1. The document defines computer security as protecting computer systems and information from harm, theft, and unauthorized use through preventing and detecting unauthorized computer system access. 2. It discusses various types of computer security including information, application, computer, network, and cyber security and outlines common computer security threats like viruses, worms, phishing, rootkits, and key loggers. 3. The document also covers fundamental computer security objectives of confidentiality, integrity, and availability and related terminology like adversaries, attacks, vulnerabilities, and security policies.

1. SUBJECT NAME: INFORMATION SECURITY
CHAPTER NO.: 1
CHAPTER NAME: COMPUTER SECURITY FUNDAMENTALS
LECTURE NO: 1
COMPUTER SCIENCE

2. Computer Security Concepts

3. Definition
The Protection of computer system and information from harm, theft, and unauthorized
use.
The process of preventing and detecting unauthorized use of computer system.
Computer Security

4. NIST Definition
The protection afforded to an automated information system in order to attain the
applicable objectives of preserving the
• Integrity
• Availability
• Confidentiality
of information system resources (includes hardware, software, firmware,
information/data, and telecommunications).
Computer Security

5. Types
• Information Security – Securing information from access, modification, and
deletion
• Application Security – Securing application from SQL injection, DDOS, and data
breach
• Computer Security – Securing physical computer machine
• Network Security – Securing both software and hardware technologies of the
network
• Cyber Security – Protecting computer system which communicate over the
network
Computer Security

6. • Virus – a malicious program which is loaded into computer system without user’s
knowledge. It replicates itself and infects files and program on computer.
• Worms – a software program that can copy itself from one to another computer with
out human interaction. Potential risk is using p computer hard disk space.
• Phishing – attempts to steal sensitive financial or personal information through
fraudulent emails or instant messages.
• Rootkit – is a computer program designed to provide continuous privileged access to a
computer. After tacking control of privileged user, hacker executes files remotely and
change system configurations.
• Key Logger – tracks real time activities of a user.
Computer Security Threats

7. • Eavesdropping – observes traffic on your system and the work you are doing.
Examples: email, website, and file monitoring.
• Password Attack – finds password of your accounts.
• Dictionary attack
• Brute force
• Key logger
• Shoulder surfing
• Rainbow table
• SQL Injection – injects malicious i/p into SQL statement to get access to database files.
• Social Engineering – Social situation that encourages you to share your password.
Computer Security Threats

8. 1. Confidentiality: means data, objects, and resources are protected from unauthorized access.
• Data confidentiality – assures that private or confidential information is not made
available or disclosed to unauthorized person.
• Privacy – assures that individual control what information is related to them may be
collected, stored, by whom, and to whom information is disclosed.
2. Integrity: data protected from unauthorized modification or changes. Ensures data is reliable
and correct
• Data integrity – assures that data is changed only in a specified manner and authorized
way.
• System integrity – assures that the system performs intended function in an unimpaired
way, free from deliberate / inadvertent unauthorized manipulation of the system.
3. Availability: assures that system work properly and service is not denied to the authorized
users.
Three key objectives of Computer Security

9. Additional two of the most commonly mentioned objectives are
1. Authenticity – is a property of being genuine , variable, and trusted.
2. Accountability – is a process of mapping action to an identity.
CIA Triad

10. Three levels of impact on organizations or individuals
1. Low
2. Moderate
3. High
Impact of breach of security

11. Computer Security Terminology
Adversary (threat agent) – an entity that attacks or is a threat to a system may be a
individuals, systems, or programs. Example: Hacker, organized crime, nation state
Attack – an assault on a system security that drives from an intelligent threat.
Countermeasure – an action, device, procedure or technique that reduces a threat, a
vulnerability, an attack by eliminating or preventing it.
Risk – an expectation of loss expressed as the probability that a particular threat will
exploit a particular vulnerability with a particular harmful result.
Security Policy – a set of rules and practices that specifies / regulate how a system /
organization provides security services to protect system resources.
A Model for Computer Security

12. Computer Security Terminology
System Resource (Asset) – data contained in a information systems.
Threat – a potential for violation of security or is a possible danger that might exploit a
vulnerability.
Vulnerability – a flaw / weakness in a system design, implementation, operation and
maintenance that could be violated system security.
A Model for Computer Security

13. System Resource or Asset
1. Hardware
2. Software
3. Data
4. Communication facilities and
networks
A Model for Computer Security

14. Categories of vulnerabilities
1. Corrupted – does wrong thing
or gives wrong answers.
2. Leaky – information may be
disclosed.
3. Unavailable – system or
network becomes impossible or
impractical.
A Model for Computer Security

15. Types of Attacks
1. Active attack – an attempt to alter system resources or affect their resources.
2. Passive attack – an attempt to learn or make use of information from the system.
Attacks based on the origin of the attack
1. Inside attack – initiated by an entity inside security perimeter. Insider is
authorized to access system resources but use them in a way not approved.
2. Outside attack - initiated by an entity from outside security perimeter.
Example: Hacker, Terrorist, etc.
A Model for Computer Security