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EE515/IS523 Think Like an Adversary Lecture 3 Introduction

EE515/IS523 Think Like an Adversary Lecture 3 Introduction. Yongdae Kim. Recap. http://security101.kr E-mail policy Include [ee515] or [is523] in the subject of your e-mail Student Survey http://bit.ly/SiK9M3. "the security mindset involves thinking about how things can be made to fail.

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EE515/IS523 Think Like an Adversary Lecture 3 Introduction

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  1. EE515/IS523 Think Like an AdversaryLecture 3Introduction Yongdae Kim

  2. Recap • http://security101.kr • E-mail policy • Include [ee515] or [is523] in the subject of your e-mail • Student Survey • http://bit.ly/SiK9M3

  3. "the security mindset involves thinking about how things can be made to fail. It involves thinking like an attacker, an adversary or a criminal. You don’t have to exploit the vulnerabilities you find, but if you don’t see the world that way, you’ll never notice most security problems.” - Bruce Schneier

  4. Who are the attackers? • No more script-kiddies • State-sponsored attackers • Attacker = a nation! • Hacktivists • Use of computers and computer networks as a means of protest to promote political ends • Hacker + Organized Criminal Group • Money! • Researchers

  5. State-Sponsored Attackers • 2012. 6: Google starts warning users who may be targets of government-sponsored hackers • 2010 ~: Stuxnet, Duqu, Flame, Gauss, … • Mikko (2011. 6): A Pandora’s Box We Will Regret Opening • 2010~: Cyber Espionage from China • Exxon, Shell, BP, Marathon Oil, ConocoPhillips, Baker Hughes • Canada/France Commerce Department, EU parliament • RSA Security Inc. SecurID • Lockheed Martin, Northrop Grumman, Mitsubushi

  6. Hacktivists • promoting expressive politics, free speech, human rights, and information ethics • Anonymous • To protest against SOPA, DDoS against MPAA, RIAA, FBI, DoJ, Universal music • Attack Church of Scientology • Support Occupy Wall Street • LulzSec • Hacking Sony Pictures (PSP jailbreaking) • Hacking Pornography web sites • DDoSing CIA web site (3 hour shutdown)

  7. Hacker + Organized Crime Group • No more script kiddies • Hackers seek to earn money through hacking • Traditional financial crime groups have difficulty with technology improvement • Hacker + Criminals! • HaaS = Hacking-as-a-Service

  8. Financial Cyber Crime Statistics • 14 adults become victims of cybercrime every second, totaling more than one million victims each day1 • Cybercriminals unleash 3.5 new threats targeting businesses every second2 1 (347M) (431M) 1 Norton Cybercrime Report 2011 2 Trend Micro “Small business is big business in cybercrime”

  9. Security Researchers • They tried to save the world by introducing new attacks on systems • Examples • Diebold AccuVote-TS Voting Machine • APCO Project 25 Two-Way Radio System • Kad Network • GSM network • Pacemakers and Implantable Cardiac Defibrillators • Automobiles, …

  10. Security Researchers • They tried to save the world by introducing new attacks on systems • Examples • Diebold AccuVote-TS Voting Machine • APCO Project 25 Two-Way Radio System • Kad Network • GSM network • Pacemakers and Implantable Cardiac Defibrillators • Automobiles, …

  11. Bug Bounty Program • Evans (Google): “Seeing a fairly sustained drop-off for the Chromium” • McGeehan (Facebook): The bounty program has actually outperformed the consultants they hire. • Google: Patching serious or critical bugs within 60 days • Google, Facebook, Microsoft, Mozilla, Samsung, …

  12. Nations as a Bug Buyer • ReVuln, Vupen, Netragard: Earning money by selling bugs • “All over the world, from South Africa to South Korea, business is booming in what hackers call zero days” • “No more free bugs.” • ‘In order to best protect my country, I need to find vulnerabilities in other countries’ • Examples • Critical MS Windows bug: $150,000 • Vupen charges $100,000/year for catalog and bug is sold separately • a zero-day in iOS system sold for $500,000 • Brokers get 15%.

  13. Basic Cryptography Yongdae Kim

  14. Eve Yves? The main players Bob Alice

  15. Attacks Normal Flow Destination Source Interruption: Availability Interception: Confidentiality Destination Destination Source Source Modification: Integrity Fabrication: Authenticity Destination Destination Source Source

  16. Taxonomy of Attacks • Passive attacks • Eavesdropping • Traffic analysis • Active attacks • Masquerade • Replay • Modification of message content • Denial of service

  17. Big picture Trusted third party (e.g. arbiter, distributor of secret information) Bob Alice Information Channel Message Message Secret Information Secret Information Eve

  18. Terminology for Encryption • A denotes a finite set called the alphabet • M denotes a set called the message space • M consists of strings of symbols from an alphabet • An element of M is called a plaintext • C denotes a set called the ciphertext space • C consists of strings of symbols from an alphabet • An element of C is called a ciphertext • K denotes a set called the key space • An element of K is called a key • Ee is an encryption function where e  K • Dd called a decryption function where d  K

  19. Encryption • Why do we use key? • Or why not use just a shared encryption function? Adversary Encryption Ee(m) = c Decryption Dd(c) = m c insecure channel m m Plaintext source destination Alice Bob

  20. SKE with Secure channel Adversary d Secure channel Key source e Encryption Ee(m) = c Decryption Dd(c) = m c Insecure channel m m Plaintext source destination Alice Bob

  21. PKE with insecure channel Passive Adversary e Insecure channel Key source d Encryption Ee(m) = c Decryption Dd(c) = m c Insecure channel m m Plaintext source destination Alice Bob

  22. e e’ Ee’(m) Public key should be authentic! • Need to authenticate public keys Ee(m) e Ee(m)

  23. Digital Signatures • Primitive in authentication and non-repudiation • Signature • Process of transforming the message and some secret information into a tag • Nomenclature • M is set of messages • S is set of signatures • SA: M ! S for A, kept private • VA is verification transformation from M to S for A, publicly known

  24. Key Establishment, Management • Key establishment • Process to whereby a shared secret key becomes available to two or more parties • Subdivided into key agreement and key transport. • Key management • The set of processes and mechanisms which support key establishment • The maintenance of ongoing keying relationships between parties

  25. Symmetric vs. Public key

  26. Symmetric key Encryption • Symmetric key encryption • if for each (e,d) it is easy computationally easy to compute e knowing d and d knowing e • Usually e = d • Block cipher • breaks up the plaintext messages to be transmitted into blocks of a fixed length, and encrypts one block at a time • Stream cipher • encrypt individual characters of plaintext message one at a time, using encryption transformation which varies with time

  27. Hash function and MAC • A hash function is a function h • compression • ease of computation • Properties • one-way: for a given y, find x’ such that h(x’) = y • collision resistance: find x and x’ such that h(x) = h(x’) • Examples: SHA-1, MD-5 • MAC (message authentication codes) • both authentication and integrity • MAC is a family of functions hk • ease of computation (if k is known !!) • compression, x is of arbitrary length, hk(x) has fixed length • computation resistance • Example: HMAC

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