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Network & Computer Security

Prof. Giovambattista Ianni - 2013. Network & Computer Security. 10 ECTS (5 Theory + 5 Lab.) Suggested material : W. Stallings , Cryptography and Network Security W. Stallings, Computer Security: Principles and Practice Online material Required skills:

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Network & Computer Security

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  1. Prof. Giovambattista Ianni - 2013 Network & ComputerSecurity

  2. 10 ECTS (5 Theory + 5 Lab.) • Suggestedmaterial: • W. Stallings, Cryptography and Network Security • W. Stallings, Computer Security: Principles and Practice • Online material • Required skills: • Operating Systems, Computer Networks, Databases, Web Information Systems InformaTION

  3. Talk on a selectedtopic The talk must include a live demo Oralexam ExaM procedure

  4. Part 1: Cryptography on the field • Hashing, Asymmetric and Symmetric Cryptography, PKI • Part 2: a travel into the security of the TCP/IP stack • Part 3: Host security. Programming security. • Laboratory: Linux, simulations with Netkit • Ongoing projects Course PrograM

  5. FOOD of the day • Pancake  Cake made in the Pan • Poorlyknown in Italyas «Frittelle»

  6. Who/what sits in the playfield: • Computers • Networks • Humans (stupid and not stupid ones) The players: • Attackers: black and white hackers • Defenders: sysadmins, programmers, users DICTIONARY - I

  7. consider 3 aspects of information security: • security attack • security mechanism • security service • note terms • threat – a potential for violation of security • attack – an assault on system security, a deliberate attempt to evade security services DICTIONARY - II

  8. The possiblemoves (Attack types): • Attacks to integrity • Data counterfeiting, identitytheft • Attacks to confidentiality • Weak and strong information theft • Attacks to the quality of service • Denial of service • Authenticity, accountability DICTIONARY - III

  9. Key Security Concepts

  10. The art of war teaches us to rely not on the likelihood of the enemy's not coming, but on our own readiness to receive him; not on the chance of his not attacking, but rather on the fact that we have made our position unassailable. —The Art of War, Sun Tzu

  11. Estimated Money loss per year due to security breaches in your company = L • Estimated Money loss per year due to uncontrolledsystemadministrator/programmersparanoidism = D L > D PARANOID vs unsecured

  12. Passive Attacks

  13. Active Attacks

  14. enhance security of data processing systems and information transfers of an organization • intended to counter security attacks • using one or more security mechanisms • often replicates functions normally associated with physical documents • which, for example, have signatures, dates; need protection from disclosure, tampering, or destruction; be notarized or witnessed; be recorded or licensed Security Service

  15. Authentication - assurance that communicating entity is the one claimed • have both peer-entity & data origin authentication • Access Control - prevention of the unauthorized use of a resource • Data Confidentiality –protection of data from unauthorized disclosure • Data Integrity - assurance that data received is as sent by an authorized entity • Non-Repudiation - protection against denial by one of the parties in a communication • Availability – resource accessible/usable Security Services (X.800)

  16. feature designed to detect, prevent, or recover from a security attack • no single mechanism that will support all services required • however one particular element underlies many of the security mechanisms in use: • cryptographic techniques • hence our focus on this topic Security Mechanism

  17. specific security mechanisms: • encipherment, digital signatures, access controls, data integrity, authentication exchange, traffic padding, routing control, notarization • pervasive security mechanisms: • trusted functionality, security labels, event detection, security audit trails, security recovery Security Mechanisms (X.800)

  18. Model for Network Security

  19. Model for Network Access Security

  20. Fifth Edition by William Stallings Lecture slides by Lawrie Brown Cryptography and Network SecurityChapter 1

  21. Cryptographic algorithms • symmetric ciphers • asymmetric encryption • hash functions • Mutual Trust • Network Security • Computer Security Roadmap

  22. National Institute of Standards & Technology (NIST) • Internet Society (ISOC) • International Telecommunication Union Telecommunication Standardization Sector (ITU-T) • International Organization for Standardization (ISO) Standards Organizations

  23. The combination of space, time, and strength that must be considered as the basic elements of this theory of defense makes this a fairly complicated matter. Consequently, it is not easy to find a fixed point of departure.. — On War, Carl Von Clausewitz Chapter 1 – Introduction

  24. the protection afforded to an automated information system in order to attain the applicable objectives of preserving the integrity, availability and confidentiality of information system resources (includes hardware, software, firmware, information/data, and telecommunications) Computer Security

  25. can define 3 levels of impact from a security breach • Low • Moderate • High Levels of Impact

  26. confidentiality – student grades integrity – patient information availability – authentication service Examples of Security Requirements

  27. Computer Security Challenges not simple must consider potential attacks procedures used counter-intuitive involve algorithms and secret info must decide where to deploy mechanisms battle of wits between attacker / admin not perceived on benefit until fails requires regular monitoring too often an after-thought regarded as impediment to using system

  28. ITU-T X.800 “Security Architecture for OSI” defines a systematic way of defining and providing security requirements for us it provides a useful, if abstract, overview of concepts we will study OSI Security Architecture

  29. X.800: “a service provided by a protocol layer of communicating open systems, which ensures adequate security of the systems or of data transfers” • RFC 2828: “a processing or communication service provided by a system to give a specific kind of protection to system resources” Security Services

  30. using this model requires us to: • design a suitable algorithm for the security transformation • generate the secret information (keys) used by the algorithm • develop methods to distribute and share the secret information • specify a protocol enabling the principals to use the transformation and secret information for a security service Model for Network Security

  31. using this model requires us to: • select appropriate gatekeeper functions to identify users • implement security controls to ensure only authorised users access designated information or resources Model for Network Access Security

  32. topic roadmap & standards organizations • security concepts: • confidentiality, integrity, availability • X.800 security architecture • security attacks, services, mechanisms • models for network (access) security Summary

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