About Internet, Database, Cyber Crime for study purposes and for knowledge .

1. Lecture 12
Internet, Database,
Cyber Crime
Lecturer: Sumaira Hussain
S.M.I University

2. Internet
A collection of interconnected networks –
looks like a single, unified network

3. Internet
 Enables users located at far-way locations to easily
share information with others located all over the
world
 Enables users to easily and inexpensively
communicate with others located all over the world
 Enables the users to operate and run programs on
computers located all over the world
 The Internet is unlike any previous human
invention. It is a world-wide resource, accessible to
all of the humankind.

4. Key Characteristics
 Geographic Distribution
Global - reaches around the world
 Robust Architecture
Adapts to damage and error
 Speed
Data can travels at near ‘c’ on
copper, fiber, airwaves

5. Key Characteristics
 Universal Access
Same functionality to everyone
 Growth Rate
The fastest growing technology ever
 Freedom of Speech
Promotes freedom of speech
 The Digital Advantage
Is digital: can correct errors

6. Internet Networking Protocol
Communications on the Internet is controlled by a set of two
protocols: TCP and IP
TCP/IP Transmission Control Protocol/Internet Protocol
TCP breaks down the message to be sent over the Internet into
packets
IP routes these packets through the Internet to get them to their
destination
When the packets reach the destination computer, TCP
reassembles them into the original message

7. IP Address
 A unique identifier for a computer on a
TCP/IP network
 Format: four 8-bit numbers separated
by periods. Each 8-bit number can be
0 to 255
 Example: www.smiu.edu.pk
(192.254.232.36)

8. Domain Name
 A domain name is a meaningful, easy-
to-remember ‘label’ for an IP address
 Example: www.smiu.edu.pk
(192.254.232.36)

9. Domain Name System
 DNS is the way that Internet domain
names are located & translated into IP
addresses

10. Internet Services
 FTP
 Telnet
 Web
 eMail
 Instant messaging
 VoIP

11. File Transfer Protocol (FTP)
Used to transfer files between computers
on a TCP/IP network (e.g. Internet)
Simple commands allow the user to:
 List, change, create folders on a remote
computer
 Upload and download files
 Typical use: Transferring Web content from
the developer’s PC to the Web server

12. Telnet Protocol
Using Telnet, a user can remotely log on to a
computer (connected to the user’s through a
TCP/IP network, e.g. Internet) & have
control over it like a local user, including
control over running various programs
 In contrast, FTP allows file operations only
 Typical use: Configuring and testing of a
remote Web server

13. Web
 The greatest, shared resource of
information created by humankind
 A user may access any item on the
Web through a URL, e.g.
http://smiu.edu.pk/under-graduate-programs.php
Protocol
Identifier
Server Address Directory & File Name

14. E-Mail
 Computer-to-computer messaging
 Components:
eMail Clients
 Programs used for writing, sending, receiving, and
displaying eMail messages Example: YahooMail
SMTP: Simple Mail Transfer Protocol
 A protocol used to send and receive eMail
messages over a TCP/IP network
POP3: Post Office Protocol
 A protocol used for receiving eMail messages
 A POP3 server maintains text files (one file per user
account) containing all messages received by a
user

15. Instant Messaging
 The IM services available on the
Internet (e.g. ICQ, AIM, MSN
Messenger, Yahoo! Messenger) allow
us to maintain a list of people
(contacts) that we interact with
regularly
 We can send an instant messages to
any of the contacts in our list as long
as that contact is online

16. Voice over IP (VoIP)
 Voice delivered from one device to
another using the Internet Protocol
 Voice is first converted into a digital
form, is broken down into packets, and
then transmitted over a TCP/IP
network (e.g. Internet)

17. Data & Information
 Data refers to raw facts & figures
 Information is an organized form of
data

18. Data Integrity
 Integrity refers to maintaining the correctness and
consistency of the data
– Correctness: Free from errors
– Consistency: No conflict among related data items
 Integrity can be compromised in many ways:
– Typing errors
– Transmission errors
– Hardware malfunctions
– Program bugs
– Viruses
– Fire, flood, etc.

19. Database
 A collection of data organized in such
a fashion that the computer can
quickly search for a desired data item

20. Database Management System
 DBMS takes care of the storage, retrieval, and
management of large data sets on a database
 It provides SW tools needed to organize &
manipulate that data in a flexible manner
 It includes facilities for:
– Adding, deleting, and modifying data
– Making queries about the stored data
– Producing reports summarizing the required contents

21. Database Characteristics
 Similar items of data form a column
 Fields placed in a particular row are strongly
interrelated
 One can sort the table w.r.t. any column
 That makes searching straight forward e.g., for all
the books written by a certain author
 Similarly, searching for the 10 cheapest/most
expensive books can be easily accomplished
through a sort
 Effort required for adding a new column to the table
is much smaller

22. Example
Title Author Publisher Price InStock
The Terrible
Twins
Bhola
Champion
BholiBooks 199 Y
Calculus &
Analytical
Geometry
Smith
Sahib
Good
Publishers
325 N
Accounting
Secrets
Zamin
Geoffry
Sung-e-
Kilometer
Publishers
29 Y

23. Example
Customer Title Shipment Type
Saad The Terrible
Twins
24-10-2014 Air
Asad Calculus &
Analytical
Geometry
23-03-2014 Surface
Ali Accounting
Secrets
12-06-2014 Air
They share a column, & are related through it
A program can match info from a field in one table with info in a
corresponding field of another table to generate a 3rd table that combines
requested data from both tables

24. Question
who has spent the most money on
the online bookstore

25. Answer
Customer Price
Saad 199
Asad 325
Ali 29

26. Relational Database
 Databases consisting of two or more related tables are
called relational databases
 A typical relational database may have anywhere from
10 to over a thousand tables
 Each column of those tables can contain only a single
type of data (contrast this with spreadsheet columns!)
 Table rows are called records; row elements are called
fields
 A relational database stores all its data inside tables,
and nowhere else
 All operations on data are done on those tables or those
that are generated by table operations

27. RDBMS
 Relational DBMS software
 Contains facilities for creating, populating,
modifying, and querying relational
databases
 Examples:
–Access – DB2
–FileMaker Pro – Objectivity/DB
–SQL Server – MySQL
–Oracle – Postgres

28. Terminologies
 Primary Key is a field that uniquely identifies each record
stored in a table
 Queries are used to view, change, and analyze data. They
can be used to:
– Combine data from different tables, efficiently
– Extract the exact data that is desired
 Forms can be used for entering, editing, or viewing data, one
record at a time
 Reports are an effective, user-friendly way of presenting data.
 Data normalization is the process of efficiently organizing
data in a database. There are two goals of the normalization
process:
– Eliminate redundant data
– Storing only related data in a table

29. Cyber Crime
07 February 2000
• Users trying to get on to the Web sites of Yahoo, couldn’t!
• Reason: Their servers were extremely busy!
• They were experiencing a huge number of hits
• The hit-rate was superior to the case when a grave incident (e.g. 9/11) occurs,
and
people are trying to get info about what has happened
• The only problem was that nothing of note had taken place!
What was going on?
• A coordinated, distributed DoS (Denial of Service) attack was taking place
• Traffic reached 1 GB/s; many times of normal!
• In the weeks leading to the attack, there was a noticeable rise in the number of
scans that Internet servers were receiving
• Many of these scans appeared to originate from IP addresses that traced back to
Korea, Indonesia, Taiwan, Australia

30. Three Phases of the DoS
1. Search for Drones
• The attackers set about acquiring the control over the computers to be used in the
attack …
• by scanning – using e.g. Sscan SW – a large numbers of computers attached to the
Internet
• Once a computer with a weak security scheme is identified, the attackers try a
break-in
• Once conquered, that computer – called a drone – will be used to scan others
2. Arming the Drones
• After several drones have been conquered, the DoS SW is loaded on to them
• Examples: Tribal Flood Network, Trinoo, TFN2K
• Like a time-bomb, that SW can be set to bring itself into action at a specified time
• Alternatively, it can wait for a commencement command from the attacker
3. The Actual Attack
• At the pre-specified time or on command, the SW implanted on all of the drones
wakes-up and starts sending a huge number of messages to the targeted servers
• Responding to those messages overburdens the targeted servers and they become
unable to perform their normal functions

31. DoS Attack: A Cyber Crime
 DoS is a crime, but of a new type - made possible by the
existence of the Internet
 A new type of policing and legal system is required to tackle
such crimes and their perpetrators
 Internet does not know any geographical boundaries,
therefore jurisdiction is a key issue when prosecuting the
cyber-criminal
Cyber crime can be used to …
 Damage a home computer
 Bring down a business
 Weaken the telecom, financial, or even defense-related
systems of a country

32. Viruses
 Self-replicating SW that eludes detection and is
designed to attach itself to other files
 Infects files on a computers through:
– Floppy disks, CD-ROMs, or other storage media
– The Internet or other networks
 Viruses cause tens of billions of dollars of damage each
year
 One such incident in 2001 – the LoveBug virus – had an
estimated cleanup/lost productivity cost of US$8.75
billion
 The first virus that spread world-wide was the Brain
virus, and was allegedly designed by someone in Lahore

33. Antivirus SW
 Designed for detecting viruses & inoculating
 Continuously monitors a computer for known
viruses and for other tell-tale signs like:
– Most – but, unfortunately not all – viruses increase
the size of the file they infect
– Hard disk reformatting commands
– Rewriting of the boot sector of a hard disk
 The moment it detects an infected file, it can
automatically inoculate it, or failing that, erase it