Upload
leonard-daniel
View
213
Download
0
Tags:
Embed Size (px)
Citation preview
IntroductionIntroduction
(Based on Lecture slides by J. H. Wang)(Based on Lecture slides by J. H. Wang)
The art of war teaches us to rely not on the The art of war teaches us to rely not on the likelihood of the enemy's not coming, but likelihood of the enemy's not coming, but on our own readiness to receive him; not on our own readiness to receive him; not on the chance of his not attacking, but on the chance of his not attacking, but rather on the fact that we have made our rather on the fact that we have made our position unassailable. position unassailable. ——The Art of War, The Art of War, Sun TzuSun Tzu
The combination of space, time, and The combination of space, time, and strength that must be considered as the strength that must be considered as the basic elements of this theory of defense basic elements of this theory of defense makes this a fairly complicated matter. makes this a fairly complicated matter. Consequently, it is not easy to find a fixed Consequently, it is not easy to find a fixed point of departurepoint of departure. . — — On War, Carl Von ClausewitzOn War, Carl Von Clausewitz
Computer SecurityComputer Security
The protection afforded to an automated The protection afforded to an automated information system in order to attain the information system in order to attain the applicable objectives of preserving the applicable objectives of preserving the integrityintegrity, , availabilityavailability and and confidentialityconfidentiality of of information system resources (includes information system resources (includes hardware, software, firmware, hardware, software, firmware, information/data, and telecommunications)information/data, and telecommunications)[NIST 1995][NIST 1995]
Three Key Objectives
Confidentiality Data confidentiality Privacy
Integrity Data integrity System integrity
Availability Additional concepts
Authenticity Accountability
Levels of ImpactLevels of Impact
3 levels of impact from a security breach3 levels of impact from a security breach LowLow ModerateModerate HighHigh
Examples of Security Examples of Security RequirementsRequirements
confidentiality – student gradesconfidentiality – student grades integrity – patient informationintegrity – patient information availability – authentication serviceavailability – authentication service
Computer Security ChallengesComputer Security Challenges
1.1. not simplenot simple2.2. must consider potential attacksmust consider potential attacks3.3. procedures used counter-intuitiveprocedures used counter-intuitive4.4. involve algorithms and secret infoinvolve algorithms and secret info5.5. must decide where to deploy mechanismsmust decide where to deploy mechanisms6.6. battle of wits between attacker / adminbattle of wits between attacker / admin7.7. not perceived on benefit until failsnot perceived on benefit until fails8.8. requires regular monitoringrequires regular monitoring9.9. too often an after-thoughttoo often an after-thought10.10. regarded as impediment to using systemregarded as impediment to using system
Aspects of SecurityAspects of Security
3 aspects of information security:3 aspects of information security: security attacksecurity attack security mechanism: detect, prevent, security mechanism: detect, prevent,
recoverrecover security servicesecurity service
termsterms threat threat –– a a potential for violation of securitypotential for violation of security attack attack –– an an assault on system security, a assault on system security, a
deliberate attempt to evade security servicesdeliberate attempt to evade security services
Passive attacks do not affect system resources Eavesdropping, monitoring
Two types of passive attacks Release of message contents Traffic analysis
Passive attacks are very difficult to detect Message transmission apparently normal
• No alteration of the data Emphasis on prevention rather than detection
• By means of encryption
Active attacks try to alter system resources or affect their operation
Modification of data, or creation of false data Four categories
Masquerade Replay Modification of messages Denial of service: preventing normal use
• A specific target or entire network Difficult to prevent
The goal is to detect and recover
Security ServiceSecurity Service
enhance security of data processing systems enhance security of data processing systems and information transfers of an organizationand information transfers of an organization
intended to counter security attacksintended to counter security attacks using one or more security mechanisms using one or more security mechanisms often replicates functions normally associated often replicates functions normally associated
with physical documentswith physical documents• which, for example, have signatures, dates; need which, for example, have signatures, dates; need
protection from disclosure, tampering, or protection from disclosure, tampering, or destruction; be notarized or witnessed; be destruction; be notarized or witnessed; be recorded or licensedrecorded or licensed
Security MechanismSecurity Mechanism
feature designed to detect, prevent, or feature designed to detect, prevent, or recover from a security attackrecover from a security attack
no single mechanism that will support all no single mechanism that will support all services requiredservices required
however however one particular element underlies one particular element underlies many of the security mechanisms in use:many of the security mechanisms in use: cryptographic techniquescryptographic techniques
hence our focus on this topichence our focus on this topic