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Chap 1: Overview

Chap 1: Overview. Concepts of CIA: confidentiality, integrity, and availability Confidentiality: concealment of information The need arises from sensitive fields (military, industry)

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Chap 1: Overview

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  1. Chap 1: Overview • Concepts of CIA: confidentiality, integrity, and availability • Confidentiality: concealment of information • The need arises from sensitive fields (military, industry) • Examples: encryption (protect the key), access control, existence of the data, resource hiding (configuration, google 1.7 – 2.4 M servers.) • Integrity: prevent unauthorized or improper changes, is directly related to trustworthiness of data and sources • Include data integrity and origin integrity (has impact on trust), therefore, related to credibility • Prevention: • prevent unauthorized changes • changes in unauthorized ways • Detection • Report integrity violation (confine dirty data??)

  2. Chap 1: Overview • Concepts of CIA: confidentiality, integrity, and availability (continued) • Availability: ability to use the data or resources • Example of highway • DoS or DDoS attacks (SMS for cell phone) • Very difficult to detect • Is it attack or we are unlucky today • Attacker will mess with the security methods as well (packet tracing)

  3. Threats: • A potential violation of security (not necessarily occur at this moment). • The actions that cause such violations are called attacks. • 4 classes of threats: • Disclosure: unauthorized access to data • Deception: acceptance of false data • Disruption: interruption or prevention of correct operation • Usurpation: unauthorized control of the system

  4. Examples of threats: • Snooping: unauthorized interception, is a kind of disclosure (eavesdrop on wireless). Countered by confidentiality or other information hiding methods. • Modification: unauthorized change of data, may lead to deception, disruption, and usurpation. Countered by integrity. • Spoofing: impersonation, may lead to deception and usurpation. Countered by integrity. • Difference b/w impersonation and delegation • Denial of receipt or origin: is a kind of deception • Interesting questions: simultaneous contract signing

  5. Policy and mechanism • Policy is a statement of what is and what is not allowed. • Can be presented formally (in mathematical way) • Can be described in plain English • When two communicating parties have different policies, they may need to compromise (example b/w univ. and industry) • Mechanism is a method to enforce a policy. • May impact the system performance • Prevention: to fail an attack • Detection • Recovery: fix not only data, but also vulnerabilities • Tolerance

  6. Assumptions: • Security rests on assumptions of the required security and application environments • Assumptions of a security policy • A policy can correctly and unambiguously partitions system states into secure and insecure • A security mechanism will prevent a system from entering a insecure state • Define a security mechanism as secure, precise, or broad (the example of highway) • In real life, security mechanisms are usually broad (Why?)

  7. Assurance: • The level of trust that we put on a system is based on its specification, design, and implementation • Specification: desired function of the system • Design: translate specifications into components that will implement them. Need to determine whether the specifications are satisfied • Implementation: create a system that should satisfy the specification and design • Verification: complexity, input, assumptions • Testing: what to test, how to test

  8. Operational issues: • An isolated PC will not be attacked through network, but it cannot access network either • We must balance the benefit of protection against the cost of designing, implementation, and usage of a system • Cost-benefit analysis: • Protect data or regenerated data? Which is cheaper? • There are after-impacts as well. (view of company?)

  9. Operational issues (continued): • Risk analysis: • We must understand the kinds and levels of threats, and their likelihood to happen to determine the levels of protection • Risk is a function of environment • Risk changes with time • Low probability attacks still exist • You must act on the analysis results

  10. Operational issues (continued): • Laws and customs • The selection of policy and mechanisms must consider legal issues: Example of encryption export and email monitor • A legal security mechanism is not necessarily acceptable: submit your DNA so we have bio-based authentication • A good technology is not necessarily being widely adopted: security is beyond technology

  11. Human issues: • Get the security tools from right hands, and put them into right hands • Organizational issues: • Security does not directly generate profit, but reduce potential losses • It often reduces performance • Power and responsibility must be properly linked • Shortage in people and resources

  12. Human issues (continued): • People issues: • People is heart of any security system • Attacks from outsider and insiders • Under trained workers and administrators • Social engineering based break-ins (in a bar at SV you can learn a lot) • The problem of misconfiguration (Example of SigComm)

  13. Putting them together: • Feedback and maintenance is important • Pay close attention to figure 1-1 on page 20

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