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Explore fundamental components of computer security, types of threats, policies, mechanisms, trust roles, and operational and human issues in ECS 235. Understand the importance of confidentiality, integrity, availability, and assurance in maintaining security. Learn about security goals, trust assumptions, types of mechanisms, and operational considerations. Discover design principles such as least privilege, fail-safe defaults, and separation of privilege for robust security practices in ECS 235.
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Chapter 1: Introduction • Components of computer security • Threats • Policies and mechanisms • The role of trust • Assurance • Operational Issues • Human Issues ECS 235
Basic Components • Confidentiality • Keeping data and resources hidden • Integrity • Data integrity (integrity) • Origin integrity (authentication) • Availability • Enabling access to data and resources ECS 235
Classes of Threats • Disclosure • Snooping • Deception • Modification, spoofing, repudiation of origin, denial of receipt • Disruption • Modification • Usurpation • Modification, spoofing, delay, denial of service ECS 235
Policies and Mechanisms • Policy says what is, and is not, allowed • This defines “security” for the site/system/etc. • Mechanisms enforce policies • Composition of policies • If policies conflict, discrepancies may create security vulnerabilities ECS 235
Goals of Security • Prevention • Prevent attackers from violating security policy • Detection • Detect attackers’ violation of security policy • Recovery • Stop attack, assess and repair damage • Continue to function correctly even if attack succeeds ECS 235
Trust and Assumptions • Underlie all aspects of security • Policies • Unambiguously partition system states • Correctly capture security requirements • Mechanisms • Assumed to enforce policy • Support mechanisms work correctly ECS 235
Types of Mechanisms secure broad precise set of reachable states set of secure states ECS 235
Assurance • Specification • Requirements analysis • Statement of desired functionality • Design • How system will meet specification • Implementation • Programs/systems that carry out design ECS 235
Operational Issues • Cost-Benefit Analysis • Is it cheaper to prevent or recover? • Risk Analysis • Should we protect something? • How much should we protect this thing? • Laws and Customs • Are desired security measures illegal? • Will people do them? ECS 235
Human Issues • Organizational Problems • Power and responsibility • Financial benefits • People problems • Outsiders and insiders • Social engineering ECS 235
Tying Together Threats Policy Specification Design Implementation Operation ECS 235
Chapter 13: Design Principles • Overview • Principles • Least Privilege • Fail-Safe Defaults • Economy of Mechanism • Complete Mediation • Open Design • Separation of Privilege • Least Common Mechanism • Psychological Acceptability ECS 235
Overview • Simplicity • Less to go wrong • Fewer possible inconsistencies • Easy to understand • Restriction • Minimize access • Inhibit communication ECS 235
Least Privilege • A subject should be given only those privileges necessary to complete its task • Function, not identity, controls • Rights added as needed, discarded after use • Minimal protection domain ECS 235
Fail-Safe Defaults • Default action is to deny access • If action fails, system as secure as when action began ECS 235
