus. Most of the users would download such an e-mail (if they know that McAffee
is a popular anti-virus software), which may be a Trojan or a virus itself.
Another e-mail related potential threat is E-mail bombing. E-mail bombing refers to
sending a large amount of e-mails to the victim resulting in the victim’s e-mail account (in
case of an individual) or servers (in case of a company) crashing. There are several hacking
tools available to automate the process of e-mail bombing. These tools send multiple
e-mail from many different e-mail servers, which makes it very difficult for the victim to
protect himself.

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