Transcript IT security

IT internet security
The Internet
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The Internet - a physical collection of
many networks worldwide which is referred
to in two ways:
The internet (lowercase i) is any collection
of separate physical networks,
interconnected by a common protocol to
form a single logical network
The Internet (uppercase I) is the
worldwide collection of interconnected
networks that uses Internet Protocol (IP)
to link the various physical networks into a
single logical network
The World Wide Web
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A network of information contained in web pages
which are found and viewed by using web browser
programs eg Internet Explorer or Netscape
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Technically, the World Wide Web is all the
resources and users on the Internet that are using
the Hypertext Transfer Protocol (HTTP)
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It links pages and sites together using hypertext
links
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The web is not the same as the Internet. It is just
part of it, and only one of several Internet
environments
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Others include email, Internet Relay Chat, FTP
(File transfer Protocol), and Usenet news groups
Browser
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A software application used to
navigate the www to locate and
display Web pages eg Explorer
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A World Wide Web access program
that requests documents or other files
from a web server, and displays them
on a user's display device
Intranet
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A private network of computers within
an organization used to share
information and computing resources
It sits behind a firewall and is only
accessible to people who are
members of the same organization,
using passwords and logins
Uses regular Internet protocols and
looks like a private version of the
Internet
Extranet
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It is an intranet that is partially
accessible to authorized outsiders
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You can only access an extranet if
you have a valid username and
password, and your identity
determines which parts of the
extranet you can access
Viruses
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Self-replicating programs that spread by inserting
copies of itself into executable code or documents
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Can only spread from one computer to another
when its host is taken to the uninfected computer,
eg sending it over a network or carrying it on a
removable disk
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May cause a simple prank that pops up a message
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May destroy programs and data right away or on
a certain date
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Can lie dormant and do its damage once a year.
eg the Michaelangelo virus contaminates the
machine on Michaelangelo's birthday
Worms
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A computer worm is a self-replicating
computer program, similar to a computer
virus
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It is self-contained and does not need to be
part of another program or attach itself to
other files or programs to spread itself
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It may be designed to do any number of
things, eg delete files or send documents
via email or carry other executables as a
payload
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It can spread itself automatically over the
network from one computer to the next
Trojans
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Trojan horse is a program in which
harmful code is contained inside
apparently harmless program or data
so that it can get control and cause
damage
Hoaxes
Hoaxes may seem harmless, but they
do a great deal of damage to the
Internet as a whole
 Not only do they slow down traffic
and clog up email servers, but they
also cause people to panic
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Phishing
A form of identity theft
 an e-mail is sent that looks like it
comes from a legitimate company (eg
E-Bay) telling you that you must
update your records and verify your
username and password
 The site is really a fraud which
captures your information to steal
your identity, money, or whatever
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Spam
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The Internet version of junk mail
Over 50% of all emails today are junk
 Spamming is sending the same
message to a large number of mailing
lists or newsgroups without consent
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The term probably comes from a
famous Monty Python skit
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Often used to carry viruses, worms
etc
Spyware (or Adware)
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Program that secretly monitors your
actions on your computer without your
permission
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Sends this information to someone else
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Some are sinister and gather information
about e-mail addresses, passwords and
credit cards
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Some are used by software companies to
gather data about customers