Computer Security and Cryptography Partha Dasgupta, Arizona State University

2 The Problem If I didn't wake up, I'd still be sleeping.

3 Not just hype + paranoia u Internet hosts are under constant attack u Financial losses are mounting u Miscreants are getting smarter  (and so are consumers) u “National Security” risks were stated and then underplayed u Data loss threatens normal users, corporations, financial institutions, government and more u Questions: HOW? WHY? and What can we do?

4 Overview u Part 1: Security Basics u Part 2: Attacks u Part 3: Countermeasures u Part 4: Cryptography u Part 5: Network Security u Part 6: System Security u Part 7: State of the Art and Future

5 Part 1: Security Basics u Computer and Network Security basics u Hacking u Attacks and Risks u Countermeasures u Secrets and Authentication u Paranoia

6 Computer and Network Security u Keep computers safe from program execution that is not authorized u Keep data storage free from corruption u Keep data storage free from leaks u Keep data transmissions on the network private and un- tampered with u Ensure the authenticity of the transactions (or executions) u Ensure that the identification of the human, computer, resources are established  With a high degree of confidence  Do not get stolen, misused or misrepresented

7 Hacking or Cracking u Plain old crime u Phone Phreaking u Credit cards, the old fashioned way u Technology Hacks  Design deficiencies and other vulnerabilite  ATM, Coke Machines, Credit Cards, Social Engineering  Software hacks  Second channel attacks  RFID issues  Cell phone vulnerabilities  Grocery cards?

8 Attacks and Risks u “Attacks”  An attack is a method that compromises one or more of: - privacy (or confidentiality) - data integrity - execution integrity u Attacks can originate in many ways  System based attacks  Network based attacks  “Unintended Consequences” u Risk – a successful attack leads to “compromise”  Data can be stolen, changed or “spoofed”  Computer can be used for unauthorized purposes  Identity can be stolen  RISK can be financial

9 Attack Types u System based attacks  Virus, Trojan, rootkit  Adware, spyware, sniffers u A program has potentially infinite power  Can execute, spawn, update, communicate  Can mimic a human being  Can invade the operating system u Network based attacks  Eavesdropping  Packet modifications, packet replay  Denial of Service u Network attacks can lead to data loss and system attacks

10 Countermeasures u System Integrity Checks  Virus detectors  Intrusion detection systems  Software signatures u Network Integrity checks  Encryption  Signatures and digital certificates  Firewalls  Packet integrity, hashes and other cryptographic protocols u Bottom Line:  We have an arsenal for much of the network attacks  System security is still not well solved

11 What is at Risk? u Financial Infrastructure u Communication Infrastructure u Corporate Infrastructure u Confidentiality and Privacy at many levels u Economy u Personal Safety

12 The Shared Secret Fiasco u Our authentication systems (personal, financial, computing, communications) are all based on “shared secrets”  ID numbers, Account numbers, passwords, SS#, DOB u When secrets are shared, they are not secrets  They will leak! u Given the ability of computers to disseminate information, all shared secret schemes are at extreme risk  Media reports of stolen data is rampant The Fake ATM attack The check attack The extortion attack

13 How do secrets leak? u Malicious reasons u Simple mistakes u Oversight u Bad human trust management u Bad computer trust management u “Nothing can go wrong”  Please believe in Murphy!

14 Keeping Secrets? u Simple answer, not possible. u Encryption is good, but data has to be unencrypted somewhere u “Disappearing Ink”? u Use paper based documents, not scanned. u Public Key Encryption has much promise (PKI systems) u Shared secrets need to be eliminated as much as possible u Separate out of band communications  Phone, postal mail, person-to-person

15 Authentication u Shared secrets are used for authentication  Username/passwords u Multi-factor authentication  What you know  What you have  What you are, what you can do. u Most of the authentication methods are quite broken  Designed when networking was not around  PKI systems are better, but not deployed  Too many false solutions (dangerous, gives a feeling of security)

16 Passwords u The password is known to the host and the client  Under some password schemes the host does not know the password (e.g. Unix) u Passwords can leak from host or from client u Same password is used for multiple sites u Password managers are not too effective u “Good passwords” are not as good as you think u Invented for a completely different purpose, using passwords on the web, even with SSL encryption, is a bad idea

17 False Solutions u Biometrics  A digital bit string, or password that cannot be changed  Plenty of attacks possible, including framing u RFID identification  Plenty of attacks possible u Multi-Factor authentication  Better, but still not good u Smart cards (the not-so-smart ones)  Again, based on shared secrets, have attacks and limitations

18 Paranoia? u A large number of computers (consumer, business) are compromised or used for fraud  Viral infections, zombies  Many web servers are for fraudulent reasons u Spam is an indicator  Unprecedented lying, cheating u Adware, popups, spyware  All attempting to mislead, steer, and victimize u Identity theft, financial theft, cheating  Probably at an all time high u Security Awareness is often coupled with paranoia  It is necessary to be paranoid!

19 What is the point of an attack? u Get your shared secrets for financial gain u Espionage u Disruption Personal Corporate Financial System Identification

20 Computer Security u Software needs to be verifiably untampered and trusted u Networks need to be free from tampering/sniffing u Data has to be secure from stealing and tampering u End user protection u A coalescing of software, hardware and cryptography along with human intervention and multi-band communication.