Computer Security: Concepts and Objectives

• Computer Security: Protection afforded to an automated information system.

Key Objectives

• Preserving integrity
• Availability
• Confidentiality of information system resources (hardware, software, firmware, information/data, and telecommunications)

Key Security Concepts

Data confidentiality

• Assures that private or confidential information is not available or disclosed to unauthorized individuals

Privacy

• Assures that individuals control or influence what information related to them may be collected and stored, and by whom and to whom that information may be disclosed.

Data integrity

• Assures that information and programs are changed only in a specified and authorized manner.

System integrity

• Assures that a system performs its intended function correctly.

Availability

• Assures that systems work promptly and service is not denied to authorized users.
• Confidentiality, integrity, and availability form the CIA triad.
• Authenticity and accountability are additional concepts needed to present a complete security picture.

Authenticity

• Being able to be verified and trusted.
• Confidence in the validity of a transmission or a message generator.
• Verifying that users are who they say they are and that each input arriving at the system come from a trusted source.

Authorization

• The process of giving someone permission or the right to do or have something.

Accountability

• Generates the requirement for action of an entity to be traced uniquely to that entity.
• Supports nonrepudiation, meaning a user cannot deny performing a transaction.
• Traces security breaches to a responsible party.
• Keeps records of activities to permit later forensic analysis to trace security breaches or to aid in transaction disputes.

Levels of Impact (Breach Impact)

• Low: limited effect expected
• Moderate: serious effect expected.
• High: severe or catastrophic effect expected.

Computer Security Challenges

• Attackers only need to find one weakness, developers need to find all.
• Security benefits are often unseen until a failure occurs.
• Requires regular, constant monitoring.
• Often incorporated after the design is complete.
• Sometimes seen as an obstacle to efficient, user-friendly operation.

Security Terminology

Vulnerability

• Weakness in a system's design, implementation, or operation and management.

Security Policy

• A set of rules and practices specifying how a system provides security services to protect sensitive and critical system resources.

Threat

• An event that could cause a security breach and harm the system.
• Capable of exploiting vulnerabilities.
• Represents potential security harm to a system
• Examples include removable media, brute force attacks, unauthorized use of system privileges, and loss/theft of confidential devices.

Countermeasure

• An action, device, procedure, or technique that reduces a threat, vulnerability, or an attack.

Risk

• The probability that a threat will exploit a vulnerability with a harmful result.

Asset

• System resource that is to be protected (hardware, software, data, communication lines, etc.)

Security Concepts

• Owners impose countermeasures to minimize risk to assets threatened by threat agents, resulting in threats. Vulnerabilities
• Corrupted: Does the wrong thing or gives wrong answers, leading to loss of integrity.
• Leaky: Unauthorized access to information, leading to loss of confidentiality.
• Unavailable: System is too slow or impractical, leading to loss of availability.

Attacks

• Threats carried out.

Insider attack:

• Initiated by an entity inside the organization.

Outsider attack:

• Initiated from outside the organization.

Attacks can be:

Passive:

• Attempts to learn or use information without affecting system resources.
• Eavesdropping or monitoring transmissions aims for gaining information transmitted. Includes:
• Release of message contents.
• Traffic analysis.

Active:

• Attempts to alter system resources or affect their operation, involving data stream modification, or creating a false stream.
• Categories include replay, masquerade, message modification, and denial of service.

Countermeasures

• Used to deal with security attacks including:
• Prevent
• Detect
• Recover
• Can introduce new vulnerabilities, goal is to minimize the residual risk for the assets

Computer Security Strategy

• A plan involving best practices to protect an organization from internal and external threats.
• A plan of action to maximize security and resiliency. Components:

Security Policy:

• Formal statement of rules and practices.

Security Implementation:

• Prevention
• Detection
• Response
• Recovery

Assurance:

• Confidence in the effectiveness of security measures.

Evaluation:

• Examining a computer product or system per specific security criteria.

Explore computer security, focusing on protecting automated information systems. Understand key objectives like preserving integrity, availability, and confidentiality. Learn about data confidentiality, privacy, data integrity, system integrity, and the CIA triad.