CSE2500 System Security and Privacy

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CSE2500 System Security and Privacy
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Lecturers
Prof B Srinivasan Phone [phone] Room No
C4.47 srini_at_infotech.monash.edu.au
Ms Nandita BhattacharjeePhone 990 32185/990
53293Room No C4.05nandita_at_csse.monash.edu.au
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Organisation and Evaluation

• 12 weeks of lectures
• 2 hours of tutorials per week mainly problem
  solving, starting from week 2 to week 12.

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Weekly Lectures

• Lectures
• Wednesdays 7p.m. to 9p.m. in Caulfield K Block
  K3.21
• Alternative Lecture times?
• Fridays 12 noon to 2p.m. in Caulfield K block
  3.09
• Fridays 3p.m. to 5p.m. in Caulfield B block B2.13

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Tutorials

• Tutorials from week 2 to week 12
• Wednesdays 10a.m. in Caulfield/B471
• Wednesdays 4p.m. in Caulfield/B471
• Wednesdays 4p.m. in Caulfield/B476
• Thursdays 10a.m. in Caulfield/A212
• Thursdays 2p.m. in Caulfield/B224
• Thursdays 6p.m. in Caulfield/F206 or Wednesday
  5p.m in Caulfield/??
• Pl use Allocate for allocating tutorials. If
  you have any problems, please see us during the
  tutorial times next week.

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Assessment

• Four assessment components
• Two 30 min tests during the tutorial sessions
  in weeks 6 and 12, worth 15 each.
• Individual question solving during the tutorial
  session from weeks 7 to 11, worth 10
• Each student will be assigned a time slot and a
  problem and they have to make a presentation of
  the solution to the rest of the group.
• Examination 2 hours duration worth 60
• You need to get at least 50 to pass this unit.

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References

• Primary Reference book
• Security in Computing C P Pfleeger and S L
  Pfleeger, Third Edition, 2003, Prentice Hall
• Secondary Reference book
• Computer SecurityDieter Gollmann, 1999, John
  Wiley

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• Subject CSE2500
• Lecturers
• Prof. Bala Srinivasan
• Mrs. Nandita Bhattacharjee
• Prescribed Text
• Pfleeger
• Security in Computing 3e
• Available from the University Bookshop

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Where to look for the subject materials?

• http//www.csse.monash.edu.au/courseware/cse2500
• http//beast.csse.monash.edu.au/cse2500
• Please down load and print the lecture materials
  before coming to the class as NO further
  photocopies of notes will be distributed in the
  class.
• The lecture notes is complementary to the
  prescribed text.

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Security

• Why do you lock your house before you leave?
• How do you choose the kind of lock for your
  house?
• Any added devices (such as alarms, bull terrier,
  etc)
• What you do when you observe that things in the
  house are scattered around?

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What are you protecting?

• Brick and walls
• Money and jewellery
• Music CDs and tapes
• Etc .

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Threats to Computer and Communications systems

• Domain of information and network security
• Taxonomy of security attacks
• Aims or services of security
• Model of system/(inter)network security
• Methods of defense

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Security

• Human nature
• physical, financial, mental,, data and
  information security

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There are Problems

• Theft - of equipment
• Theft e.g. Copying of confidential material
• Modification - for gain e.g. Adding false names
  to payroll
• Modification - malicious e.g. Virus infections
• Access - easy for us and difficult for them
• .

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Fact sheet

• bank robbery through computers
• industrial espionage on corporate information
• loss of individual privacy (email, mobile
  phone/computer, fax, ...)
• information vandalism
• computer viruses
• (more can be found in comp.risks)

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What we mean by Security?

• Protection of assets - can take several forms
• Prevention
• Detection
• Reaction

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Reactions

• active research in security privacy(numerous
  conferences each year)
• new laws
• education
• collaborations between governments, industries
  academia
• employment of computer security specialists

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What that means for computer assets?

• What are the assets (for system security)?

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Information Security

• Shift from the physical security to the
  protection of data (on systems) and to thwart
  hackers (by means of automated software tools)
  called System and information security
  

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Network Security

• With the widespread use of distributed systems
  and the use of networks and communications
  require protection of data during transmission
  called network security

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Internetwork security

• The term Network Security may be misleading,
  because virtually all businesses, govt., and
  academic organisations interconnect their data
  processing equipment with a collection of
  interconnected networks probably we should call
  it as (inter)network security

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Aspects of System (and information) security

• Security attack any action that compromises the
  security of system and information.
• Security mechanism to detect, prevent, or
  recover from a security attack.
• Security service service that enhances and
  counters security attacks.

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Other terminology

• vulnerability
• a weakness in a computer system that might be
  exploited to cause loss or harm
• attack
• an action that exploits a vulnerability
• threat
• circumstances that have the potential to cause
  loss or harm
• control - a protective measure

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Security mechanisms

• No single mechanism that can provide the services
  mentioned in the previous slide. However one
  particular aspect that underlines most (if not
  all) of the security mechanism is the
  cryptographic techniques.
• Encryption or encryption-like transformation of
  information are the most common means of
  providing security.

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Why Security?

• Security is not simple as it might first appear.
• In developing a particular security measure one
  has to consider potential counter measures.
• Because of the counter measures, the problem
  itself becomes complex.
• Once you have designed the security measure, it
  is necessary to decide where to use them.
• Security mechanisms usually involve more than a
  particular algorithm or protocol.

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Security and Cost Analysis
cost
100
Security level
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Security Attacks - Taxonomy

• Interruption attack on availability
• Interception attack on confidentiality
• Modification attack on integrity
• Fabrication attack on authenticity

Property that is compromised
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Interruption

• Also known as denial of services.
• Information resources (hardware, software and
  data) are deliberately made unavailable, lost or
  unusable, usually through malicious destruction.
• e.g cutting a communication line, disabling a
  file management system, etc.

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Interception

• Also known as un-authorised access.
• Difficult to trace as no traces of intrusion
  might be left.
• e.g illegal eavesdropping or wiretapping or
  sniffing, illegal copying.

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Modification

• Also known as tampering a resource.
• Resources can be data, programs, hardware
  devices, etc.

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Fabrication

• Also known as counterfeiting (of objects such as
  data, programs, devices, etc).
• Allows to by pass the authenticity checks.
• e.g insertion of spurious messages in a
  network, adding a record to a file, counterfeit
  bank notes, fake cheques,
• impersonation/masquerading
• to gain access to data, services etc.

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Security Attacks - Taxonomy
Source and Destination - can be what is supposed
to be and what you get
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Attacks Passive types

• Passive (interception) eavesdropping on,
  monitoring of, transmissions.
• The goal is to obtain information that is being
  transmitted.
• Types here are release of message contents and
  traffic analysis.

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Attacks Active types

• Involve modification of the data stream or
  creation of a false stream and can be subdivided
  into masquerade, replay, modification of
  messages and denial of service.

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Attacks
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Security threats (to maintain) are

• Confidentiality
• Integrity
• Availability
• to give us secure data (and information)
• Authenticity

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Confidentiality

• Only accessible by authorised parties
• Not revealed
• More that just not reading
• Confidentiality is distinct from secrecy and
  privacy ( ?)

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Integrity

• Associated with loss and corruption
• Data Integrity as
• Computerised data same as external, source data
• Data not exposed to alteration or destruction
• No inappropriate modification

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Availability

• The property of being accessible and useable
  (without delay) upon demand by an authorised
  entity
• We want there to be
• no denial of service

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Other issues

• Accountability
• Reliability
• Safety
• Dependability

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Security is defined as

• Computer security deals with the prevention and
  detection of unauthorised actions by users of a
  computer system
• Security deals with the ready availability of
  valuable assets by authorised agents, and the
  denial of that access to all others

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The security dilemma

• security deals with the ready availability of
  valuable assets by authorised agents, and the
  denial of that access to all others.
• Security-unaware users have specific security
  requirements but (usually) no security
  expertise. But

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The security dilemma

• The costs of additional resources to implement
  security mechanisms can be quantified.
• Security mechanisms interfere with users, and can
  lead to loss of productivity.
• Managing security also costs.
• Need to perform risk analysis (which will be the
  next topic)

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Principles of Security

• Principle of easiest penetration
• an intruder will use any means of penetration
• Principles of timeliness
• items only need to be protected until they lose
  their value
• Principles of effectiveness
• controls must work, and they should be
  efficient, easy to use, and appropriate.

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Layers of technology (and Onion Model)

• In which layer should security mechanisms be
  placed ?
• Should controls be placed in more that one layer
  ?
• See slide 46 too.

Operating System
Kernel
Hardware
Services
Applications
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Layers

• The presence of layers is a feature of technology
• Separate layers often perform very different
  functions
• Similar functions are combined in one layer
• The boundary between two layers is usually easily
  defined
• Layers can often be independently implemented

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Vulnerabilities

• The three broad computing system resources are
• hardware
• interruption (denial of service), interception
  (theft)
• software
• interruption (deletion), interception,
  modification
• data
• interruption (loss), interception, modification
  and fabrication

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One method of defence

• By controls
• What should be the focus of the controls?
• For example should protection mechanisms focus
  on data or operations on that data or on the
  users who use the data?
• Since there are layers of technology, where
  controls should apply?
• Applications, services, operating systems,
  kernel, hardware.

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Controls

• Can be applied at hardware, software, physical
  or polices.
• Simple mechanisms or lots of features?
• Should defining and enforcing security mechanism
  be a centralised function?
• How to prevent access to the layer below the
  security mechanism?

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Examples of Controls

• Modern cryptology
• Encryption, authentication code, digital
  signature,etc.
• Software controls
• Standard development tools (design, code, test,
  maintain,etc)
• Operating systems controls
• Internal program controls (e.g access controls
  to data in a database)
• Firewalls

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Examples of Controls

• Hardware controls
• Security devices, smart cards,
• Physical controls
• Lock, guards, backup of data and software, thick
  walls, .
• Security polices and procedures
• User education
• Law

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Effectiveness of Controls

• Merely having controls does no good unless they
  are used properly. The factors that affect the
  effectiveness are
• Awareness of protection
• Likelihood of users
• Overlapping controls
• Periodic review

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Model for network security
Trusted Third party
Principal
Principal
Message
Gate Keeper
Message
Information channel
Secret Info.
Secret Info.
Opponent security threads and possible attacks
Borrowed from Stallings
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Two questions to ponder

• Having backup copies of the data is it a
  solution to security?
• The internetwork security model (the previous
  slide) has the gate keeper at the receiver (or
  destination) end why not at the sender (source)?