operating-systems security

Definition

Security

Security encompasses strategies, precautions, and tools ensuring confidentiality, integrity, and availability of information.

CIA Triad

Confidentiality

Data is only accessible to authorised users.

Integrity

Data remains accurate and unmodified except by authorised users.

Availability

Data and services are accessible when needed.

Security Concerns

Authenticity

Verifying that an identity (user or process) is who it claims to be.

Accountability

All actions traceable to a specific actor (via logging/auditing).

Threat Types

Passive Threats

Monitoring or eavesdropping without detection. Violates confidentiality.

Active Threats

Manipulation of data or system states. Violates integrity and availability:

  • Interruption: Service unavailable (destruction, overload)
  • Interception: Unauthorised data access
  • Modification/Fabrication: Unauthorised change or creation
  • Theft of Service: Unauthorised resource use
GoalThreat
ConfidentialityExposure / Interception
IntegrityModification / Fabrication
AvailabilityDenial of Service (DoS)