This document discusses information security and privacy. It begins by defining computer viruses and how they work, reproducing and attaching to other programs. It then discusses popular types of viruses like file infectors, boot sector viruses, Trojan horses, and worms. The document outlines how viruses can damage systems and be spread, as well as common symptoms. It recommends prevention methods like antivirus software and firewalls. The document concludes by covering data security issues in the US, categories of security breaches, and the Privacy Act of 1974.

1. Information Security and Privacy
Presented by:-
Joy Chakraborty,
Roll: 11BM91S01,
Ph.D Scholar, 2011, VGSOM, IIT-Kharagpur
1

2. What is a Computer Virus?
• Any program that has the ability to reproduce and attach itself to other
programs is referred to as a computer virus.
• A virus can be designed to do various kinds of damage. It can perform a
variety of functions ranging from annoying (e.g., popping up messages as a
joke) to dangerous (e.g., deleting files or destroying your hard disk).
• To qualify as a virus, a program must be able to replicate (make copies of)
itself. This can mean copying itself to different places on the same
computer or looking for ways to reach other computers, such as by
infecting disks or traveling across networks.
• Computer viruses, unlike biological viruses, don’t spring up out of
nowhere—they’re created by people.
2

3. How Computer viruses work?
3

4. Few Popular Types of Viruses
• File Infector Viruses - The most “traditional” form of computer virus is the file infector virus,
which hides within the code of another program. Before the advent of the Internet, file infector
viruses accounted for probably 85% of all virus infections.
• Boot Sector Viruses - Boot sector viruses reside in the part of the disk that is read into memory
and executed when your computer first boots up. Once loaded, the virus can then infect any other
disk used by the computer; a disk-based boot sector virus can also infect a PC’s hard disk.
• Trojan Horses - Trojan horses are becoming more common, primarily through the spread of
Internet-based e-mail. These e-mail Trojans spread as innocent-looking attachments to e-mail
messages; when you click to open the attachment, you launch the virus.
• Chat and Instant Messaging Viruses - Most chat and IM programs let you send files across to
other users; and many users are also accustomed to accepting any files sent to them when they’re
chatting leading to transfer of viruses.
• E-mail viruses – E-mail viruses can be transmitted via email messages sent across private networks
or the Internet. According to Kaspersky Lab, the research arm of the company that produces
Kaspersky Anti-Virus software, e-mail viruses accounted for 90% of all virus attacks in 2001.
• Worms – A worm is a program whose purpose is to duplicate itself. Worms replicate themselves
very quickly; a network infected with a worm can be brought to its knees within a matter of hours
4

5. Life-cycle of a computer virus
5

6. What can a virus do?
• Copy themselves to other programs or areas of a disk.
• Replicate as rapidly and frequently as possible, filling up the infected
system’s disks and memory, rendering the system useless.
• Display information on the screen.
• Modify, corrupt, or destroy selected files.
• Erase the contents of entire disks.
• Lie dormant for a specified time or until a given condition is met, and then
becomes active.
• Open a “back door” to the infected system that allows someone else to
access and even take control of the system through a network or Internet
connection.
6

7. How one can pick up a virus?
• Receiving an infected file attached to an e-mail message, or a virus hidden
within the message itself.
• Viruses can even be spread through online chat rooms and instant messenger
programs.
• Downloading an infected file to your computer across a network, an online
service, or the Internet.
• Receiving an infected disk (a diskette, a CD created by someone with a CD-R
drive, a high-capacity floppy disk and so on) from another user.
• Copying to a disk a document file that is infected. An infected document might
be copied from another disk or received as an attachment to an e-mail
message.
7

8. Common virus infection symptoms
• Programs quit working or freeze up.
• Documents become inaccessible.
• Computer freezes up or won’t start properly.
• The CAPS LOCK key quits working—or works intermittently.
• Files increase in size.
• Frequent error messages appear onscreen.
• Strange messages or pictures appear onscreen.
• PC emits strange sounds.
• Friends and colleagues inform you that they’ve received strange e-mails
from you, that you don’t remember sending.
8

9. Prevention against Viruses
• Restrict your file downloading to known or secure sources
• Don’t open any e-mail attachments you weren’t expecting
• Use an up-to-date anti-virus program or service
• Create backup copies of all your important data
• Enable virus protection in all your applications
• Usage of Firewalls
9

10. Usage of Firewalls
• A firewall is a barrier to keep destructive forces away from your property, if one
has been using the Internet for any length of time, and especially if one works at a
larger company and browse the Web while he is at work
• Its job is similar to a physical firewall that keeps a fire from spreading from one
area to the next.
• Firewalls have helped protect computers in large companies for years. Now,
they're a critical component of home networks, as well.
10

11. Data Security issues in USA
• Computer security in USA has received attention in recent years by reports of
striking computer viruses and dramatic computer crimes that involve large sums of
money.
• The FBI uniform crime statistics do not separate computer from other sorts of
crime.
• Most of the incidents that are detected is not publicized because of shame, or
because of fear of damage to the organization’s or its management’s reputation, or
because of an agreement not to prosecute if the criminal goes away.
• US Dollar estimates of computer crime losses are only vague estimates and range
from $ 300 million to $ 500 billion per year. [Most of the expenses come from the
time and effort required to locate and remove viruses, restore systems, rebuild lost
or corrupted data, and ensure against future attacks.]
• Protection against computer crimes is made difficult due to the multiplicity of
targets and points of penetration.
11

12. Categories of Security Breaches
• Computer crime cases that involve software security breaches can be classified into 4
categories:
Interruption
Interception
Modification
Fabrication
• In an Interruption, an asset (hardware, software, or data) of the Computer-Based
Information System (CBIS) becomes unavailable, unusable or lost.
• An Interception occurs when an unauthorized party has gained access to an asset.
• Modification represents the security breach when an unauthorized party not only
accesses but tampers with an asset.
• Fabrication refers to introduction of counterfeit objects into a CBIS.
12

13. The Privacy Act of 1974
• The Privacy Act of 1974 (Dec.31, 1974) states :
No agency shall disclose any record which is contained in a system of records by any
means of communication to any person, or to another agency, except pursuant to a
written request by, or with the prior written consent of, the individual to whom the
record pertains.
• The Privacy Act mandates that each US Govt. agency have in place an administrative
and physical security system to prevent the unauthorized release of personal records.
• Federal agencies are subject to damages if an individual’s rights are violated.
• There are specific exceptions allowing the use of personal records:
1. For statistical purposes by the Census Bureau and the Bureau of Labor Statistics
2. For routine uses within a U.S. government agency
3. For law enforcement purposes
4. For congressional investigations
5. Other administrative purposes
13

14. References:-
• “Appendix C – Computer Viruses”, Introduction to Computers by Peter Norton,
sixth edition, McGraw Hill companies.
• “Social and Ethical Issues in Information Systems”, (Chapter-19), Principles of
Information Systems – A Managerial Approach, by Ralph M. Stair, Boyd and
Fraser Publishing company.
• Computer Security Institute (CSI), http://www.gocsi.com
• IBM Anti-virus Research, http://www.research.ibm.com/antivirus
• “How Firewalls work”, http://www.howstuffworks.com/firewall.htm
• Wikipedia sources
14

15. THANK YOU
15