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ELEC5616 computer and network security


... the first world countries as part of Echelon, and other partner SIGINT networks. ... SIGINT on known military units e.g. email, voice transcripts ... – PowerPoint PPT presentation

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Title: ELEC5616 computer and network security

ELEC5616computer and network security
  • matt barrie
  • mattb_at_ee.usyd.edu.au

  • Understanding of security fundamentals
  • Introduction to applied cryptography
  • Issues with designing secure systems
  • Experience in designing and implementing one
  • Examination of real world case studies
  • Understanding of the cross-disciplinary issues
  • Why systems fail

about us
  • Matt is an External Lecturer
  • Chief Executive Officer of Ignition Networks.
  • Non Executive Director of Julius Finance, Inc.
  • Strategic Advisor to QuintessenceLabs (Quantum
  • Formerly
  • Chief Executive Officer of Sensory Networks, Inc.
  • Director of Packet Storm (packetstormsecurity.org)
    , which was at the time the worlds largest
    information security resource.
  • Ran the Systems and Network Assessment Practice
    at Kroll-OGara Information Security Group
  • Managing Director of Infilsec, a computer
    security consulting firm

  • Hash functions
  • Authentication
  • Secret key encryption
  • Public key encryption
  • Key exchange
  • Digital signatures
  • Cryptographic protocols
  • Secure programming
  • Real world systems and protocols
  • Political and legal issues
  • Attacks
  • How and why systems fail
  • The shape of things to come

  • Two lectures per week, for twelve weeks
  • Thursday 4pm 6pm (EE450)
  • One 2-hour lab working on a project
  • Friday 2 4pm (EE630)
  • Tutors
  • Greg Darke
  • Emma Fitzgerald
  • Assessment
  • Assignments Challenges (25)
  • Wargames (12.5)
  • Quiz on papers given out in class (2.5)
  • One Assignment (10)
  • Project (25)
  • Final Exam (50) two hours, closed book

  • All lectures are compulsory
  • All labs are compulsory
  • Attendance below 50 can be grounds for failure
  • It is your responsibility to make up missed

  • Cryptography and Network Security, William
    Stallings, (Prentice Hall), 4th Edition
  • Handbook of Applied CryptographyA. Menezes, P.
    van Oorschot, S. Vanstone (online)
  • URL http//www.cacr.math.uwaterloo.ca/hac/
  • 3. Lecture notes and additional reading material
    will also be handed out in class.
  • Highly recommended
  • Applied Cryptography, 2nd Ed., Bruce Schneier,
    (Wiley), 1996
  • Security Engineering, Ross Anderson, (Wiley), 2001

project part 1
  • It is 2009 and Big Brother is way ahead of
  • Naturally the Internet by now is fully tapped by
    the first world countries as part of Echelon, and
    other partner SIGINT networks.
  • Committed to the global war on terrorism, the
    worlds terrorist organisations plan to develop a
    global information exchange using civilian
    infrastructure (i.e. the Internet).
  • Naturally, none of the terrorists involved want
    to necessarily be identified as the buyers or
    sellers of this information (even to each other!)
    hence the need for an secure, anonymous
    platform for facilitating this exchange layered
    on the Internet
  • This exchange will be used by cells to trade
    classified information and dirty secrets through
    a wholesale information exchange.
  • SIGINT on known military units e.g. email, voice
  • Blueprints and eyeballs of bases and capitalist
    agent identities
  • Classified agency documents
  • Private video collections of dictators around the
  • The occasional bootleg Britney Spears MP3

  • Your group has been hired by a rogue cypherpunk
    cell to build a secure communications application
    for underground messaging, file transfers and
    secrets exchange
  • Think of it as a secure version of ICQ
    (www.icq.com) with the ability to buy and sell
    black market information
  • You may assume that anonymity will be handled by
    the underlying StealthNet network layers
  • Written in Java with crypto library support
  • Teams of two
  • You will be supplied with an insecure skeleton
    for reference

  • We will be providing challenges for you to
    solve as part of Wargames
  • There will be a leader board of highest scores
  • Challenges can be attempted individually or in
    teams (max. of 4)
  • IMPORTANT You do not need to solve all or even
    half the challenges!
  • Challenge difficulty will range from easy to
    extremely difficult-- by extremely difficult we
    mean that thousands of people have been trying
    for years to solve with no success, and these
    challenges may not even be solved in your
  • WARNING these challenges may be a tremendous
    drain on your time, and are mostly provided for
    your own interest and enjoyment
  • In the olden days some of the challenges had cash
    prizes (e.g. US30,000 prize for the RSA
    challenge). Unfortunately due to the Global
    Financial Crisis, this has been discontinued.
    However we will be substituting with some k-rad
    security prizes!
  • We will be giving out overall prizes for the top
    3 teams at the end of semester (final submission
    deadline Thursday _at_ midnight before the last

challenge marking
  • Each challenge is worth a different number of
    points based on the difficulty. Some challenges
    will also have a time limit.
  • There are two types of challenges that will be
  • Challenges with a single solution
  • Points will be determined by the number of people
    who have solved it
  • Your points will decay as more people submit
    correct answers
  • 2. Challenges with many or infinite numbers of
  • Goal is to find the best answer
  • Points will be determined by the quality of the
  • Better solutions get more points
  • You may submit multiple solutions as you find
    better answers
  • Points might still decay with multiple people
    solving the answer
  • Your mark for the challenges will be scaled
    versus all submissions at the end of the course
    and account for half your total assignment mark
    (or 12.5 of the total course mark)
  • REMEMBER you do have a life outside this course.
    Dont get carried away

  • Help algorithm
  • Check the website
  • http//www.ee.usyd.edu.au/mattb/2009/
  • If FAIL, post on the class message board
  • Linked from course website
  • others may already have asked your question and
    got an answer
  • others may be having the same problem
  • If FAIL, e-mail us
  • elec5616_at_ee.usyd.edu.au
  • we have a neural connection to the Internet

we are entering a brave new world ...
(No Transcript)
actual newspaper headlines
  • WebTV virus dials 911
  • GSM cell-phone encryption cracked by Birykof and
  • The number 7 blocks Belgian ATM machines
  • Ameriprises stolen laptop had data on 230,000
  • Tampered heart monitors, simulating failure to
    get human organs
  • Secret American spy photos broadcast unencrypted
    over satellite TV
  • Software flaw in submarine-launched ballistic
    missile system
  • Accidental launch of live Canadian Navy missile
    color-code mixup
  • Navy to use Windows 2000 on aircraft carriers
  • Classified data in wrong systems at Rocky Flats
    nuclear weapons plant
  • Russian nuclear warheads armed by computer
  • U.S. House approves life sentences for crackers
  • Courtesy of RISKS (http//catless.ncl.ac.uk/Risks/

and now, the bad news...
nothing is secure in the digital world
  • The digital world behaves differently to the
    physical world
  • Everything in the digital world is made of bits
  • Bits have no uniqueness
  • Its easy to copy bits perfectly
  • Therefore, if you have something, I can copy it
  • Information
  • Privileges
  • Identity
  • Media
  • Software
  • Digital money
  • Much of information security revolves around
    making it hard to copy bits

matts definition of information security
  • You spend X so that your opponent has to spend Y
    to do something you dont want them to do
  • Y is rarely greater than X
  • and there are lots of opponents
  • Its all a resource game
  • Time
  • Computational power (time x )
  • Implication
  • Given enough resources, someones going to get in
  • Given enough attackers, someones going to get in
  • Given enough time, someones going to get in
  • Thus all systems can and will fail
  • The trick is to raise the bar to an adequate
    level of (in)security for the resource you are
    trying to protect

security requirements
  • Everything you have been taught so far in
    engineering revolves around building dependable
    systems that work
  • Typically engineering efforts are associated with
    ensuring something does happen e.g. John can
    access this file
  • Security engineering traditionally revolves
    around building dependable systems that work in
    the face of a world full of clever, malicious
  • Typically security has been about ensuring
    something cant happen.e.g. the Chinese
    government cant access this file.
  • Reality is far more complex
  • Security requirements differ greatly between

why do systems fail?
  • Systems often fail because designers
  • Protect the wrong things
  • Protect the right things in the wrong way
  • Make poor assumptions about their systems
  • Do not understand their systems threat model
  • Fail to account for paradigm shifts (e.g. the
  • Fail to understand the scope of their system

bank security requirements
  • Core of a banks operations is its bookkeeping
  • Most likely threat internal staff stealing petty
  • Goal highest level of integrity
  • ATMs
  • Most likely threat petty thieves
  • Goal authentication of customers, resist attack
  • High value transaction systems
  • Most likely threat internal staff, sophisticated
  • Goal integrity of transactions
  • Internet banking
  • Most likely threat hacking the website or
  • Goal authentication and availability
  • Safe
  • Threat physical break-ins, stealing safe
  • Goal physical integrity, difficult to transport,
    slow to open

military communications
  • Electronic warfare systems
  • Objective jam enemy radar without being jammed
  • Goal covertness, availability
  • Result countermeasures, countercountermeasures
  • Military communications
  • Objective Low probability of intercept (LPI)
  • Goal confidentiality, covertness, availability
  • Result spread spectrum communications etc.
  • Compartmentalisation
  • Objective example logistics software-
    administration of boot polish different from
    stinger missiles
  • Goal confidentiality, availability, resilience
    to traffic analysis?
  • Nuclear weapons command control
  • Goal prevent weapons from being used outside the
    chain of command

hospital security requirements
  • Use of web based technologies
  • Goal harness economies of the Internet (EoI)
    e.g. online reference books
  • Goal integrity of data
  • Remote access for doctors
  • Goal authentication, confidentiality
  • Patient record systems
  • Goal nurses may only look at records of
    patients who have been in their ward in the last
    90 days
  • Goal anonymity of records for research
  • Paradigm shifts introduce new threats
  • Shift to online drug databases means paper
    records are no longer kept
  • Results in new threats on
  • availability e.g. denial of service of network
  • integrity e.g. malicious temporary tampering of

risk analysis
Risk Impact Matrix
Extreme High Medium Low
Certain 1 1 2 3 4 Likely 1 2 3 4 5 Moderate 2 3
4 5 6 Unlikely 3 4 5 6 7 Rare 4 5 6 7 7
1 severe must be managed by senior management
with a detailed plan 2 high detailed research
and management planning required at senior
levels 3 major senior management attention is
needed 4 significant management responsibility
must be specified 5 moderate manage by specific
monitoring or response procedures 6 low manage
by routine procedures 7 trivial unlikely to
need specific application of resources
axioms of information security
  • All systems are buggy
  • The bigger the system the more buggy it is
  • Nothing works in isolation
  • Humans are most often the weakest link
  • Its a lot easier to break a system than to make
    it secure

a system can be..
  • A product or component
  • e.g. software program, cryptographic protocol,
    smart card
  • plus infrastructure
  • e.g. PC, operating system, communications
  • plus applications
  • e.g. web server, payroll system
  • plus IT staff
  • plus users and management
  • plus customers and external users
  • plus partners, vendors
  • plus the law, the media, competitors,
    politicians, regulators

aspects of security
  • Authenticity
  • Proof of a messages origin
  • Integrity plus freshness (i.e. message is not a
  • Confidentiality
  • The ability to keep messages secret (for time t)
  • Integrity
  • Messages should not be able to be modified in
  • Attackers should not be able to substitute fakes
  • Non-repudiation
  • Cannot deny that a message was sent (related to
  • Availability

passive attacks
  • Those that do not involve modification or
    fabrication of data
  • Examples include eavesdropping on communications
  • Interception
  • An unauthorised party gains access to an asset
  • Release of message contents an attack on
  • Traffic analysis an attack on covertness

active attacks
  • Those which involve some modification of the data
    stream or creation of a false stream
  • Fabrication
  • An unauthorised party inserts counterfeit objects
    into the system
  • Examples include masquerading as an entity to
    gain access to the system
  • An attack on authenticity
  • Interruption
  • An asset of the system is destroyed or becomes
    unavailable or unusable
  • Examples include denial-of-service attacks on
  • An attack on availability
  • Modification
  • An unauthorised party not only gains access to
    but tampers with an asset
  • Examples include changing values in a data file
    or a virus
  • An attack on integrity

  • Secrecy
  • A technical term which refers to the effect of
    actions to limit access to information
  • Confidentiality
  • An obligation to protect someone or some
    organisations secrets
  • Privacy
  • The ability and/or right to protect the personal
    secrets of you or your family including
    invasions of your personal space
  • Privacy does not extend to corporations
  • Anonymity
  • The ability/desire to keep message
    source/destination confidentiality

  • A trusted system is one whose failure can break
    security policy.
  • A trustworthy system is one which wont fail.
  • A NSA employee caught selling US nuclear secrets
    to a foreign diplomat is trusted but not
  • In information security trust is your enemy.

trust is your enemy
  • You cannot trust software or vendors
  • They wont tell you their software is broken
  • They wont fix it if you tell them
  • You cannot trust the Internet nor its protocols
  • Its built from broken pieces
  • Its a monoculture something breaks ? everything
  • It was designed to work, not be secure
  • You cannot trust managers
  • They dont want to be laggards nor leaders
  • Security is a cost centre, not a profit centre!
  • You cannot trust the government
  • They only want to raise the resource game to
    their level
  • You cannot trust your employees or users
  • They are going to pick poor passwords
  • They are going to mess up the configuration and
    try to hack in

trust is your enemy
  • You cannot trust your peers
  • They are as bad as you
  • You cannot trust algorithms nor curves
  • Moores law does not keep yesterdays secrets
  • Tomorrow they might figure out how to factor
    large numbers
  • Tomorrow they might build a quantum computer
  • You cannot trust the security community
  • They are going to ridicule you when they find a
  • They are going to tell the whole world about it
  • You cannot trust information security
  • Its always going to be easier to break knees
    than break codes
  • You cannot trust yourself
  • You are human
  • One day you will screw up

tenet of information security
  • Security through obscurity does not work
  • Full disclosure of the mechanisms of security
    algorithms and systems (except secret key
    material) is the only policy that works
  • Kirchoffs Principle For a system to be truly
    secure, all secrecy must reside in the key
  • If the algorithms are known but cannot be broken,
    the system is a good system
  • If an algorithm is secret and no-one has looked
    at it, nothing can be said for its security

morals of the story
  • Nothing is perfectly secure
  • Information security is a resource game
  • Nothing works in isolation
  • Know your system
  • Know your threat model
  • Trust is your enemy
  • All systems can and will fail
  • Humans are usually the weakest link
  • Attackers often know more about your system than
    you do

  • Stallings
  • 1
  • Interesting Websites
  • http//www.csl.sri.com/users/neumann/illustrative.
  • http//www.packetstormsecurity.org
  • http//www.securityfocus.com
  • http//www.digicrime.com
  • http//www.cryptome.org
  • http//www.phrack.org
  • http//www.eff.org
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