![](media/image1.png){width="9.149305555555555in"
height="11.873611111111112in"}

  ---------------------------------------------------- -----------------------------------------------
  ![](media/image2.png){width="1.8958333333333333in"   :unwrapping new technologies
  height="1.6145833333333333in"}                       

  ---------------------------------------------------- -----------------------------------------------

-   Introduction (10 minutes)

-   Can You Hear Me Now: new waves in audio and video (25 minutes)

-   Blackberry Thumb: instant messaging, chat, and SMS (20 minutes)

-   I Always Feel Like Somebody's Watching Me: spyware and other malware
    (25 minutes)

-   Alphabet Soup: wireless standards (25 minutes)

-   Break (15 minutes)

-   Faster Than a Speeding Bullet! internet2 (20 minutes)

-   ![](media/image3.png){width="3.625in" height="3.125in"}Let My
    Software Go: the open source software movement (10 minutes)

-   I Know What You Took Last Night: radio frequency identifiers (RFID)
    (20 minutes)

-   Technolust: foxy new equipment (15 minutes)

-   Web Gone Wild: wikis, rss, blogs, and social networking software (60
    minutes)

-   Conclusion, questions, evaluations (15 minutes)

![](media/image4.png){width="5.999305555555556in"
height="7.441666666666666in"}Can You Hear Me Now:

new waves in audio and video

  ----------------------------------------------------- ------------------------------------------------
  ![](media/image5.jpeg){width="1.2673611111111112in"   Podcasting
  height="1.3625in"}                                    

  ----------------------------------------------------- ------------------------------------------------

**Podcasting** is a method of publishing audio programs via the
Internet, allowing users to subscribe to a feed of new files (usually
MP3s). It became popular in late 2004, largely due to automatic
downloading of audio onto portable players or personal computers.
Podcasting is distinct from other types of online media delivery because
of its subscription model, which uses a feed (such as RSS or Atom) to
deliver an enclosed file. Podcasting enables independent producers to
create self-published, syndicated "radio shows," and gives broadcast
radio programs a new distribution method. Listeners may subscribe to
feeds using "podcatching" software (a type of aggregator), which
periodically checks for and downloads new content automatically. Most
podcatching software enables the user to copy podcasts to portable music
players. Any digital audio player or computer with audio-playing
software can play podcasts. From the earliest RSS-enclosure tests, feeds
have been used to deliver video files as well as audio. By 2005 some
aggregators and mobile devices could receive and play video, but the
"podcast" name remained most associated with audio.

"Podcasting" is a portmanteau word that combines the words
"broadcasting" and "iPod." The term can be misleading since neither
podcasting nor listening to podcasts requires an iPod or any portable
player. Aware of that misleading association from the beginning, some
writers have suggested alternative names or reinterpretations of the
letters "p-o-d", without winning much of a following. Another
little-used alternative is "blogcasting", which implies content based
on, or similar in format to, blogs.

**Uses**

-   Distribution of ad hoc or informal "radio shows" such as Greg
    Schwartz's library-oriented show "Open Stacks."

-   Education: course lectures and hands-on language exercised can be
    podcast.

-   Religious groups podcast talks and sermons. This is known as
    *Godcasting*.

Adapted from the wikipedia article: http://en.wikipedia.org/wiki/Podcast

![](media/image6.png){width="5.8590277777777775in"
height="9.247222222222222in"}

#   {#section .unnumbered}

# Library-Related Podcasts

-   Open Stacks\
    Promoting information access and literacy for all.\
    http://openstacks.net/os/

# Health-Related Podcasts

-   Family Health\
    A daily series of 2 1/2 minute radio programs heard on over 250
    radio stations.Providing practical, easy-to-understand, honest
    health information on common health problems and the latest health
    care developments.\
    Topics have included side effects of medications, cause and
    treatment of insomnia, variocele and young men, good cholesterol
    numbers and heart attacks, and preventing skin injuries\
    http://fhradio.org/

-   NPR: Health and Science\
    From NPR: in-depth reports on medicine, the environment, space and
    more. The best of Morning Edition, All Things Considered and other
    award-winning NPR programs.\
    Stories from one episode included information about recovering from
    Hurricane Katrina and bird flu.\
    http://tinyurl.com/b7xza

-   Mayo Clinic -- Medical Edge Radio\
    Medical Edge Radio from Mayo Clinic \-- a daily 60-second health
    segment \-- features general health and people-focused stories
    covering medical breakthroughs and compelling health information.
    Mayo Clinic physicians rigorously evaluate all stories for medical
    validity and newsworthiness.\
    Topics have included wrist fractures in children, wrinkles, TPA for
    stroke, hypertension, and juvenile arthritis.\
    Available as podcast only through iTunes

-   The New England Journal of Medicine Audio Interviews\
    The New England Journal of Medicine (NEJM) Audio interview RSS feed.
    NEJM (http://www.nejm.org) is a weekly general medical journal that
    publishes new medical research findings, review articles, and
    editorial opinion on a wide variety of topics of importance to
    biomedical science and clinical practice.\
    http://tinyurl.com/af9cx

-   Blast Podcast health-related podcasts\
    http://tinyurl.com/7brxy

-   There are many other health-related podcasts available through
    iTunes by searching on "health" or "medicine."

![](media/image7.png){width="2.9791666666666665in"
height="2.5in"}**Podcatchers**

**\
for Windows**

-   iTunes\
    http://www.apple.com/itunes/

-   iPodder\
    http://ipodder.sourceforge.net/index.php

-   Doppler\
    http://www.dopplerradio.net/

-   Nimig\
    http://www.nimiq.nl/

-   Podfeeder (Currently for Windows only. OSX and Linux in the works.)\
    http://www.podfeeder.com/

**for Macintosh**

-   iTunes\
    http://www.apple.com/itunes/

-   iPodderX\
    http://ipodder.sourceforge.net/index.php

-   PlayPod\
    http://www.iggsoftware.com/playpod/

  ---------------------------------------- ------------------------------------------------
  ![](media/image8.png){width="1.8375in"   Vodcasting
  height="2.7583333333333333in"}           

  ---------------------------------------- ------------------------------------------------

**Vodcast** is an emerging term used for the online delivery of video on
demand content via RSS enclosures. The format is used by video weblogs
(also known as vlogs, vodding, vlogcasting, or vidcasting). The term is
an evolution specialized for video, coming from the generally
audio-based \"podcast.\"

Vodcast Resources

**Directories**

-   Vodcasts.tv\
    http://www.vodcasts.tv

-   Tech Shows\
    http://www.filefarmer.com/techshows/

-   iTunes\
    http://www.apple.com/itunes/

Adapted from the wikipedia article: http://en.wikipedia.org/wiki/Vodcast

  ---------------------------------------------------- -----------------------------------------------
  ![](media/image9.png){width="1.7902777777777779in"   VoIP\
  height="3.0375in"}                                   (Voice over IP)

  ---------------------------------------------------- -----------------------------------------------

**Voice over Internet Protocol** (also called **VoIP**, **IP
Telephony**, **Internet telephony**, and **Digital Phone**) is the
routing of voice conversations over the Internet or any other IP-based
network. The voice data flows over a general-purpose packet-switched
network, instead of traditional dedicated, circuit-switched voice
transmission lines.

  ---------------- ----------------------------------------------------------
  ***Definition:   *The difference between a packet switching network and a
  packet switching circuit switching network is that the former breaks
  and circuit      transmitted data into small, discrete groups of
  switching***     information that are individually routed between nodes
                   over conduits that may be shared by other nodes and the
                   latter establishes a direct and exclusive connection
                   between two the two nodes for the duration of the
                   exchange.*

  ---------------- ----------------------------------------------------------

Voice over IP traffic may be deployed on any IP network, including ones
lacking a connection to the rest of the Internet, for instance on a
private building-wide LAN.

![](media/image10.png){width="1.6597222222222223in"
height="5.495138888888889in"}**Advantages**

-   **Innovation**: VoIP developers respond to market pressures rather
    than at the pace of the International Telecommunications Union
    (ITU), resulting in speedy adoption of new or advanced features.

-   **Lower cost**: supporters claim that VoIP is cheaper than service
    from traditional services, and, in fact, VoIP *is* cheaper since
    calls, even international calls, may be considered to be *free*;
    however, many VoIP services require subscription to a data service
    also. For instance, a telecommunications service that advertises
    VoIP as free may require the user to obtain DSL service. For
    instance, Skype is considered, in some instance, to be free. The
    assumption is that the user already has access to a broadband
    connection, which may or may not be cheaper than traditional
    telephone service. For users who already *have* broadband service,
    this can be a major cost savings.

-   **Increased Functionality***.* VoIP makes easy some things that are
    difficult to impossible with traditional phone networks.

    -   Incoming phone calls are automatically routed to your VoIP
        phone, irrespective of where you are connected to the network.
        Take your VOIP phone with you on a trip, and anywhere you
        connect it to the Internet, you can receive your incoming calls.

    -   Call center agents using VoIP phones can easily work from
        anywhere with a good Internet \\be provided. This includes
        sending and receiving messages or data files in parallel with
        the voice conversation, audio conferencing, managing address
        books and passing information about whether others (e.g. friends
        or colleagues) are available online to interested parties.

**Disadvantages**

-   **Power dependence**: Traditional telephones are powered by
    telephone lines; therefore, they continue to work even when the
    power goes down. VoIP phones use broadband modems which go down when
    the power is out.

-   **Latency**: While packet switching takes best advantage of the
    structure of the internet, IP packets can often be lost or delayed
    between the end points of the communication.

-   ![](media/image11.png){width="3.1569444444444446in"
    height="3.3375in"}**911**: IP, as a non-geographically oriented
    technology, makes it difficult for emergency services to locate a
    caller who uses VoIP unless the caller can tell where she is.
    Moreover, some 911 callers may not even be connected to emergency
    dispatch if they dial the number on a VoIP phone. However, the US
    government has mandated that VoIP carriers must implement Enhanced
    911 (e911) services by a certain date. Some VoIP carriers, however,
    are appealing the deadline.

-   **Lack of Integration into global telephone number system**:\
    While the traditional Plain Old Telephone System (POTS) and mobile
    phone networks share a common global standard (E.164) which
    allocates and identifies any specific telephone line, there is no
    widely adopted similar standard for VoIP networks. Some allocate an
    E.164 number which can be used for VoIP as well as incoming/external
    calls. However, there are often different, incompatible schemes when
    calling between VoIP providers which use short codes that are
    provider specific.

Adapted from the wikipedia article: http://en.wikipedia.org/wiki/Voip

![](media/image12.png){width="4.15625in" height="6.666666666666667in"}

BlackBerry Thumb:\
instant messaging, chat, and SMS

#  

# 

+---------------------------+------------------------------------------+
| # ![](m                   | # Instant messaging (IM)                 |
| edia/image13.png){width=" |                                          |
| 2.279861111111111in" heig |                                          |
| ht="2.102777777777778in"} |                                          |
+---------------------------+------------------------------------------+

# Instant messaging

**Instant messaging** is the act of instantly communicating between two
or more people over a network such as the Internet.

## Overview

Instant messaging requires the use of a client program that hooks up an
instant messaging service and differs from e-mail in that conversations
are then able to happen in realtime. Most services offer a \"presence
awareness\" feature, indicating whether people on one\'s list of
contacts are currently online and available to chat. This may be called
a \'Buddy List\'. In early instant messaging programs, each letter
appeared as it was typed, and when letters were deleted to correct typos
this was also seen in real time. This made it more like a telephone
conversation than exchanging letters. In modern instant messenging
programs, the other party in the conversation generally only sees each
line of text right after a new line is started. Most instant messaging
applications also include the ability to set a status message, roughly
analogous to the message on a telephone answering machine.

Popular instant messaging services on the public Internet include Qnext,
MSN Messenger, AOL Instant Messenger, Yahoo! Messenger, Google Talk,
.NET Messenger Service, Jabber and ICQ. These services owe many ideas to
an older (and still popular) online chat medium known as Internet Relay
Chat (IRC).

In early instant messaging programs each character appeared as it was
typed. The UNIX \"talk\" command shown in these screenshots was popular
in the 1980s and early 1990s.

### History

An early form of instant messaging was implemented on the PLATO system
in the early 1970s. Later the UNIX/LINUX \"talk\" instant messaging
system was widely used by engineers and academics in the 1980s and 1990s
to communicate across the internet. ICQ was the first general instant
messenger introduced for non-UNIX/LINUX computers in November 1996.
After its introduction, a number of variations of instant messaging have
arisen in parallel in many places, each with its own protocol. This has
led to users running many instant messaging applications simultaneously
to be available on several networks. Alternatively they could use a
client which supports many protocols, such as Gaim, Trillian or Jabber
clients.

Recently, many instant messaging services have begun to offer video
conferencing features, Voice Over IP (VoIP), and web conferencing
services have begun to integrate both video conferencing and instant
messaging capabilities. Hence, the boundaries among these media have
become blurred.

On December 19, 2002, AOL Time Warner announced that ICQ had been issued
a United States patent for instant messaging, but they also said that
they had no plans on enforcing their patent at the present time.

The term \"instant messenger\" is a Service Mark of AOL Time Warner and
may not be used in software not affiliated with AOL. For this reason,
the instant messaging client formerly known as GAIM or gAIM is now only
to be referred to as Gaim or gaim.

## Origin of term

The phrase \"instant message\" was devised by Paul M. A. Linebarger for
a gimmick in the science-fiction stories he wrote in the 1960s under the
pseudonym Cordwainer Smith. *His* instant messages were to be across
interstellar distances at speeds faster than that of light, and said to
be expensive so he could write plots concerning their unaffordability.
From there, the phrase was picked up by members of New England Science
Fiction Association, many of whom were computer professionals, for their
weekly mimeographed newsletter. The phrase may have come from there. It
should be noted that America Online did not originally refer to their
own IM service as an instant messenger. The early software releases
referred to it as \"FlashMail.\" Early users spoke of \"flashing\" one
another, which was probably one reason that the name was changed.

## Cooperation

There have been several attempts to create a unified standard for
instant messaging: IETF\'s SIP (Session Initiation Protocol) and SIMPLE
(SIP for Instant Messaging and Presence Leverage), APEX (Application
Exchange), Prim (Presence and Instant Messaging Protocol), the open
XML-based XMPP (Extensible Messaging and Presence Protocol), more
commonly known as Jabber and OMA\'s (Open Mobile Alliance) IMPS (Instant
Messaging and Presence Service) created specifically for mobile devices.

Most attempts at creating a unified standard for the major IM providers
(AOL, Yahoo! and Microsoft) have failed and each continues to use its
own proprietary protocol although on October 13, 2005 Microsoft and
Yahoo! announced that by Summer of 2006 they would interoperate.

There are two ways to to combine the many disparate protocols:

1.  One way is to combine the many disparate protocols inside the IM
    *client* application. Examples include Trillian, Zango Messenger,
    Gaim, Fire, Proteus, Miranda IM, Adium, Everybuddy, Ayttm, Kopete,
    Centericq, BitlBee, and IMVITE.

2.  ![](media/image14.png){width="2.279861111111111in"
    height="3.00625in"}The other way is to combine the many disparate
    protocols inside the IM *server* application. This approach moves
    the task of communicating to the other services to the server.
    Clients need not know or care about other IM protocols. This
    approach is popular in Jabber/XMPP protocol servers however the
    presently available server bridge modules are immature and limited
    with respect to the full capabilities of the IM systems they bridge
    to.

The IMPS standard mentioned earlier is part of a mobile telephone
industry initiative to bring instant messaging to mobile phones. The
Open Mobile Alliance took over the standards, originally called Wireless
Village, in November 2002. There is a free IMPS-based service called
Yamigo which allows instant messaging on mobile phones even if your
carrier doesn\'t provide its own Wireless Village service. Yamigo acts
as a standalone instant messaging network, but can also integrate with
ICQ, AIM, MSN, Yahoo and Jabber.

Some approaches, such as that adopted by the Sonork enterprise IM
software or the Jabber/XMPP network, allow organizations to create their
own private instant messaging network by enabling them to limit access
to the server (often with the IM network entirely behind their firewall)
and administer user permissions. Typically, a dedicated corporate IM
server has several advantages such as pre-populated contact lists,
integrated authentication, and better security and privacy.

Some networks have made changes to prevent them from being utilized by
such multi-network IM clients. For example, Trillian had to release
several revisions and patches to allow its users to access the MSN, AOL,
and Yahoo networks, after changes were made to these networks. The major
IM providers typically cite the need for formal agreements as well as
security concerns as reasons for making these changes.

Retrieved from \"http://en.wikipedia.org/wiki/Instant_messaging\"

# 

+-----------------------+----------------------------------------------+
| # ![](me              | # Short message service: (SMS)               |
| dia/image15.jpeg){wid |                                              |
| th="1.875in" height=" |                                              |
| 1.426388888888889in"} |                                              |
+-----------------------+----------------------------------------------+

**Short message service** (**SMS**) is a service available on most
digital mobile phones that permits the sending of short messages (also
known as **text messages**, **messages**, or more colloquially
**SMSes**, **texts** or even **txts**) between mobile phones, other
handheld devices and even landline telephones.

## History

The inventor of SMS is a Finnish civil servant by the name Matti
Makkonen who then worked for a state-owned postal and telecommunications
company Posti (Finland). He presented the idea in a pizzeria in
Copenhagen, during a conference of mobile phone communication\'s future
in fall of 1982. Today M. Makkonen is the CEO of Finnet. Initially
conceptualized as **Message Handling Services**, SMS was proposed to be
included in the GSM digital mobile phone standard as early as in 1984 by
the Nordic Countries (in GSM WP3, a group chaired by J. Audestad). SMS
was further discussed in the main GSM Group in February 1985 and it was
included in the draft GSM spec (GSM Doc.28-85) the same year. The
technical standard known today was largely created by IDEG\'s Draft
Group on Message Handling in 1987--1990, first chaired by Friedhelm
Hillebrand. The first commercial short message was sent on 3 December
1992 by Neil Papworth of Sema Group from a personal computer to Richard
Jarvis of Vodafone on the Vodafone GSM network in the United Kingdom.

SMS was originally designed as part of GSM, but is now available on a
wide range of networks, including 3G networks. However, not all text
messaging systems use SMS, and some notable alternate implementations of
the concept include J-Phone\'s *SkyMail* and NTT Docomo\'s *Short Mail*,
both in Japan. E-mail messaging from phones, as popularized by NTT
Docomo\'s i-mode and the RIM BlackBerry, also typically use standard
mail protocols such as SMTP over TCP/IP, not SMS.

+-----------+----------------------------------------------------------+
| ***Defini | ***GSM**: Global System for Mobile Communications, a     |
| tions:*** | mobile phone standard that has built in data             |
|           | communications: both voice and signaling are digital.    |
| ***GSM &  | GSM is a 2G technology.*                                 |
| 3G***     |                                                          |
|           | ***3G**: third generation mobile phone technology:       |
|           | includes both voice data and non-voice data such as      |
|           | information, email, instant messaging, music, and        |
|           | movies.*                                                 |
+-----------+----------------------------------------------------------+

## Popularity

Short message services are developing very rapidly throughout the world.
By mid-2004 texts were being sent at a rate of 500 billion messages per
annum. At an average cost of USD 0.10 per message, this generates
revenues in excess of 50 billion for mobile telephone operators and
represents close to 100 text messages for every person in the world.
Growth has been rapid; in 2001, 250 billion SMS messages were sent, in
2000 just 17 billion. SMS is particularly popular in Europe, Asia
(excluding Japan and Korea) and Australia. Popularity has grown to a
sufficient extent that the term *texting* (used as a verb meaning the
act of cell phone users sending SMS text messages back and forth) has
entered the common lexicon. In China, SMS is very popular, and has
brought service providers large profit (18 billion SMS were sent in
2001).

SMS messages are particularly popular amongst young urbanites. In many
markets, the service is comparatively cheap. For example, in Australia a
message typically costs between AUD 0.20 and AUD 0.25 to send, compared
to a voice call, which costs anywhere between AUD 0.40 and AUD 2.00 per
minute.

The most frequent texters are found in south-east Asia. In Singapore,
hundreds of messages can be sent per month for free, after which
messages cost between SGD 0.05 and SGD 0.07 each to send. The same
pricing format is followed in the Philippines where the average user
sent 2,300 messages in 2003, making it the world\'s most avid texting
nation. SMS is a part in almost all marketing campaigns, advocacy, and
entertainment. In fact, SMS is so inexpensive (messages cost PHP 1.00
(about USD 0.02) to send), influential, powerful, and addictive for
Filipinos that several local dotcoms like Chikka Messenger, GoFISH
Mobile, and Bidshot now fully utilize SMS for their services.

Europe follows next behind Asia in terms of the popularity of texting.
In 2003, an average of 16 billion messages were sent each month. Users
in Spain sent a little more than fifty messages per month on average in
2003. In Italy, Germany and the United Kingdom the figure was around
35--40 texts per month. In each of these countries the cost of sending a
text varies from as little as £0.03 - £0.18 depending on the payment
plan. Curiously France has not taken to texting in the same way, sending
just under 20 texts on average per user per month. France has the same
GSM technology as other European countries so the uptake is not hampered
by technical restrictions. Part of the reason for the lack of uptake may
be due higher prices due to weak competition in the mobile market - the
key player Orange is owned by subsidized France Télécom. However some
telecom analysts suggest that this factor has dissipated in recent years
and say that the reason may be cultural - text messaging is associated
with a fast pace of life and France is more reluctant than others to
dispense with its traditions.

![](media/image16.png){width="2.9in" height="6.252777777777778in"}In the
US, however, the appeal of SMS is even more limited. Although a SMS
usually costs only USD 0.05 (many providers also offer monthly
allotments), only 13 messages were sent by the average user in 2003. The
reasons for this are varied -- many users have unlimited
\"mobile-to-mobile\" minutes, high monthly minute allotments, or
unlimited service. Moreover, push to talk services offer the instant
connectivity of SMS service and are typically unlimited. Further the
integration between competing providers and technologies necessary for
cross-network texting has only been available recently. SMS is also
typically an opt-in service in the United States - thus sending a
message is much less a guarantee of receipt than in other countries.
However the recent addition of AT&T-powered SMS voting on the television
program *American Idol* has introduced many Americans to SMS, and usage
is on the rise.

In addition to SMS voting, a different phenomenon has risen in more cell
phone saturated countries. In Finland some TV channels began \"SMS
Chat\", which involved sending short messages to a phone number, and
after a certain while the message would be shown on TV. Chats are always
moderated, which prevents sending harmful material to the channel. The
craze soon became popular and evolved into games, first slow-paced quiz
and strategy games. After a while, faster paced games designed for
television and SMS control were designed. Games tend to involve
registering one\'s nickname, and after that sending SMSs for controlling
a character on screen. Messages usually cost 0.05 to 0.86 euros apiece,
and games can require sending dozens of messages. In December 2003
Finnish TV-channel MTV3 put on air Santa Claus character reading aloud
messages sent by SMS. Some customers were later accused of \"hacking\"
after they discovered a way to control Santa\'s speech synthesizer. More
recent late-night attractions on the same channel include \"Beach
Volley\", in which bikini-clad female hostess blocks balls \"shot\" with
text-messages. On March 12 2004, first entirely \"interactive\"
TV-channel \"VIISI\" began its operation in Finland. That did not last
long, though, as SBS Finland Oy took over the channel and made it a
music channel named \"The Voice\" in November 2004.

Text messaging is also popular in Japan. However, it is known by
different names depending on the mobile service. With NTT DoCoMo, it is
known as \"i-mode mail.\" With AU, it is known as \"C-Mail.\" Mobile
e-mail is usually the norm when sending messages between phones with
different services, but between phones using the same service, text
messaging is more prevalent.

A few widely publicized speed contests have been held between expert
Morse code operators and expert SMS users (see references). Morse code
has consistently won the contests, leading to speculation that cellphone
manufacturers may eventually build a Morse code interface into
cellphones. The interface would automatically translate the Morse code
input into text so that it could be sent to any SMS-capable cellphone so
therefore the receiver of the message need not know Morse code to read
it. Other speculated applications include taking an existing assistive
application of Morse code and using the vibrating alert feature on the
cellphone to translate SMS messages to Morse code for silent, hands free
\"reading\" of the incoming messages. Several cellphones already have
informative audible Morse code ring tones and alert messages, for
example: many Nokia cellphones have an option to beep SMS in Morse code
when it receives an SMS text message. There are third party applications
already available for some cellphones that allow Morse input for SMS
(see references).

An increasing trend towards spamming cell phone users through SMS has
prompted cellular service carriers to take steps against the practice,
before it becomes a widespread problem. No major spamming incidents
involving SMS have been reported as of October 2003, but the existence
of cell-phone spam has already been noted by industry watchdogs,
including *Consumer Reports* magazine.

## Txt speak

Because of the limited message lengths and tiny user interface of mobile
phones, SMS users commonly make extensive use of abbreviations,
particularly the use of numbers for words (for example, \"4\" in place
of the word \"for\"), the omission of vowels, as in the phrase \"txt
msg\", or the replacement of spaces with capitalization, such as
\"ThisIsVeryCool\". To avoid the even more limited message lengths
allowed when using Cyrillic or Greek letters, some Eastern Europeans use
the Latin alphabet for their own language.

Historically, this language developed out of shorthand used in chatrooms
on the Internet, where users would abbreviate some words to allow a
response to be typed more quickly. However, this became much more
pronounced in SMS, where mobile phone users don\'t generally have fully
access to a QWERTY keyboard as chatroom users did, and more effort is
required to type each character.

In Mandarin Chinese, numbers that sound similar to words are used in
place of those words. For example, the numbers 521 in Chinese (\"wu er
yi\") sound like the words for \"I love you\" (\"wo ai ni\"). The
sequence 748 (\"qi si ba\") sounds like the curse for \"drop dead\".

Predictive text software that attempts to guess words (AOL\'s T9) or
letters (Eatoni\'s LetterWise) reduces the labor of time-consuming
input. This makes abbreviations not only less necessary, but slower to
type than regular words which are in the software\'s dictionary. However
it does make the texts longer, often requiring the text message to be
sent in multiple parts and therefore costing more to send.

An example of some is the following passage translated from William
Shakespeare\'s A Midsummer Night\'s Dream: If we shadwoes ave ofendd.
Thnk bt ths & al is mnded. That u ave but slumer'd ere; while thse
visions did appr; & this wk & idel theme; no mre yielding bt a dream.
Gentles, do nt reprehend; if u pardon we wil mend; & I am honst Puck;

## Social Impact of SMS

SMS has caused subtle but interesting changes in society since it became
popular. News worthy events include (in chronological order):

-   In January 2001, Joseph Estrada was forced to resign from the post
    of president of the Philippines. The popular campaign against him
    was widely reported to have been co-ordinated with SMS *chain
    letters*.

```{=html}
<!-- -->
```
-   In July 2001, Malaysia\'s government decreed that an Islamic divorce
    (which consists of saying \"I divorce you\" three times in
    succession) was not valid if sent by SMS.

```{=html}
<!-- -->
```
-   A cheating scheme was uncovered during final-exam week at the
    University of Maryland, College Park in December 2002, when a dozen
    students were caught cheating on an accounting exam through the use
    of text messages on their cell phones. Similarly, Hitotsubashi
    University in Japan failed 26 students in December 2002 for
    receiving e-mailed exam answers on their cell phones.

```{=html}
<!-- -->
```
-   In October 2003, a Filipino immigrant living in Belgium was arrested
    by police after a friend sent him a joke SMS pretending to be the
    world\'s most wanted terrorist. The SMS read \'I was wondering if I
    can stay with you for a couple of days. Everybody\'s so angry at me.
    And I really need a friend. Yours truly, Osama bin Laden.\' .

```{=html}
<!-- -->
```
-   During the 2004 Philippine presidential elections, SMS was a popular
    form of electoral campaigning for and against candidates such as
    incumbent president Gloria Macapagal-Arroyo and main contender
    Fernando Poe, Jr..

```{=html}
<!-- -->
```
-   In June 2004, a British punk rock fan was questioned by police,
    regarding a text message containing lyrics from \"Tommy Gun\" by The
    Clash, \"How about this for Tommy Gun? OK - so let\'s agree about
    the price and make it one jet airliner for 10 prisoners.\".

```{=html}
<!-- -->
```
-   In August 2005, a SMS chat sculpture was installed at the annual
    diploma exhibition of Dresden\'s University of Art HfBK. The artist
    Matthias Haase explores today\'s means of social interaction.
    Visitors may participate in the art work by sending a text message
    to the sculpture, which projectes the SMS onto a screen 1, SMS chat
    sculpture.

```{=html}
<!-- -->
```
-   A hoax involving SMS following the Helios Airways Flight 522 plane
    crash on August 14, 2005: News media widely reported that shortly
    before the crash a passenger sent a SMS transmission indicating that
    the pilot had become blue in the face, or roughly translated as
    \"The pilot is dead. Farewell, my cousin, here we\'re frozen.\"
    Police later arrested Nektarios-Sotirios Voutas, a 32 year-old
    private employee from Thessaloniki who admitted that he had made up
    the story and given several interviews in order to get attention.

```{=html}
<!-- -->
```
-   During Hurricane Katrina many residents, unable to make contact with
    relatives/friends using traditonal landline phones, communicated via
    text messaging.

Adapted from \"http://en.wikipedia.org/wiki/Short_message_service\"

![](media/image17.png){width="3.5659722222222223in" height="8.3375in"}

I Always Feel Like Somebody's Watching Me:

spyware and other malware

  ----------------------------------------------------- ------------------------------------------------
  ![](media/image18.png){width="1.8479166666666667in"   The Software Who Loved Me:\
  height="3.109722222222222in"}                         spyware

  ----------------------------------------------------- ------------------------------------------------

**Spyware** is a broad category of malicious software intended to
intercept or take partial control of a computer\'s operation without the
user\'s informed consent. While the term taken literally suggests
software that surreptitiously monitors the user, it has come to refer
more broadly to software that subverts the computer\'s operation for the
benefit of a third party.

Spyware differs from viruses and worms in that it does not usually
self-replicate. Like many recent viruses, spyware is designed to exploit
infected computers for commercial gain. Typical tactics furthering this
goal include delivery of unsolicited pop-up advertisements; theft of
personal information (including financial information such as credit
card numbers); monitoring of Web-browsing activity for marketing
purposes; or routing of HTTP requests to advertising sites. In some
cases, spyware may be used to verify compliance with a software license
agreement (or EULA).

As of 2005, spyware is only a common problem for computers running
Microsoft Windows operating systems. Some worms or rootkits able to
attack Linux and other Unix platforms include spyware-like functions,
and keyloggers or other similar monitoring software exists for nearly
every operating system.

According to an October 2004 study by America Online and the National
Cyber-Security Alliance, 80% of surveyed users\' computers had some form
of spyware, with an average of 93 spyware components per computer. 89%
of surveyed users with spyware reported that they did not know of its
presence, and 95% reported that they had not given permission for it to
be installed.

## Spyware, \"adware\", and tracking

The term *adware* frequently refers to any software which displays
advertisements, whether or not it does so with the user\'s consent.
Programs such as the Eudora mail client display advertisements as an
alternative to shareware registration fees. These classify as \"adware\"
in the sense of advertising-supported software, but not as spyware. They
do not operate surreptitiously or mislead the user.

Many of the programs frequently classified as spyware function as
*adware* in a different sense: their chief observed behavior consists of
displaying advertising. Claria Corporation\'s Gator Software provides an
example of this sort of program. Visited Web sites frequently install
Gator on client machines in a surreptitious manner, and it directs
revenue to the installing site and to Claria by displaying
advertisements to the user. The user\'s experience is that their
computer begins displaying a large number of pop-up advertisements.

Other spyware behaviors, such as reporting on Web sites the user visits,
frequently accompany the displaying of advertisements. The goal of
monitoring Web activity is to build up a marketing profile on the user
in order to sell \"targeted\" advertisement impressions. The prevalence
of spyware has cast suspicion upon other programs that track Web
browsing, even for statistical or research purposes. Some observers
describe the Alexa Toolbar, an Internet Explorer plug-in published by
Amazon.com, as spyware (and some anti-spyware programs report it as
such) although many users choose to install it.

## ![](media/image19.png){width="1.9270833333333333in" height="4.3125in"}Routes of infection

Spyware does not directly spread in the manner of a computer virus or
worm: generally, an infected system does not attempt to transmit the
infection to other computers. Instead, spyware gets on a system through
deception of the user or through exploitation of software
vulnerabilities.

The most direct route by which spyware can get on a computer is for the
user to install it. However, users are unlikely to install software if
they know that it may disrupt their working environment and compromise
their privacy. So many spyware programs deceive the user, either by
piggybacking on a piece of desirable software, or by tricking the user
to do something that installs the software without realizing it.

Classically, the definition of a Trojan horse involves something
dangerous that comes in the guise of something desirable. Some spyware
programs are distributed in just this manner. The distributor of spyware
presents the program as a useful utility---for instance as a \"Web
accelerator\" or as a helpful software agent. Users download and install
the software, only to find out later that it can cause harm. For
example, Bonzi Buddy, a spyware program targeted at children, claims
that:

> *He will explore the Internet with you as your very own friend and
> sidekick! He can talk, walk, joke, browse, search, e-mail, and
> download like no other friend you\'ve ever had! He even has the
> ability to compare prices on the products you love and help you save
> money! Best of all, he\'s FREE!*

![](media/image20.png){width="3.2979166666666666in"
height="3.904861111111111in"}Spyware can also come bundled with
shareware or other downloadable software. The user downloads a
program---for instance, a music program or a file-trading utility---and
installs it; the installer additionally installs the spyware. Although
the desirable software itself may do no harm, the bundled spyware does.
In some cases, spyware authors have paid shareware authors to bundle
spyware with their software, as with the *Gator* spyware now marketed by
Claria. In other cases, spyware authors have repackaged desirable
software with installers that add spyware.

A third way of distributing spyware involves tricking users by
manipulating security features designed to prevent unwanted
installations. The design of the Internet Explorer Web browser is
intended *not* to allow Web sites to initiate an unwanted download.
Instead, a user action, such as clicking on a link, has to trigger a
download. However, links can prove deceptive: for instance, a pop-up ad
may appear like a standard Windows dialog box. The box contains a
message such as \"Would you like to optimize your Internet access?\"
with links which look like buttons reading *Yes* and *No*. No matter
which \"button\" the user presses, a download starts, placing the
spyware on the user\'s system. Later versions of Internet Explorer offer
fewer avenues for this attack.

Some spyware authors infect a system by attacking security holes in the
Web browser or in other software. When the user navigates to a Web page
controlled by the spyware author, the page contains code which attacks
the browser and forces the download and install of spyware. This has
become known as a \"drive-by download\", by analogy to drive-by shooting
in which the user is a hapless bystander. Common attacks target security
vulnerabilities in Internet Explorer and in the Microsoft Java runtime.
Given that Internet Explorer is still the most widely used browser and
that many users\' systems are not up to date, it creates an attractive
entry point for the less scrupulous advertisers.

Internet Explorer also serves as a point of attachment for these
programs, which install themselves as Browser Helper Object plugins.

In a few cases, a worm or virus has delivered a payload of spyware. For
instance, some attackers used the W32.Spybot.Worm worm to install
spyware that popped up pornographic ads on the infected system\'s
screen. By directing traffic to ads set up to channel funds to the
spyware authors, they can profit even by such clearly illegal behavior.

## Effects and behaviors

Windows-based computers can rapidly accumulate a great many spyware
components. The consequences of a moderate to severe spyware infection
(privacy issues aside) generally include a substantial loss of system
performance (over 50% for bad infections), and major stability issues
(crashes and hangs). Difficulty in connecting to the Internet is another
common symptom.

Spyware infection occasions more visits to professional computer
repairers than any other single cause. In many cases, the user has no
awareness of spyware and assumes that the system performance, stability,
and/or connectivity issues relate to hardware, to Windows installation
problems, or to a virus. To have spyware professionally removed
typically costs about \$50 US. Some owners of badly infected systems
resort to buying an entire new computer system because the existing
system \"has become too slow\". For badly infected systems, a clean
reinstall may be required to restore the system to a working order---a
time-consuming project even for experienced users.

Only rarely does a single piece of software render a computer unusable.
Rather, a computer rarely has only one infection. As the 2004 AOL study
noted, if a computer has any spyware at all, it typically has dozens of
different pieces installed. The cumulative effect, and the interactions
between spyware components, typically cause the stereotypical symptoms
reported by users---a computer which slows to a crawl, overwhelmed by
the many parasitic processes running on it. Moreover, some types of
spyware disable software firewalls and anti-virus software, and reduce
browser security settings, opening the system to further opportunistic
infections, much like an immune deficiency disease. There are also
documented cases where a spyware program disabled other spyware programs
created by the competitors.

### ![](media/image21.png){width="6.0in" height="4.091666666666667in"}Advertisements

The most visible behavior of many spyware programs is to display
advertisements. Some programs simply display pop-up ads on a regular
basis \-- for instance, one every several minutes, or one when the user
opens a new browser window. Others display ads in response to specific
sites that the user visits. Spyware operators present this feature as
desirable to advertisers, who may buy ad placement in pop-ups displayed
when the user visits a particular site. It is also one of the purposes
for which spyware programs gather information on user behavior.

Pop-up advertisements lead to some of users\' most common complaints
about spyware. The first is simply that the computer can become
overwhelmed downloading or displaying ads. An infected computer rarely
has only one spyware component installed \-- they more often number in
the dozens \-- and so while a single program might display ads only
infrequently, the cumulative effect is overwhelming.

Irritating or offensive advertisements are another common complaint. As
with many banner ads, many spyware advertisements are animated,
flickering banners designed to catch the eye \-- that is, they are
highly visually distracting. Pop-up ads for pornography are often
displayed indiscriminately, including when children are using the
computer \-- possibly in violation of laws on the subject.

A further issue in the case of some spyware programs has to do with the
replacement of banner ads on viewed web sites. Spyware which acts as a
web proxy or a Browser Helper Object can replace references to a site\'s
own advertisements (which fund the site) with advertisements which
instead fund the spyware operator. This cuts into the margins of
advertising-funded Web sites.

### \"Stealware\" and affiliate fraud

A few spyware vendors, notably WhenU and 180 Solutions, have written
what the New York Times has dubbed \"stealware\", and spyware researcher
Ben Edelman terms *affiliate fraud*, also known as click fraud. These
redirect the payment of affiliate marketing revenues from the legitimate
affiliate to the spyware vendor.

Affiliate marketing networks work by tracking users who follow an
advertisement from an \"affiliate\" and subsequently purchase something
from the advertised Web site. Online merchants such as eBay and Dell are
among the larger companies which use affiliate marketing. In order for
affiliate marketing to work, the affiliate places a tag such as a cookie
or a session variable on the user\'s request, which the merchant
associates with any purchases made. The affiliate then receives a small
commission.

Spyware which attacks affiliate networks does so by placing the spyware
operator\'s affiliate tag on the user\'s activity \-- replacing any
other tag, if there is one. This harms just about everyone involved in
the transaction other than the spyware operator. The user is harmed by
having their choices thwarted. A legitimate affiliate is harmed by
having their earned income redirected to the spyware operator. Affiliate
marketing networks are harmed by the degradation of their reputation.
Vendors are harmed by having to pay out affiliate revenues to an
\"affiliate\" who did not earn them according to contract.

Affiliate fraud is a violation of the terms of service of most affiliate
marketing networks. As a result, spyware operators such as WhenU and 180
Solutions have been terminated from affiliate networks including
LinkShare and ShareSale.

### Spyware and cookies

Anti-spyware programs often report Web advertisers\' HTTP cookies as
spyware. Cookies are not software of any sort---they are variables set
by Web sites (including advertisers) which can be used to track
Web-browsing activity, for instance to maintain a \"shopping cart\" for
an online store or to maintain consistent user settings on a search
engine.

Cookies can only be accessed by the Web site that sets them. In the case
of cookies associated with advertisements, this is generally *not* the
Web site that the user intended to visit, but a third-party site
referenced by a banner ad image. Some Web browsers and privacy tools
offer to reject cookies from sites other than the one that the user
requested.

Advertisers use cookies to track people\'s browsing among various sites
carrying ads from the same firm and thus to build up a marketing profile
of the person or family using the computer. It is for this reason that
many users object to such cookies, and that anti-spyware programs offer
to remove them.

### Typical examples of spyware

A few examples of common spyware programs may serve to illustrate the
diversity of behaviors found in these attacks.

**CoolWebSearch**, a group of programs, installs through the
exploitation of Internet Explorer vulnerabilities. The programs direct
traffic to advertisements on Web sites including *coolwebsearch.com*. To
this end, they display pop-up ads, rewrite search engine results, and
alter the infected computer\'s hosts file to direct DNS lookups to these
sites.

**Internet Optimizer**, also known as **DyFuCa**, redirects Internet
Explorer error pages to advertising. When users follow a broken link or
enter an erroneous URL, they see a page of advertisements. However,
because password-protected Web sites (HTTP Basic authentication) use the
same mechanism as HTTP errors, Internet Optimizer makes it impossible
for the user to access password-protected sites.

**180 Solutions** transmits extensive information to advertisers about
the Web sites which users visit. It also alters HTTP requests for
affiliate advertisements linked from a Web site, so that the
advertisements make unearned profit for the 180 Solutions company. It
opens pop-up ads that cover over the Web sites of competing companies.

**HuntBar**, aka **WinTools** or **Adware.Websearch**, is a small family
of spyware programs distributed by Traffic Syndicate. It is installed by
ActiveX drive-by download at affiliate Web sites, or by advertisements
displayed by other spyware programs \-- an example of how spyware can
install more spyware. These programs add toolbars to Internet Explorer,
track Web browsing behavior, redirect affiliate references, and display
advertisements.

## Remedies and prevention

As the spyware threat has worsened, a number of techniques have emerged
to counteract it. These include programs designed to remove or to block
spyware, as well as various user practices which reduce the chance of
getting spyware on a system.

Nonetheless, spyware remains a costly problem. When a large number of
pieces of spyware have infected a Windows computer, the only remedy may
involve backing up user data, and fully reinstalling the operating
system.

### Anti-spyware programs

Many programmers and commercial firms have released products designed to
remove or block spyware. Steve Gibson\'s *OptOut*, mentioned above,
pioneered a growing category. Programs such as Lavasoft\'s *Ad-Aware*
and Patrick Kolla\'s *Spybot - Search & Destroy* rapidly gained
popularity as effective tools to remove, and in some cases intercept,
spyware programs. More recently Microsoft acquired the *GIANT
Anti-Spyware* software, rebadging it as *Windows AntiSpyware Beta* and
releasing it as a free download for Windows XP, Windows 2000, and
Windows 2003 users. The *Windows AntiSpyware Beta* is a time-limited
program, set to expire at the end of December 2005. The GIANT
AntiSpyware database was also licensed to Sunbelt Software for its
CounterSpy home product. Another popular spyware remover program is
SpySweeper 4.0 from Webroot. Webroot received the #1 rated spyware
remover program by PC Magazine in their 2005 security issue.

Major anti-virus firms such as Symantec, McAfee and Sophos have come
later to the table, adding anti-spyware features to their existing
anti-virus products. Early on, anti-virus firms expressed reluctance to
add anti-spyware functions, citing lawsuits brought by spyware authors
against the authors of web sites and programs which described their
products as \"spyware\". However, recent versions of these major firms\'
home and business anti-virus products do include anti-spyware functions,
albeit treated differently from viruses. Symantec Anti-Virus, for
instance, categorizes spyware programs as \"extended threats\" and does
not offer real-time protection from them as it does for viruses.

Anti-spyware programs can combat spyware in two ways: *real-time
protection*, which prevents spyware from being installed, and *scanning
and removal* of spyware. Scanning and removal is usually simpler, and so
many more programs have become available which do so. The program
inspects the contents of the Windows registry, the operating system
files, and installed programs, and removes files and entries which match
a list of known spyware components. Real-time protection from spyware
works identically to real-time anti-virus protection: the software scans
incoming network data and disk files at download time, and blocks the
activity of components known to represent spyware. In some cases, it may
also intercept attempts to install start-up items or to modify browser
settings.

Earlier versions of anti-spyware programs focused chiefly on scanning
and removal. Javacool Software\'s SpywareBlaster was one of the first to
offer real-time protection, blocking the installation of ActiveX-based
and other spyware programs. To date, other programs such as Ad-Aware and
Windows AntiSpyware now combine the two approaches, while SpywareBlaster
remains focused on real-time protection.

If a spyware program is not blocked and manages to get itself installed,
it may resist attempts to terminate or uninstall it. Some programs work
in pairs: when an anti-spyware scanner (or the user) terminates one
running process, the other one respawns the killed program. Likewise,
some spyware will detect attempts to remove registry keys and
immediately add them again. Usually, booting the infected computer in
safe mode allows an anti-spyware program a better chance of removing
persistent spyware.

Malicious programmers have released a large number of fake anti-spyware
programs, and widely distributed Web banner ads now spuriously warn
users that their computers have been infected with spyware, directing
them to purchase programs which do not actually remove spyware---or
worse, may add more spyware of their own.

### Security practices

To deter spyware, computer users have found a number of techniques
useful in addition to installing anti-spyware software.

Many systems install a web browser other than Microsoft\'s Internet
Explorer (IE), such as Opera or Mozilla Firefox. While other web
browsers have also had security vulnerabilities, Internet Explorer has
contributed to the spyware problem in two ways: first, many spyware
programs hook themselves into IE\'s functionality (as a Browser Helper
Object or a toolbar); second, malicious Web advertisers have frequently
used security holes in Internet Explorer to force the browser to
download spyware. Many users of non-IE browsers on Windows report that
they have switched from IE because of security concerns, including
concerns about spyware.

Internet Explorer users can improve security by keeping up-to-date on
security patches, and by altering settings in the browser ---
particularly those disabling scripting technologies such as ActiveX.
(However, Web sites that make use of ActiveX will not work in this
scenario.) The version of IE which comes with Windows XP Service Pack 2
also has substantially-improved security defaults, although spyware
infections can still occur.

Some Internet sites --- particularly colleges and universities --- have
taken a different approach to blocking spyware: they use their network
firewalls and web proxies to block access to Web sites known to install
spyware. On March 31, 2005, Cornell University\'s Information Technology
department released a report detailing the behavior of one particular
piece of proxy-based spyware, *Marketscore*, and the steps the
university took to intercept it. Many other educational institutions
have taken similar steps against Marketscore and other spyware. Spyware
programs which redirect network traffic cause greater technical-support
problems than programs which merely display ads or monitor users\'
behavior, and so may attract institutional attention more readily.

Spyware may get installed via certain shareware programs offered for
download. Downloading programs only from reputable sources can provide
some protection from this source of attack. One site, CleanSoftware.org,
founded as an alternative to other popular Windows software sites,
offers only software verified not to contain \"nasties\" such as
spyware. Recently, C\|Net revamped their download directory and will
only keep files that pass inspection by Ad-Aware and Spyware Doctor.

## Must to Avoid!

-   Atomic clock sync

-   Bearshare

-   Bonzi Buddy

-   Cliprex DVD player

-   DivX (except for the paid version, and the \'standard\' version
    without the encoder. DivX announced removal of GAIN software from
    version 5.2)

-   Dope Wars

-   Download Accelerator Pro

-   ErrorGuard

-   FlashGet (free version)

-   Gator

-   Grokster

-   Kazaa

-   Messenger Plus (optional) (This has caused controversy with
    Microsoft as it\'s anti-spyware program identifies MsgPlus as the
    spyware, not C2.Lop)

-   Napster Light (when not entering credit card information)

-   RadLight

-   WeatherBug

-   WildTangent

### Gotten Their Act Together

-   AOL Instant Messenger

-   EDonkey2000

-   LimeWire (spyware was included in all versions other than the
    non-windows versions, the paid versions, and the free versions after
    3.9.3)

### Guides (URLs available at http://en.wikipedia.org/wiki/Spyware)

-   Magoo\'s Guide to Eliminating Spyware --- Infomation on how to get
    rid of spyware and keep it from returning

-   CareOfWindowsXP Spyware guide --- Advice on spyware for beginners

-   Bleeping Computer Spyware Removal Tutorials --- tutorials for
    HijackThis, Spybot, and Ad-Aware.

-   Dedicated 2 spyware --- Reviews of Antispyware programs, Corrupt
    anti-spyware list, tutorials, Library of files and encyclopedia of
    parasites.

### Prevention

-   How Spyware And The Weapons Against It Are Evolving --- Article
    discussing why the spyware problem has grown and possible remedies

Adapted from \"http://en.wikipedia.org/wiki/Spyware\"

+---------------------+------------------------------------------------+
| ![](media/image22.  | Odd Jobs:                                      |
| png){width="1.25in" |                                                |
| height="3.6         | Other Malware                                  |
| 458333333333335in"} |                                                |
+---------------------+------------------------------------------------+

## Classes of malicious software

Two common types of malware are viruses and worms. These types of
programs have in common that they are both able to self-replicate; they
can spread (possibly modified) copies of themselves. Not every program
that copies itself is a virus or worm; for instance, backup software may
copy itself to other media as part of a system backup. To be classified
as a virus or worm, at least some of these copies have to be able to
replicate themselves too, such that the virus or worm can propagate
itself. The difference between a virus and a worm is that a worm
operates more or less independently of other files, whereas a virus
depends on hosts to spread itself.

### Virus

Viruses have used many sorts of hosts. When computer viruses first
originated, common targets were executable files that are part of
application programs and the boot sectors of floppy disks. More
recently, most viruses have embedded themselves in e-mail as Email
attachments, depending on a curious user opening the viral attachment.
In the case of executable files, the infection routine of the virus
arranges that when the host code is executed, the viral code gets
executed as well. Normally, the host program keeps functioning after it
is infected by the virus. Some viruses overwrite other programs with
copies of themselves which destroys them altogether. Viruses can spread
across computers when the software or document they\'ve attached
themselves to is transferred from one computer to the other.

### Worms

Computer worms are similar to viruses but are stand-alone software and
thus do not require host files (or other types of host code) to spread
themselves. They do modify their host operating system, however, at
least to the extent that they are started as part of the boot process.
To spread, worms either exploit some vulnerability of the target system
or use some kind of social engineering to trick users into executing
them.

### Wabbit

A third, uncommon, type of self-replicating malware is the wabbit.
Unlike viruses, wabbits do not infect host programs or documents. Unlike
worms, wabbits do not use network functionality in order to spread to
other computers. An example of a simple wabbit is a fork bomb.

### ![](media/image23.png){width="2.9972222222222222in" height="3.152083333333333in"}Trojan

A trojan horse program is a harmful piece of software that is disguised
as legitimate software. Trojan horses cannot replicate themselves, in
contrast to viruses or worms. A trojan horse can be deliberately
attached to otherwise useful software by a programmer, or it can be
spread by tricking users into believing that it is useful. To complicate
matters, some trojan horses can spread or activate other malware, such
as viruses. These programs are called \'droppers\'. A common aftermath
is the Trojan attracting a large amount of adware/spyware, causing lots
of popups and web browser instability.

### Backdoor

A backdoor is a piece of software that allows access to the computer
system bypassing the normal authentication procedures. Based on how they
work and spread, there are two groups of backdoors. The first group
works much like a Trojan, i.e., they are manually inserted into another
piece of software, executed via their host software and spread by their
host software being installed. The second group works more like a worm
in that they get executed as part of the boot process and are usually
spread by worms carrying them as their payload. The term Ratware has
arisen to describe backdoor malware that turns computers into zombies
for sending spam. The installed software can also be used for
anonymizing traffic, brute force cracking of passwords and encryptions,
and distributed denial of service attacks (DDOS).

### Spyware

![](media/image24.png){width="3.6430555555555557in"
height="2.428472222222222in"}Spyware is a piece of software that
collects and sends information (such as browsing patterns in the more
benign cases or credit card numbers in more malicious cases) about users
or, more precisely, the results of their computer activity, typically
without explicit notification. They usually work and spread like Trojan
horses. The category of spyware is sometimes taken to include adware of
the less-forthcoming sort.

### Exploit

An exploit is a piece of software that attacks a particular security
vulnerability. Exploits are not necessarily malicious in intent --- they
are often devised by security researchers as a way of demonstrating that
a vulnerability exists. However, they are a common component of
malicious programs such as network worms.

### Rootkit

A rootkit is software inserted onto a computer system after an attacker
has gained control of the system. Rootkits often include functions to
hide the traces of the attack, as by deleting log entries or cloaking
the attacker\'s processes. Rootkits may also include backdoors, allowing
the attacker to easily regain access later; or exploit software to
attack other systems. Because they often hook into the operating system
at the kernel level to hide their presence rootkits can be very hard to
detect. The consensus of computer security experts is that if your
system has been compromised by a rootkit you should wipe your hard
drives and reinstall the operating system since you can never know if
you have successfully removed all traces of the rootkit.

### Key Logger

A keylogger is software that copies a computer user\'s keystrokes to a
file, which it may send to a hacker at a later time. Often the keylogger
will only \"awaken\" when a computer user connects to a secure website,
such as a bank. It then logs the keystrokes, which may include account
numbers, PIN\'s and passwords, *before* they are encrypted by the secure
website.

### Dialers

A dialer is a program that either replaces the phone number in a
modem\'s dial-up connection with a long-distance number, often out of
the country, in order to run up phone charges on pay-per-dial numbers,
or dials out at night to send keylogger or other information to a
hacker.

### URL injection

![](media/image25.png){width="3.6430555555555557in"
height="2.428472222222222in"}This software modifies the browser\'s
behavior with respect to some- or all domains. It modifies the url
submitted to the server to profit from a given affiliate scheme by the
content provider of the given domain. This is often transparent to the
user. The author profits at the expense of the user \-- often
surreptitiously. The Mozilla Firefox BetterSearch extension is one such
example as its affiliate \"feature\" is often unknown to the user.
Moreover the user has no option to disable that aspect.

## Overuse of the term \"virus\"

Because viruses were historically the first to appear, the term
\"virus\" is often applied, especially in the popular media, to all
sorts of malware. Modern anti-viral software strengthen this broader
sense of the term as their operation is never limited to viruses.

Malware should not be confused with defective software, that is,
software which is intended for a legitimate **purpose** but has errors
or bugs.