This document discusses computer security and risks. It describes several types of computer crimes like software piracy, hacking, and computer sabotage using viruses, trojans, and worms. It explains how these crimes affect personal privacy and outlines some security measures to protect hardware, data, and replicate data through backups and RAID systems to reduce risks. Physical access restrictions and passwords, firewalls, encryption, and audit control software can help protect sensitive information on computers and networks.

1. Introduction to Computer Science
2007-2008
Computer Security
and Risks

2. 4626. Introd to Computer Science
Aims
• Describing several types of computer crime
• Describing the major security issues that
computer users have to face
• Describing how it affects to personal privacy
• Explaining the relationship between security
and computer reliability

3. 4626. Introd to Computer Science
Crime accomplished through computer tech.
• widely extended: easiness of computer
usage
• most of them committed by company
insiders
• high cost: foresight + repair
Current threats
• spoofing (or phishing): identity theft
Computer Crime

4. 4626. Introd to Computer Science
Software Piracy
• Illegal duplication of copyrighted software
• Reasons:
• price of software
• means to create copies
How many pirate programs do
you have?

5. 4626. Introd to Computer Science
Authorship rights
Industrial property
Intellectual Property
• Privileges granted over intangible goods with
financial value
• They are defined over
• copyright
• commercial secret
• patents
• trademarks
• Software is covered by copyright

6. 4626. Introd to Computer Science
Computer Sabotage
• Trojan horses
• Viruses
• Worms
Use of malware to spoil
hardware & software

7. 4626. Introd to Computer Science
Trojans
• hidden inside programs that perform
useful tasks
• logic bombs: programmed to ‘attack’ in
response to a particular event (e.g. time
bombs)
• solutions
• software from reliable sources
(avoids)
• anti-trojan (detects)
• firewall -output- (blocks)

8. 4626. Introd to Computer Science
Viruses
• as biological ones
• invade programs and use them to reproduce
themselves
• operative system specific
• solution:
• use carefully removable media (avoids)
• antivirus (detects and cleans)

9. 4626. Introd to Computer Science
Worms
• as viruses: use computers to
reproduce themselves
• autonomous spread through
computer networks
• solution:
• email from confident sources
(avoids)
• firewall -input- (blocks)
• security patches

10. 4626. Introd to Computer Science
Hacking
• Discovering and exploiting
computer system failures
• Reasons:
• curiosity
• intellectual challenge
• Cracking = criminal hacking

11. 4626. Introd to Computer Science
Reducing Risks
• to work properly
• to guarantee access
to information only
to granted users
• to guarantee
privacy
Information systems have to be protected...

12. 4626. Introd to Computer Science
Physical Access
Restrictions
• something you have (card)
• something you know (password)
• something you do (signature)
• something about you (scans)
Only authorised staff
have access to the equipment
Security checks based on…

13. How
can we protect
sensitive
information?

14. 1. protect hw

15. UPS
• uninterruptible
power supply
• protects data
during power
failures (minutes)
• give users time
to switch off
the system

16. 4626. Introd to Computer Science
Surge
protectors
• shield computers from power
spikes
• protect the computer from
physical damage

17. 2. protect data

18. 4626. Introd to Computer Science
Passwords
• which kind of password do you use?
• how frequently do you change your passwords?
• how many passwords do you use?
The most common tool,
but carefully chosen
Never use a word or your b-day!!

19. Firewalls
• guard against
unauthorised access
• blocks accessing ports for
input and output
• by hardware or software

20. 4626. Introd to Computer Science
Encryption
• keys to code messages
and documents
• symmetric:
common key
• asymmetric:
public / private keys

21. 4626. Introd to Computer Science
Audit Control SW
• Records computer
transactions
• Auditors can trace and
identify suspicious activities

22. 2. replicate

23. 4626. Introd to Computer Science
Backup Copies
• periodic copies of
important information
• for companies, it is
recommended that copies
be stored in a different
location

24. 4626. Introd to Computer Science
RAID
• Redundant Array of
Independent Disks
• multiple disks as
one logical unit
• mirroring: data
redundancy